Work-related infectious diseases among Korean workers compensated under the Industrial Accident Compensation Insurance Law, 2006–2011 Jun-Pyo Myong1,2, Yeon-Soon Ahn3, Hyoung-Ryoul Kim1,2, Youn Jeong Kim4, Chung Yill Park1,2, Jung-Wan Koo1,2 1
Department of Occupational and Environmental Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea, 2Department of Occupational and Environmental Medicine, and Center for Occupational and Environmental Medicine, Seoul St. Mary’s Hospital, The Catholic University of Korea, Seoul, Korea, 3 Department of Occupational and Environmental Medicine, Dongguk University, Ilsan Hospital, Goyang, Republic of Korea, 4Division of Infectious Disease, Department of Internal Medicine, Seoul St. Mary’s Hospital, The Catholic University of Korea, Seoul, Korea Background: Korea has no surveillance system for work-related infectious disease. However, these diseases are compensated by the Korea Workers’ Compensation & Welfare Service (KCOMWEL). Objectives: To understand the nature and distribution of compensated occupational infectious diseases in Korea. Methods: We used the KCOMWEL electronic database to analyze compensated cases of work-related occupational infectious disease. We reviewed and confirmed diagnoses excluding denied claims, secondary infections, dermatoid diseases, duplicated cases and those with missing information. We calculated the distribution of work-related infectious disease in Korea by occupation, calendar year, gender, age, and employment duration, as well as the annual compensated claim rates (per million). Results: We included 1,062 compensated cases of work-related infectious disease. The most common was scrub typhus (n5567, 53.4%), followed by tuberculosis (n5227, 21.4%), viral hepatitis (n555, 5.2%), and viral influenza (n553, 5.0%). A sudden increase in scrub typhus was observed in 2009. Unskilled laborers, including short-term contract workers in public sectors, were most commonly affected by these diseases, followed by health care professionals. Conclusions: Workers employed in forestry care in the public sectors and in hospitals were most vulnerable to infections. Proper surveillance systems to monitor infectious diseases among vulnerable working groups and improved prevention measures are needed. Keywords: Occupational diseases, Communicable diseases, Scrub typhus, Tuberculosis, Health care workers, Korea
Introduction According to a report from the Korea Centers for Disease Control and Prevention, infectious disease incidence has more than tripled over the last 10 years (from 39,105 cases in 2002 to 133,559 cases in 2010).1 The prevalence of tuberculosis, scrub typhus, and malaria have been steadily increasing. In 2009, a pandemic of swine flu (Influenza A/H1N1) also occurred in South Korea.1 Workers may face occupation-specific risks of infectious disease.2,3 Work-related infectious diseases
Correspondence to: Yeon-Soon Ahn, 814, Siksa-dong, Ilsandong-gu, Goyangsi, Gyeonggi-do 410-773, Republic of Korea. Email: ysahn@ dongguk.ac.kr
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were traditionally reported in health care workers (HCWs), laboratory workers, and workers in contact with animals.2,3 To protect workers, it is important for clinician and administrators to recognize new patterns of work-related infectious diseases. However, due to lack of surveillance measures in Korea, work-related infectious diseases may have been unrecognized. Furthermore, restricted access to information from the Korean government and/or the surveillance programs has made it difficult to monitor changes in work-related infectious diseases. To identify such changes in South Korea, we obtained and analyzed compensation data collected by the Korea Workers’ Compensation & Welfare Service (KCOMWEL) for 6 years between 2006 and 2011 in Korea.
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Materials and Methods In Korea, the Industrial Accident Compensation Insurance (IACI) operated by KCOMWEL covered a total of 14,198,748 employees in 2010, approximately 57.4% of the economically active population (24,748,000 persons).4 The IACI does not cover selfemployed workers and some atypical workers. In addition, approximately 1,502,382 government employees, teachers in private schools, and military officers (soldiers and other military staff) are covered by their own insurance system.4 The KCOMWEL determines the work-relatedness of infectious diseases through two systems. The first is a pre-approved list of work-related infectious diseases in HCWs including hepatitis A, B, & C, syphilis, acquired immune deficiency syndrome [AIDS], tuberculosis, rubella, measles, and influenza, and in non-HCWs as well as leptospirosis, scrub typhus, anthrax, brucellosis, epidemic hemorrhagic fever, malaria, and legionella [Pontiac fever]. The second is a determination by a committee of the work-relatedness of diseases not on the list of work-related infectious diseases. It is difficult to ascertain why the committee chooses to reject certain diseases. In February 2012, we asked the KCOMWEL for access to the electronic database of workers’ compensation claims under the IACI Law (data from 1 January 2006 to 31 December 2011). To protect subject’s personal information, the electronic database was cleared of all personal identification and workplace identifiers and provided to us in March, 2012. The electronic database consisted of approximately 30 variables, including the review process and decision results, information on the company, claimant, disease, and other work-related information. A total of 1,833 claimed infection disease cases were included in the KCOMWEL data provided to us. Claims which were denied (n5715) were excluded from this study. We also excluded (1) secondary infection due to injuries and other diseases (n520), (2) dermatoid diseases, such as eczema (n513), (3) duplicated cases (n514), and (4) missing information (n59). Finally, 1,062 cases remained in this study. For the purpose of our study, we focused on only a few variables, including the disease, the year of diagnosis, the claimant’s age, gender, job, employment duration, the type of industry, and infection routes. KCOMWEL classified cases according to the sixth version of the Korean Standard Classification of Diseases (KCD 6). Occupations were classified into nine categories according to the Korean Standard Classification of Occupations (KSCO). We calculated the distribution of work-related infectious diseases in Korea by occupation, calendar year, gender, age, and employment duration, as well as the annual compensated claim rates (per million).
Work-related infectious diseases among Korean Workers
The present study was approved by the Institutional Review Board of Seoul St. Mary’s Hospital, The Catholic University of Korea (approval ID: KC12EISI0737).
Results We included a total of 1,062 cases over the 6-year period (2006–2011). The number of work-related infectious disease peaked in 2009. Female workers accounted for 58.9% of all cases (n5625). The most prevalent age group was 60 years and over (n5321, 30.2%), followed by 50–59 years and 20–29 years. The proportion of workers with employment duration (from job start date to the date of disease diagnosis) of less than 1 year was 60.6%, with most cases among those employed between 3 and 6 months. When looking at occupation classification, the most common occupation was unskilled labors (n5590, 55.6%), followed by professionals and technicians (n5305, 28.7%)(Table 1). Table 2 shows the distribution of work-related infectious diseases by calendar year focusing on specific pathogens or modes of infections. The most common cause of work-related infectious disease was scrub typhus by Orientia tsutsugamushi (n5567, 53.4%), followed by tuberculosis (n5227, 21.4%), viral hepatitis (n555, 5.2%), and viral influenza (n553, 5.0%). In 2009, an epidemic of scrub typhus (20.5 persons per million) and hemorrhagic fever with renal syndrome by Hanta and Seoul viruses (1.8 persons per million) were observed. The total number of compensated cases of tuberculosis was 227 (21.4%) with pulmonary tuberculosis being the most common (n5189, 83.3%). The majority of viral hepatitis was caused by hepatitis C and hepatitis A. Viral influenza has been reported since 2009. There were 32 compensated cases of food poisoning caused by several bacteria and a single outbreak of workrelated dysentery by Shigella species was reported in 2007. For parasitic infection, scabies (n523, 2.2%) and malaria (n521, 2.0%) were the main causes of the disease. Brucellosis was intermittently reported. Table 3 shows the distribution of work-related infectious diseases by occupation for specific pathogens or the modes of infections. Professionals/ technicians and unskilled laborers had the highest number of compensated claims. A total of 511 unskilled laborers who contracted scrub typhus were compensated, 24 of whom suffered from hemorrhagic fever with renal syndrome over a period of 6 years. Short-term contract workers in the public sector, which was the most common occupation, accounted for 64.4% (n5365) of all scrub typhus cases. Professionals and technicians were compensated for tuberculosis (n5204), viral hepatitis (n543), influenza (n528), scrub typhus (n510), chicken pox (n56),
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scabies (n53), malaria (n520), and pneumonia (n52). In addition to occupation, the infection route was also analyzed. Vector-borne transmission (n5 619, 53%) was the most common infection route, followed by airborne (n5283, 26.6%), food-borne (n565, 6.1%), vehicle-borne (n564, 6.0%), and blood-borne transmissions (n531, 2.9%). The infection sources were animal reservoirs (n5673, 63.4%) and human reservoirs (patient and carrier; n5389, 46.7%). A focused review of HCWs among workers compensated for contracting work-related infectious diseases is presented in Table 4. The most common occupation was nurse (n5194, 66.2%), followed by medical laboratory technologist (n520, 6.8%), clinician (n518, 6.1%), nurse’s aide (n516, 5.5%), commercial caregiver (called ‘health care aides’, who are paid to help patients and disabled and elderly people) (n515, 5.1%), and other HCWs (n510, 4.8%). The most frequent work-related infectious disease was tuberculosis (n5207), followed by viral hepatitis (n543), influenza (n524), scabies (n511), chicken pox (n55), and others (n52).
and in Netherlands showed that the main cause of work-related infectious disease in both countries was diarrheal disease, followed by scabies in UK and tuberculosis in Netherlands.7–9 In Australia, based on the data from workers’ compensation claims, zoonoses, viral diseases excluding hepatitis, and parasitic diseases were the most common work-related infectious diseases.10 It seems likely that the reported frequencies and causes of work-related infectious diseases vary among different countries due to their specific reporting systems (surveillance vs workers’ compensation database) and exposure environments (economic status, industrial features, and culture). Therefore, for exact comparisons between countries, those factors should be considered. Tuberculosis is still one of the most important diseases in Korea.1 Although the Korean national database of the Korea Centers for Disease Control and Prevention (KCDC) did not provide us with the detailed routes of tuberculosis infection, we can extrapolate the details of the infection routes based on the KCOMWEL data. The majority of tuberculosis cases have been reported in HCWs.5,6,11 In our study, HCWs accounted for over 91% of tuberculosis cases and infection occurred while they came into contact with patients with tuberculosis. Therefore, infection control programs should be directed at preventing work-related tuberculosis among HCWs. Scrub typhus accounted for more than half of all work-related infectious disease cases. Interestingly, the number of compensated cases of scrub typhus in
Discussion Our study shows higher numbers of compensated infectious diseases in Korea compared to earlier years5,6; tuberculosis, hepatitis, and scrub typhus remained the most-compensated infections in all studies. However, results differed from those in other countries. A surveillance program in UK (THOR)
Table 1 Distribution of characteristics of work-related infectious diseases in Korea by calendar year, N (%) 2006 Gender Male Female Age (years) 20–29 30–39 40–49 50–59 60# missing Employment duration (months) duration,3 3#duration,6 6#duration,12 12#duration,24 24#duration,36 36#duration,48 duration§48 Occupation Administrator Professionals and technicians Clerks Service workers Sales workers Skilled agricultural Craft and related trades workers Plant, machine operators and assemblers Unskilled laborers
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2007
2008
2009
2010
2011
Total
45(42.1) 62(57.9)
78(41.5) 110(58.5)
46(36.5) 80(63.5)
162(42.7) 217(57.3)
66(41.8) 92(58.2)
40(38.5) 64(61.5)
437(41.1) 625(58.9)
40(37.4) 23(21.5) 13(12.1) 19(17.8) 11(10.3) 1(0.9)
48(25.5) 30(16.0) 35(18.6) 46(24.5) 29(15.4) 0(0.0)
38(30.2) 26(20.6) 11(8.7) 23(18.3) 27(21.4) 1(0.8)
35(9.2) 38(10.0) 44(11.6) 98(25.9) 164(43.2) 0(0.0)
33(20.9) 28(17.7) 18(11.4) 30(19.0) 49(31.0) 0(0.0)
17(16.3) 17(16.3) 17(16.3) 12(11.6) 41(39.5) 0(0.0)
211(19.9) 162(15.3) 138(13.0) 228(21.5) 321(30.1) 2(0.2)
17(15.9) 8(7.5) 8(7.5) 18(16.8) 15(14.0) 13(12.1) 28(26.2)
35(18.6) 14(7.4) 41(21.8) 21(11.2) 11(5.9) 19(10.1) 47(25.0)
18(14.3) 12(9.5) 30(23.8) 18(14.3) 10(7.9) 9(7.1) 29(23.1)
78(20.6) 183(48.3) 49(12.9) 19(5.0) 9(2.4) 8(2.1) 33(8.7)
29(18.3) 42(26.5) 21(13.3) 24(15.2) 8(5.1) 5(3.2) 29(18.4)
32(30.8) 12(11.5) 15(14.4) 9(8.7) 9(8.7) 4(3.8) 23(22.1)
209(19.7) 271(25.5) 164(15.4) 109(10.3) 62(5.8) 58(5.5) 189(17.8)
1(0.9) 50(46.8) 4(3.7) 6(5.6) 2(1.9) 0(0.0) 6(5.6) 2(1.9) 36(33.6)
5(2.7) 61(32.4) 22(11.8) 1(0.5) 0(0.0) 5(2.7) 14(7.4) 1(0.5) 79(42.0)
1(0.8) 56(44.4) 2(1.6) 1(0.8) 1(0.8) 6(4.8) 9(7.1) 1(0.8) 49(38.9)
7(1.8) 49(12.9) 5(1.3) 7(1.8) 2(0.5) 9(2.4) 11(2.9) 0(0.0) 289(76.4)
7(4.4) 52(32.9) 5(3.3) 4(2.5) 1(0.6) 1(0.6) 1(0.6) 1(0.6) 86(54.5)
2(1.9) 37(35.6) 4(3.8) 0(0.0) 0(0.0) 0(0.0) 6(5.8) 4(3.8) 51(49.1)
23(2.2) 305(28.6) 42(4.0) 19(1.8) 6(0.6) 21(2.0) 47(4.4) 9(0.8) 590(55.6)
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Hepatitis A Hepatitis B Hepatitis C Hepatitis E Influenza A/H1N1 Hemorrhagic Fever with Renal Syndrome Chicken pox Dengue fever Epidemic keratoconjunctivitis Bacterial Scrub typhus Mycobacterium tuberculosis{ Lung Bronchus Pleura Lymph node Meningitis Intestine or peritoneum Spine Breast Food poisoning, gastroenteritis Typhus Para-typhus Shigella species Other Brucellosis Streptococcus species Clostridium Vibrio vulnificus Leptospirosis Q fever Legionella Listeria Parasite Scabies Malaria Plasmodium vivax Plasmodium palcifarum Plasmodium Ovale & malariae Fungal Tinea
Viral Hepatitis
Causes
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0.0 0.4 0.2 0.2 0.0
0 5 2 3 0 0.1
2.9 3.3 2.9 0.2 0.2 0.2 0.0 0.0 0.0 0.0 0.2 0.0 0.0 0.0 0.2 0.4 0.0 0.1 0.0 0.0 0.0 0.0 0.0
36 42 36 2 2 3 0 0 0 0 3 0 0 0 2 5 0 1 0 0 0 0 0
1
0.4 0.2 0.1 0.1 0.0 0.0 0.5 0.1 0.1 0.0
Claim rate*
5 3 1 1 0 0 6 1 1 0
N
2006
5
7 6 5 0 1
74 58 47 1 5 9 1 2 0 0 17 0 0 15 2 0 4 0 2 0 0 0 1
8 0 2 6 0 0 5 0 0 0
N
Table 2 Work-related infectious diseases in Korea by calendar year
0.4
0.5 0.5 0.4 0.0 0.1
5.7 4.5 3.6 0.1 0.4 0.7 0.1 0.2 0.0 0.0 1.3 0.0 0.0 1.2 0.2 0.0 0.3 0.0 0.2 0.0 0.0 0.0 0.1
0.6 0.0 0.2 0.5 0.0 0.0 0.4 0.0 0.0 0.0
Claim rate*
2007
0
1 2 1 1 0
56 40 32 1 5 3 1 0 1 0 3 1 0 0 2 1 1 0 0 1 0 0 0
16 7 0 9 0 0 2 3 0 0
N
0.0
0.1 0.2 0.1 0.1 0.0
4.2 3.0 2.4 0.1 0.4 0.2 0.1 0.0 0.1 0.0 0.2 0.1 0.0 0.0 0.2 0.1 0.1 0.0 0.0 0.1 0.0 0.0 0.0
1.2 0.5 0.0 0.7 0.0 0.0 0.2 0.2 0.0 0.0
Claim rate*
2008
1
9 4 3 0 1
276 29 24 1 1 2 1 0 1 0 4 1 2 0 1 1 1 1 0 0 1 1 0
9 8 0 1 0 26 13 2 1 0
N
0.1
0.7 0.3 0.2 0.0 0.1
20.5 2.2 1.8 0.1 0.1 0.1 0.1 0.0 0.1 0.0 0.3 0.1 0.1 0.0 0.1 0.1 0.1 0.1 0.0 0.0 0.1 0.1 0.0
0.7 0.6 0.0 0.1 0.0 1.8 0.0 0.1 0.1 0.0
Claim rate*
2009
1
1 3 2 1 0
76 31 28 0 1 3 0 0 0 1 1 0 0 0 1 1 1 1 0 0 0 0 0
10 2 0 7 1 26 5 1 0 0
N
0.1
0.1 0.2 0.1 0.1 0.0
5.4 2.2 0.2 0.0 0.1 0.2 0.0 0.0 0.0 0.1 0.1 0.0 0.0 0.0 0.1 0.1 0.1 0.1 0.0 0.0 0.0 0.0 0.0
0.7 0.1 0.0 0.5 0.1 1.8 0.4 0.1 0.0 0.0
Claim rate*
2010
0
5 1 0 0 1
49 27 22 1 3 0 0 1 0 0 4 1 3 0 0 0 0 1 0 0 0 0 0
7 3 0 4 0 1 3 0 3 1
N
0.0
0.3 0.1 0.0 0.0 0.1
3.3 1.8 1.5 0.1 0.2 0.0 0.0 0.1 0.0 0.0 0.3 0.1 0.2 0.0 0.0 0.0 0.0 0.1 0.0 0.0 0.0 0.0 0.0
0.5 0.2 0.0 0.3 0.0 0.1 0.2 0.0 0.2 0.1
Claim rate*
2011
8(0.8)
23(2.1) 21(2.0) 13(1.2) 5(0.5) 3(0.3)
567(53.4) 227(21.4) 189 6 17 20 3 3 2 1 32(3.0) 3(0.3) 5(0.5) 15(1.4) 8(0.8) 8(0.8) 7(0.6) 4(0.4) 2(0.2) 1(0.1) 1(0.1) 1(0.1) 1(0.1)
55(5.2) 23(2.1) 3(0.3) 28(2.6) 1(0.1) 53(5.0) 34(3.2) 7(0.6) 5(0.5) 1(0.1)
Total n(%)
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0.0 0.0 0.1 7.1 *: Annual compensated work-related infectious disease claim rate per million {: duplication of sites was allowed. The number of denominator (thousand persons) at each year: (2006) 12,546; (2007) 12,995; (2008) 13,245; (2009) 13,459; (2010) 14,198; (2011) 14 700.
0 0 2 104 0.0 0.0 0.0 11.1 0 0 0 158 0.0 0.0 0.0 28.2 0 0 0 379 0.0 0.0 0.0 9.5 0 0 0 126 0.0 0.1 0.0 14.5 0 1 0 188 1 0 0 107 Others Cellulitis Subcutaneous abscess Pneumonia Total
0.1 0.0 0.0 8.5
Claim rate* N Causes
Claim rate*
N
Claim rate*
N
Claim rate*
N
Claim rate*
N
Claim rate*
N
2011 2010 2009 2008 2007 2006 Table 2 Continued 348
1(0.1) 1(0.1) 2(0.2) 1,062(100.0)
Work-related infectious diseases among Korean Workers
Total n(%)
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2009 was much higher than in other years (n5365, 64.4%). To understand the reason for this epidemic, it was important to identify the occupation that accounted for this spike in scrub typhus incidence. To overcome the effects of the global recession, which began in late 2008, the Korean government hired approximately 250,000 and 100,000 short-term contract workers in 2009 and 2010, respectively.12–14 Workers aged 60 years or over accounted for 47.9% and 57.2% of participants in 2009 and 2010, respectively.12 In the present study, the mean age of scrub typhus cases was 60.2 years and the most common tasks for these workers were outdoor activities for forestry and park care for local governments. Thus, public programs for creating jobs may have accounted for an epidemic of workrelated scrub typhus. Government administrators should consider these results as important side-effects of their policies and clinicians should also closely observe the patterns of epidemics in work-related infectious diseases and prevent them from epidemics through education initiatives. Work-related viral hepatitis, such as hepatitis B and C, was common among HCWs.5,6,15 It is well known that nurses and interns are most vulnerable to needle stick injury (NSI); incidence of NSI (incidence/ 100 persons/year) in Korea was 5.22 for nurses and 29.52 for interns,16 which is consistent with the results of previous reports and our finding that addition to nurses, interns were more susceptible to work-related viral hepatitis from NSI than any other clinicians (residents and faculty) and other HCWs. Thus, further management for prevention and evaluation is needed for the most vulnerable HCWs, particularly interns and nurses. The number of hepatitis B cases was smaller than that of hepatitis C cases, likely because hepatitis B has been regulated by the national vaccine schedule since 1995, whereas hepatitis C has not.17,18 It seems that workers who experienced NSI according to hepatitis B, i.e. young generation who had undergone hepatitis B immunization might not claim for HBV.1 However, those who experienced NSI resulting in hepatitis C were required to undergo the post-NSI care program covered by the IACI. This may be responsible for small number of hepatitis B being reported in IACI compared to hepatitis C. In this study, hepatitis A was compensated more frequently than hepatitis B (Table 2). Comparing our data to a previous study,5 the number of workers compensated for contracting work-related hepatitis A increased from 1 in 2001–2003 to 23 in 2006–2011. One of reason for this is an increase of hepatitis A infection in the general population (reported cases by surveillance system; 105 in 2001 and 13,559 in 2009).1 Anti-hepatitis A (HAV) seroprevalence may play an important role in
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Table 3 Work-related infectious disease in Korea from 2006 through 2011 by standard occupation Standard occupation Causes Viral Hepatitis Hepatitis Hepatitis Hepatitis Hepatitis
A B C E
Influenza A/H1N1 Hemorrhagic fever with renal syndrome Chicken pox Dengue fever Epidemic keratoconjunctivitis Bacterial Scrub typhus Mycobacterium tuberculosis Food poisoning, gastroenteritis Typhus Para-typhus Shigella species Other Brucellosis Streptococcus species Clistrideum Vibrio vulnificus Leptospirosis Q fever Legionella Listeria Parasite Scabies Malaria Fungal Tinea Others Cellulitis Subcutaneous abscess Pneumonia Total
A
B
C
D
E
F
G
H
I
Total n(%)
0 0 0 0 0 9 2 0 0 0
43 12 2 28 1 28 1 6 1 1
2 1 1 0 0 9 1 0 0 0
0 0 0 0 0 0 0 0 0 0
1 1 0 0 0 1 1 0 1 0
0 0 0 0 0 0 1 0 0 0
5 5 0 0 0 1 2 1 0 0
0 0 0 0 0 0 2 0 3 0
4 4 0 0 0 5 24 0 0 0
55(5.2) 23(2.1) 3(0.3) 28(2.6) 1(0.1) 53(5.0) 34(3.2) 7(0.6) 5(0.5) 1(0.1)
0 1 3 0 2 0 1 0 1 0 1 0 0 0 1
10 204 3 1 0 0 2 0 2 0 0 0 0 0 0
3 3 19 2 1 15 1 0 0 0 0 0 0 0 0
0 6 0 0 0 0 0 6 0 0 0 0 0 0 0
0 0 2 0 1 0 1 0 0 0 0 0 0 0 0
20 0 0 0 0 0 0 0 0 0 0 0 0 0 0
21 4 1 0 1 0 0 1 1 2 0 1 0 0 0
2 0 2 0 0 0 2 0 0 0 0 0 0 0 0
511 9 2 0 0 0 2 1 3 2 1 0 1 1 0
567(53.4) 227(21.4) 32(3.0) 3(0.3) 5(0.5) 15(1.4) 9(0.8) 8(0.8) 7(0.6) 4(0.4) 2(0.2) 1(0.1) 1(0.1) 1(0.1) 1(0.1)
0 4
3 2
0 2
6 1
0 0
0 0
0 7
0 0
14 5
23(2.1) 21(2.0)
1
0
1
0
0
0
0
0
6
8(0.8)
0 0 0 23
0 0 2 306
0 1 0 41
0 0 0 19
0 0 0 6
0 0 0 21
0 0 0 47
0 0 0 9
1 0 0 590
1(0.1) 1(0.1) 2(0.2) 1,062(100.0)
A: Administrator; B: Professionals and technicians; C: Clerks; D: Service workers; E: Sales workers; F: Skilled agricultural; G: Craft and related trades workers; H: Plant and machine operators and assemblers; I: Unskilled laborers.
explaining this change. Based on a Korean longitudinal study on HAV seroprevalences in children and adolescents over two decades, the rates decreased (a
similar decrease was not found in the older generation).19,20 These results are consistent with ours showing that an age of workers compensated for hepatitis A
Table 4 Distribution of infectious diseases among health care workers by job Viral hepatitis Tuberculosis Job title Nurse Medical laboratory technologist Clinician Nurse’s aide Commercial caregiver Dental technician Radiology technician Others Total
A
B
C
Total
Influenza
Scabies
Chicken pox
Others
Total
n(%)
n
n
n
n(%)
n(%)
n(%)
n(%)
n(%)
n(%)
150(72.5) 14(6.8)
5 1
2 0
25 0
32(74.4) 1(2.2)
8(33.3) 5(20.8)
0(0.0) 0(0.0)
1(20.0) 0(0.0)
3*(100.0) 0(0.0)
194(66.2) 20(6.9)
12(5.8) 11(5.3) 2(1.0) 2(1.0) 6(2.8) 10(4.8){ 207(100.0)
1 2 2 2 0 0 13
0 0 0 0 0 0 2
2 1 0 0 0 0 28
1(4.2) 3(7.0){ 3(7.0) 0(0.0) 2(4.7) 0(0.0) 2(4.7) 4(16.7) 0(0.0) 1(4.2) 0(0.0) 5(20.8)1 43(100.0) 24(100.0)
0(0.0) 0(0.0) 11(100.0) 0(0.0) 0(0.0) 0 11(100.0)
2(40.0) 2(40.0) 0(0.0) 0(0.0) 0(0.0) 0(0.0) 5(100.0)
0(0.0) 0(0.0) 0(0.0) 0(0.0) 0(0.0) 0(0.0) 3(100.0)
18(6.1) 16(5.5) 15(5.1) 8(2.7) 7(2.4) 15(5.1) 293(100.0)
*: 2 of pneumonia, 1 of epidemic keratoconjunctivitis. { Interns (n53). { Physical therapist (n52); electromyogram technician (n51); electrocardiogram technician (n51); emergency aid worker (n51); sterilization room worker (n51); hospital coordinator (n51); security officer (n51); office worker (n51); laundry worker (n51). 1 Unskilled laborer (n52); cleaner (n51); office worker (n51); social worker (n51).
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(n523) was 29.8 years (SD¡4.1) (data not shown). Therefore, hepatitis A vaccination should be encouraged in young workers. Business travel-related infections emerged between 2006 and 2011. In addition to Korea when an endemic of malaria caused by Plasmodium vivax occurred, workers receiving compensation for malaria caused by P. falcifarum and P. ovale might be due to international business travel-related infection.1 Workers compensated for hepatitis E, dengue fever, and Q fever were also related to international business travel in KCOMWEL investigation data. Clinicians should provide business travelers with proper precautions and vaccinations and administrators should educate and inform workers planning international business travels on the available prevention methods. As explained previously, the IACI covered 57.4% of the economically active population in 2010. This is one of the main limitations of this study. The IACI did not cover professional soldiers, so we might have underestimated the actual numbers of work-related occupational diseases, such as scrub typhus, tuberculosis, and hemorrhagic fever with renal syndrome by Hanta or Seoul virus.4 A total of 651 cases of brucellosis were reported by the KCDC between 2001 and 2010.21 In a review of farmers’ diseases, the cases of reported brucellosis increased from 0 in 2001 to 101 in 2007.22 Work-related brucellosis may be underestimated in our study. This is because selfemployed workers (including farmers) were not covered by the IACI. All of the compensated brucellosis cases in this study were contract workers; therefore, these results should be carefully interpreted. In addition, IACI only covered cases with 3 days and more of recuperation. This may also have led to under-reporting (cases of work-related infectious diseases, such as travelers’ diarrhea treated with simple hydration or 1-day rest and tinea infection). In spite of these limitations, our study has some strengths. It accessed data from the electronic database of cases submitted to the KCOMWEL. Also, work-relatedness was evaluated by KCOMWEL’s physician or a panel of clinicians, including occupational physicians and other specialists. In some cases, work-relatedness was evaluated after an epidemiologic investigation by the Occupational Safety and Health Research Institute (OSHRI) was carried out. Therefore, this data could provide accurate information on the relationship between occupation/task and the onset of infection. We can also understand the longitudinal distribution of work-related infectious diseases in Korea. This study provided administrators with valuable information on prevention strategies for workrelated infectious diseases in several vulnerable working groups, such as HCWs and short-term contractors in public sector. In conclusion, all information obtained in
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this study will be useful for clinicians to explain reasons for several work-related infectious disease endemics and to establish good strategies to prevent them.
Conflict of Interest The authors state that they have no competing financial interests to declare.
Acknowledgements No acknowledgements
References 1 Korea Centers for Disease Control & Prevention. Yearbook of national disease control. Seoul: Korea Centers for Disease Control & Prevention; 2011 (in Korean). 2 Panilio AL, Gerberding JL. Occupational infectious diseases. In: Rosenstock L, Cullen MR, Brodkin CA, Redlich CA, editors. Textbook of clinical occupational and environmental medicine, 2nd edn. Philadelphia: Elsevier Saunders; 2005. p. 469–51. 3 Kieckhaus KD. Occupational infections. In: Rom WN, Markowitz SB, editors. Environmental and occupational medicine, 4th edn. Philadelphia: Lippincott Williams &Wilkins, a Walters Kluwer business; 2007. p. 708–30. 4 Workers’ Compensation Research Center. Industrial accident compensation insurance & employment insurance collection data & analysis (Year 2010). Seoul: Workers’ Compensation Research Center; 2011 (in Korean). 5 Ahn YS, Kang SK, Kim KJ. Analysis of occupational diseases compensated with the industrial accident compensation insurance from 2001 to 2003. Korean J Occup Envrion Med. 2004;16:139–54 (in Korean). 6 Ahn YS, Kang SK, Kwon HG, Chung HK. Analysis of occupational disease by approved Korea Laor Welfare Corporation in 1999. Korean J Occup Envrion Med. 2001;13:449–60 (in Korean). 7 Health and Safety Executive. New cases of assessed disablement by disease (excluding lung diseases) 1990 to latest year [document on the Internet]; 2012 [cited 2013 Jan 10]. Available from: http:// www.hse.gov.uk/statistics/tables/index.htm#iidb. 8 National Institute for Public Health and the Environment. Surveillance of work-related infectious diseases in the Netherlands in 2009 [document on the Internet]. Bilthoven: National Institute for Public Health and the Environment; 2010 [cited 2013 Jan 10]. Available from: http://www.rivm.nl/ bibliotheek/rapporten/205014008.pdf. 9 Statistics Netherlands. Statistical yearook 2010 [document on the Internet]. Hague: Sdu publishers; 2010 [cited 2013 Jan 10]. Available from: http://www.cbs.nl/NR/rdonlyres/CBFF2453C370-4E7A-9271-0020DC62DC4E/0/2010a3pub.pdf. 10 Australian Safety and Compensation Council. Work-related infectious and parasitic diseases Australia [document on the Internet]; 2006 [cited 2013 Jan 10]. Available from: http://www. safeworkaustralia.gov.au/sites/SWA/AboutSafeWorkAustralia/ WhatWeDo/Publications/Documents/415/Workrelated_Infectious_ parastitic_disease_Australia.pdf. 11 Ahn YS, Lim HS. Occupational infectious diseases among Korean health care workers compensated with Industrial Accident Compensation Insurance from 1998 to 2004. Ind Health. 2008;46:448–54. 12 Park CI. The short-term contracted working in Public sectors and creating job. In: The Korea institute for Health and Social Affairs (KIHASA), editor. 2009 Policy agenda for social expenditure. Seoul: Dae-Myoung Planning; 2010. p 99–130 (in Korean). 13 People’s Solidarity for Participatory Democracy (PSPD). Issue report: reports on the short-term contract working in Public sectors in 2010 [document on the Internet]. Seoul: People’s Solidarity for Participatory Democracy (PSPD); 2010 [cited 2013 Jan 10]. Available from: http://www.peoplepower21.org/ Labor/613137 (in Korean). 14 The Ministry of Public Administration and Security. Creating job project [website on the Internet]. Seoul: The Ministry of Public Administration and Security; 2011 [cited 2013 Jan 10]. Available from: http://www.mopas.go.kr/gpms/hope.html (in Korean).
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15 Averhoff FM, Glass N, Holtzman D. Global burden of hepatitis C: considerations for healthcare providers in the United States. Clin Infect Dis. 2012;55 Suppl 1:S10–5. 16 Occupational Safety & Health Research Institute. Development and administration of needlestick injury surveillance system for healthcare personnel. Incheon: Occupational Safety & Health Research Institute; 2011 (in Korean). 17 Chae HB, Kim JH, Kim JK, Yim HJ. Current status of liver diseases in Korea: hepatitis B. Korean J Hepatol. 2009;15(Suppl 6):S13–24. 18 Choung JM, Kim JC, Eun SH, Hwang PH, Nyhambat B, Kilgore P, et al. Study on vaccination state in children: Jeonbuk province, 2000. J Korean Pediatr Soc. 2002;45:1234–40 (in Korean).
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19 Sohn YM, Rho HO, Park MS, Park JH, Choi BY, Ki M, et al. The changing epidemiology of hepatitis A in children and the consideration of active immunization in Korea. Yonsei Med J. 2000;41:34–9. 20 Lee D, Ki M, Lee A, Lee KR, Park HB, Kim CS, et al. A nationwide seroprevalence of total antibody to hepatitis A virus from 2005 to 2009: age and area-adjusted prevalence rates. Korean J Hepatol. 2011;17:44–50 (in Korean). 21 Jang Y, Kim H, Bang HA, Lee MJ, Che NH, Lee WC. Epidemiological aspects of human brucellosis and leptospirosis outbreaks in Korea. J Clin Med Res. 2012;3:199–202. 22 Lee K, Lim HS. Work-related injuries and diseases of farmers in Korea. Ind Health. 2008;46:424–34.
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Department of Occupational and Environmental Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea, 2Department of Occupational and Environmental Medicine, and Center for Occupational and Environmental Medicine, Seoul St. Mary’s Hospital, The Catholic University of Korea, Seoul, Korea, 3 Department of Occupational and Environmental Medicine, Dongguk University, Ilsan Hospital, Goyang, Republic of Korea, 4Division of Infectious Disease, Department of Internal Medicine, Seoul St. Mary’s Hospital, The Catholic University of Korea, Seoul, Korea Background: Korea has no surveillance system for work-related infectious disease. However, these diseases are compensated by the Korea Workers’ Compensation & Welfare Service (KCOMWEL). Objectives: To understand the nature and distribution of compensated occupational infectious diseases in Korea. Methods: We used the KCOMWEL electronic database to analyze compensated cases of work-related occupational infectious disease. We reviewed and confirmed diagnoses excluding denied claims, secondary infections, dermatoid diseases, duplicated cases and those with missing information. We calculated the distribution of work-related infectious disease in Korea by occupation, calendar year, gender, age, and employment duration, as well as the annual compensated claim rates (per million). Results: We included 1,062 compensated cases of work-related infectious disease. The most common was scrub typhus (n5567, 53.4%), followed by tuberculosis (n5227, 21.4%), viral hepatitis (n555, 5.2%), and viral influenza (n553, 5.0%). A sudden increase in scrub typhus was observed in 2009. Unskilled laborers, including short-term contract workers in public sectors, were most commonly affected by these diseases, followed by health care professionals. Conclusions: Workers employed in forestry care in the public sectors and in hospitals were most vulnerable to infections. Proper surveillance systems to monitor infectious diseases among vulnerable working groups and improved prevention measures are needed. Keywords: Occupational diseases, Communicable diseases, Scrub typhus, Tuberculosis, Health care workers, Korea
Introduction According to a report from the Korea Centers for Disease Control and Prevention, infectious disease incidence has more than tripled over the last 10 years (from 39,105 cases in 2002 to 133,559 cases in 2010).1 The prevalence of tuberculosis, scrub typhus, and malaria have been steadily increasing. In 2009, a pandemic of swine flu (Influenza A/H1N1) also occurred in South Korea.1 Workers may face occupation-specific risks of infectious disease.2,3 Work-related infectious diseases
Correspondence to: Yeon-Soon Ahn, 814, Siksa-dong, Ilsandong-gu, Goyangsi, Gyeonggi-do 410-773, Republic of Korea. Email: ysahn@ dongguk.ac.kr
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were traditionally reported in health care workers (HCWs), laboratory workers, and workers in contact with animals.2,3 To protect workers, it is important for clinician and administrators to recognize new patterns of work-related infectious diseases. However, due to lack of surveillance measures in Korea, work-related infectious diseases may have been unrecognized. Furthermore, restricted access to information from the Korean government and/or the surveillance programs has made it difficult to monitor changes in work-related infectious diseases. To identify such changes in South Korea, we obtained and analyzed compensation data collected by the Korea Workers’ Compensation & Welfare Service (KCOMWEL) for 6 years between 2006 and 2011 in Korea.
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Materials and Methods In Korea, the Industrial Accident Compensation Insurance (IACI) operated by KCOMWEL covered a total of 14,198,748 employees in 2010, approximately 57.4% of the economically active population (24,748,000 persons).4 The IACI does not cover selfemployed workers and some atypical workers. In addition, approximately 1,502,382 government employees, teachers in private schools, and military officers (soldiers and other military staff) are covered by their own insurance system.4 The KCOMWEL determines the work-relatedness of infectious diseases through two systems. The first is a pre-approved list of work-related infectious diseases in HCWs including hepatitis A, B, & C, syphilis, acquired immune deficiency syndrome [AIDS], tuberculosis, rubella, measles, and influenza, and in non-HCWs as well as leptospirosis, scrub typhus, anthrax, brucellosis, epidemic hemorrhagic fever, malaria, and legionella [Pontiac fever]. The second is a determination by a committee of the work-relatedness of diseases not on the list of work-related infectious diseases. It is difficult to ascertain why the committee chooses to reject certain diseases. In February 2012, we asked the KCOMWEL for access to the electronic database of workers’ compensation claims under the IACI Law (data from 1 January 2006 to 31 December 2011). To protect subject’s personal information, the electronic database was cleared of all personal identification and workplace identifiers and provided to us in March, 2012. The electronic database consisted of approximately 30 variables, including the review process and decision results, information on the company, claimant, disease, and other work-related information. A total of 1,833 claimed infection disease cases were included in the KCOMWEL data provided to us. Claims which were denied (n5715) were excluded from this study. We also excluded (1) secondary infection due to injuries and other diseases (n520), (2) dermatoid diseases, such as eczema (n513), (3) duplicated cases (n514), and (4) missing information (n59). Finally, 1,062 cases remained in this study. For the purpose of our study, we focused on only a few variables, including the disease, the year of diagnosis, the claimant’s age, gender, job, employment duration, the type of industry, and infection routes. KCOMWEL classified cases according to the sixth version of the Korean Standard Classification of Diseases (KCD 6). Occupations were classified into nine categories according to the Korean Standard Classification of Occupations (KSCO). We calculated the distribution of work-related infectious diseases in Korea by occupation, calendar year, gender, age, and employment duration, as well as the annual compensated claim rates (per million).
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The present study was approved by the Institutional Review Board of Seoul St. Mary’s Hospital, The Catholic University of Korea (approval ID: KC12EISI0737).
Results We included a total of 1,062 cases over the 6-year period (2006–2011). The number of work-related infectious disease peaked in 2009. Female workers accounted for 58.9% of all cases (n5625). The most prevalent age group was 60 years and over (n5321, 30.2%), followed by 50–59 years and 20–29 years. The proportion of workers with employment duration (from job start date to the date of disease diagnosis) of less than 1 year was 60.6%, with most cases among those employed between 3 and 6 months. When looking at occupation classification, the most common occupation was unskilled labors (n5590, 55.6%), followed by professionals and technicians (n5305, 28.7%)(Table 1). Table 2 shows the distribution of work-related infectious diseases by calendar year focusing on specific pathogens or modes of infections. The most common cause of work-related infectious disease was scrub typhus by Orientia tsutsugamushi (n5567, 53.4%), followed by tuberculosis (n5227, 21.4%), viral hepatitis (n555, 5.2%), and viral influenza (n553, 5.0%). In 2009, an epidemic of scrub typhus (20.5 persons per million) and hemorrhagic fever with renal syndrome by Hanta and Seoul viruses (1.8 persons per million) were observed. The total number of compensated cases of tuberculosis was 227 (21.4%) with pulmonary tuberculosis being the most common (n5189, 83.3%). The majority of viral hepatitis was caused by hepatitis C and hepatitis A. Viral influenza has been reported since 2009. There were 32 compensated cases of food poisoning caused by several bacteria and a single outbreak of workrelated dysentery by Shigella species was reported in 2007. For parasitic infection, scabies (n523, 2.2%) and malaria (n521, 2.0%) were the main causes of the disease. Brucellosis was intermittently reported. Table 3 shows the distribution of work-related infectious diseases by occupation for specific pathogens or the modes of infections. Professionals/ technicians and unskilled laborers had the highest number of compensated claims. A total of 511 unskilled laborers who contracted scrub typhus were compensated, 24 of whom suffered from hemorrhagic fever with renal syndrome over a period of 6 years. Short-term contract workers in the public sector, which was the most common occupation, accounted for 64.4% (n5365) of all scrub typhus cases. Professionals and technicians were compensated for tuberculosis (n5204), viral hepatitis (n543), influenza (n528), scrub typhus (n510), chicken pox (n56),
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scabies (n53), malaria (n520), and pneumonia (n52). In addition to occupation, the infection route was also analyzed. Vector-borne transmission (n5 619, 53%) was the most common infection route, followed by airborne (n5283, 26.6%), food-borne (n565, 6.1%), vehicle-borne (n564, 6.0%), and blood-borne transmissions (n531, 2.9%). The infection sources were animal reservoirs (n5673, 63.4%) and human reservoirs (patient and carrier; n5389, 46.7%). A focused review of HCWs among workers compensated for contracting work-related infectious diseases is presented in Table 4. The most common occupation was nurse (n5194, 66.2%), followed by medical laboratory technologist (n520, 6.8%), clinician (n518, 6.1%), nurse’s aide (n516, 5.5%), commercial caregiver (called ‘health care aides’, who are paid to help patients and disabled and elderly people) (n515, 5.1%), and other HCWs (n510, 4.8%). The most frequent work-related infectious disease was tuberculosis (n5207), followed by viral hepatitis (n543), influenza (n524), scabies (n511), chicken pox (n55), and others (n52).
and in Netherlands showed that the main cause of work-related infectious disease in both countries was diarrheal disease, followed by scabies in UK and tuberculosis in Netherlands.7–9 In Australia, based on the data from workers’ compensation claims, zoonoses, viral diseases excluding hepatitis, and parasitic diseases were the most common work-related infectious diseases.10 It seems likely that the reported frequencies and causes of work-related infectious diseases vary among different countries due to their specific reporting systems (surveillance vs workers’ compensation database) and exposure environments (economic status, industrial features, and culture). Therefore, for exact comparisons between countries, those factors should be considered. Tuberculosis is still one of the most important diseases in Korea.1 Although the Korean national database of the Korea Centers for Disease Control and Prevention (KCDC) did not provide us with the detailed routes of tuberculosis infection, we can extrapolate the details of the infection routes based on the KCOMWEL data. The majority of tuberculosis cases have been reported in HCWs.5,6,11 In our study, HCWs accounted for over 91% of tuberculosis cases and infection occurred while they came into contact with patients with tuberculosis. Therefore, infection control programs should be directed at preventing work-related tuberculosis among HCWs. Scrub typhus accounted for more than half of all work-related infectious disease cases. Interestingly, the number of compensated cases of scrub typhus in
Discussion Our study shows higher numbers of compensated infectious diseases in Korea compared to earlier years5,6; tuberculosis, hepatitis, and scrub typhus remained the most-compensated infections in all studies. However, results differed from those in other countries. A surveillance program in UK (THOR)
Table 1 Distribution of characteristics of work-related infectious diseases in Korea by calendar year, N (%) 2006 Gender Male Female Age (years) 20–29 30–39 40–49 50–59 60# missing Employment duration (months) duration,3 3#duration,6 6#duration,12 12#duration,24 24#duration,36 36#duration,48 duration§48 Occupation Administrator Professionals and technicians Clerks Service workers Sales workers Skilled agricultural Craft and related trades workers Plant, machine operators and assemblers Unskilled laborers
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2007
2008
2009
2010
2011
Total
45(42.1) 62(57.9)
78(41.5) 110(58.5)
46(36.5) 80(63.5)
162(42.7) 217(57.3)
66(41.8) 92(58.2)
40(38.5) 64(61.5)
437(41.1) 625(58.9)
40(37.4) 23(21.5) 13(12.1) 19(17.8) 11(10.3) 1(0.9)
48(25.5) 30(16.0) 35(18.6) 46(24.5) 29(15.4) 0(0.0)
38(30.2) 26(20.6) 11(8.7) 23(18.3) 27(21.4) 1(0.8)
35(9.2) 38(10.0) 44(11.6) 98(25.9) 164(43.2) 0(0.0)
33(20.9) 28(17.7) 18(11.4) 30(19.0) 49(31.0) 0(0.0)
17(16.3) 17(16.3) 17(16.3) 12(11.6) 41(39.5) 0(0.0)
211(19.9) 162(15.3) 138(13.0) 228(21.5) 321(30.1) 2(0.2)
17(15.9) 8(7.5) 8(7.5) 18(16.8) 15(14.0) 13(12.1) 28(26.2)
35(18.6) 14(7.4) 41(21.8) 21(11.2) 11(5.9) 19(10.1) 47(25.0)
18(14.3) 12(9.5) 30(23.8) 18(14.3) 10(7.9) 9(7.1) 29(23.1)
78(20.6) 183(48.3) 49(12.9) 19(5.0) 9(2.4) 8(2.1) 33(8.7)
29(18.3) 42(26.5) 21(13.3) 24(15.2) 8(5.1) 5(3.2) 29(18.4)
32(30.8) 12(11.5) 15(14.4) 9(8.7) 9(8.7) 4(3.8) 23(22.1)
209(19.7) 271(25.5) 164(15.4) 109(10.3) 62(5.8) 58(5.5) 189(17.8)
1(0.9) 50(46.8) 4(3.7) 6(5.6) 2(1.9) 0(0.0) 6(5.6) 2(1.9) 36(33.6)
5(2.7) 61(32.4) 22(11.8) 1(0.5) 0(0.0) 5(2.7) 14(7.4) 1(0.5) 79(42.0)
1(0.8) 56(44.4) 2(1.6) 1(0.8) 1(0.8) 6(4.8) 9(7.1) 1(0.8) 49(38.9)
7(1.8) 49(12.9) 5(1.3) 7(1.8) 2(0.5) 9(2.4) 11(2.9) 0(0.0) 289(76.4)
7(4.4) 52(32.9) 5(3.3) 4(2.5) 1(0.6) 1(0.6) 1(0.6) 1(0.6) 86(54.5)
2(1.9) 37(35.6) 4(3.8) 0(0.0) 0(0.0) 0(0.0) 6(5.8) 4(3.8) 51(49.1)
23(2.2) 305(28.6) 42(4.0) 19(1.8) 6(0.6) 21(2.0) 47(4.4) 9(0.8) 590(55.6)
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Hepatitis A Hepatitis B Hepatitis C Hepatitis E Influenza A/H1N1 Hemorrhagic Fever with Renal Syndrome Chicken pox Dengue fever Epidemic keratoconjunctivitis Bacterial Scrub typhus Mycobacterium tuberculosis{ Lung Bronchus Pleura Lymph node Meningitis Intestine or peritoneum Spine Breast Food poisoning, gastroenteritis Typhus Para-typhus Shigella species Other Brucellosis Streptococcus species Clostridium Vibrio vulnificus Leptospirosis Q fever Legionella Listeria Parasite Scabies Malaria Plasmodium vivax Plasmodium palcifarum Plasmodium Ovale & malariae Fungal Tinea
Viral Hepatitis
Causes
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0.0 0.4 0.2 0.2 0.0
0 5 2 3 0 0.1
2.9 3.3 2.9 0.2 0.2 0.2 0.0 0.0 0.0 0.0 0.2 0.0 0.0 0.0 0.2 0.4 0.0 0.1 0.0 0.0 0.0 0.0 0.0
36 42 36 2 2 3 0 0 0 0 3 0 0 0 2 5 0 1 0 0 0 0 0
1
0.4 0.2 0.1 0.1 0.0 0.0 0.5 0.1 0.1 0.0
Claim rate*
5 3 1 1 0 0 6 1 1 0
N
2006
5
7 6 5 0 1
74 58 47 1 5 9 1 2 0 0 17 0 0 15 2 0 4 0 2 0 0 0 1
8 0 2 6 0 0 5 0 0 0
N
Table 2 Work-related infectious diseases in Korea by calendar year
0.4
0.5 0.5 0.4 0.0 0.1
5.7 4.5 3.6 0.1 0.4 0.7 0.1 0.2 0.0 0.0 1.3 0.0 0.0 1.2 0.2 0.0 0.3 0.0 0.2 0.0 0.0 0.0 0.1
0.6 0.0 0.2 0.5 0.0 0.0 0.4 0.0 0.0 0.0
Claim rate*
2007
0
1 2 1 1 0
56 40 32 1 5 3 1 0 1 0 3 1 0 0 2 1 1 0 0 1 0 0 0
16 7 0 9 0 0 2 3 0 0
N
0.0
0.1 0.2 0.1 0.1 0.0
4.2 3.0 2.4 0.1 0.4 0.2 0.1 0.0 0.1 0.0 0.2 0.1 0.0 0.0 0.2 0.1 0.1 0.0 0.0 0.1 0.0 0.0 0.0
1.2 0.5 0.0 0.7 0.0 0.0 0.2 0.2 0.0 0.0
Claim rate*
2008
1
9 4 3 0 1
276 29 24 1 1 2 1 0 1 0 4 1 2 0 1 1 1 1 0 0 1 1 0
9 8 0 1 0 26 13 2 1 0
N
0.1
0.7 0.3 0.2 0.0 0.1
20.5 2.2 1.8 0.1 0.1 0.1 0.1 0.0 0.1 0.0 0.3 0.1 0.1 0.0 0.1 0.1 0.1 0.1 0.0 0.0 0.1 0.1 0.0
0.7 0.6 0.0 0.1 0.0 1.8 0.0 0.1 0.1 0.0
Claim rate*
2009
1
1 3 2 1 0
76 31 28 0 1 3 0 0 0 1 1 0 0 0 1 1 1 1 0 0 0 0 0
10 2 0 7 1 26 5 1 0 0
N
0.1
0.1 0.2 0.1 0.1 0.0
5.4 2.2 0.2 0.0 0.1 0.2 0.0 0.0 0.0 0.1 0.1 0.0 0.0 0.0 0.1 0.1 0.1 0.1 0.0 0.0 0.0 0.0 0.0
0.7 0.1 0.0 0.5 0.1 1.8 0.4 0.1 0.0 0.0
Claim rate*
2010
0
5 1 0 0 1
49 27 22 1 3 0 0 1 0 0 4 1 3 0 0 0 0 1 0 0 0 0 0
7 3 0 4 0 1 3 0 3 1
N
0.0
0.3 0.1 0.0 0.0 0.1
3.3 1.8 1.5 0.1 0.2 0.0 0.0 0.1 0.0 0.0 0.3 0.1 0.2 0.0 0.0 0.0 0.0 0.1 0.0 0.0 0.0 0.0 0.0
0.5 0.2 0.0 0.3 0.0 0.1 0.2 0.0 0.2 0.1
Claim rate*
2011
8(0.8)
23(2.1) 21(2.0) 13(1.2) 5(0.5) 3(0.3)
567(53.4) 227(21.4) 189 6 17 20 3 3 2 1 32(3.0) 3(0.3) 5(0.5) 15(1.4) 8(0.8) 8(0.8) 7(0.6) 4(0.4) 2(0.2) 1(0.1) 1(0.1) 1(0.1) 1(0.1)
55(5.2) 23(2.1) 3(0.3) 28(2.6) 1(0.1) 53(5.0) 34(3.2) 7(0.6) 5(0.5) 1(0.1)
Total n(%)
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0.0 0.0 0.1 7.1 *: Annual compensated work-related infectious disease claim rate per million {: duplication of sites was allowed. The number of denominator (thousand persons) at each year: (2006) 12,546; (2007) 12,995; (2008) 13,245; (2009) 13,459; (2010) 14,198; (2011) 14 700.
0 0 2 104 0.0 0.0 0.0 11.1 0 0 0 158 0.0 0.0 0.0 28.2 0 0 0 379 0.0 0.0 0.0 9.5 0 0 0 126 0.0 0.1 0.0 14.5 0 1 0 188 1 0 0 107 Others Cellulitis Subcutaneous abscess Pneumonia Total
0.1 0.0 0.0 8.5
Claim rate* N Causes
Claim rate*
N
Claim rate*
N
Claim rate*
N
Claim rate*
N
Claim rate*
N
2011 2010 2009 2008 2007 2006 Table 2 Continued 348
1(0.1) 1(0.1) 2(0.2) 1,062(100.0)
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Total n(%)
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2009 was much higher than in other years (n5365, 64.4%). To understand the reason for this epidemic, it was important to identify the occupation that accounted for this spike in scrub typhus incidence. To overcome the effects of the global recession, which began in late 2008, the Korean government hired approximately 250,000 and 100,000 short-term contract workers in 2009 and 2010, respectively.12–14 Workers aged 60 years or over accounted for 47.9% and 57.2% of participants in 2009 and 2010, respectively.12 In the present study, the mean age of scrub typhus cases was 60.2 years and the most common tasks for these workers were outdoor activities for forestry and park care for local governments. Thus, public programs for creating jobs may have accounted for an epidemic of workrelated scrub typhus. Government administrators should consider these results as important side-effects of their policies and clinicians should also closely observe the patterns of epidemics in work-related infectious diseases and prevent them from epidemics through education initiatives. Work-related viral hepatitis, such as hepatitis B and C, was common among HCWs.5,6,15 It is well known that nurses and interns are most vulnerable to needle stick injury (NSI); incidence of NSI (incidence/ 100 persons/year) in Korea was 5.22 for nurses and 29.52 for interns,16 which is consistent with the results of previous reports and our finding that addition to nurses, interns were more susceptible to work-related viral hepatitis from NSI than any other clinicians (residents and faculty) and other HCWs. Thus, further management for prevention and evaluation is needed for the most vulnerable HCWs, particularly interns and nurses. The number of hepatitis B cases was smaller than that of hepatitis C cases, likely because hepatitis B has been regulated by the national vaccine schedule since 1995, whereas hepatitis C has not.17,18 It seems that workers who experienced NSI according to hepatitis B, i.e. young generation who had undergone hepatitis B immunization might not claim for HBV.1 However, those who experienced NSI resulting in hepatitis C were required to undergo the post-NSI care program covered by the IACI. This may be responsible for small number of hepatitis B being reported in IACI compared to hepatitis C. In this study, hepatitis A was compensated more frequently than hepatitis B (Table 2). Comparing our data to a previous study,5 the number of workers compensated for contracting work-related hepatitis A increased from 1 in 2001–2003 to 23 in 2006–2011. One of reason for this is an increase of hepatitis A infection in the general population (reported cases by surveillance system; 105 in 2001 and 13,559 in 2009).1 Anti-hepatitis A (HAV) seroprevalence may play an important role in
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Table 3 Work-related infectious disease in Korea from 2006 through 2011 by standard occupation Standard occupation Causes Viral Hepatitis Hepatitis Hepatitis Hepatitis Hepatitis
A B C E
Influenza A/H1N1 Hemorrhagic fever with renal syndrome Chicken pox Dengue fever Epidemic keratoconjunctivitis Bacterial Scrub typhus Mycobacterium tuberculosis Food poisoning, gastroenteritis Typhus Para-typhus Shigella species Other Brucellosis Streptococcus species Clistrideum Vibrio vulnificus Leptospirosis Q fever Legionella Listeria Parasite Scabies Malaria Fungal Tinea Others Cellulitis Subcutaneous abscess Pneumonia Total
A
B
C
D
E
F
G
H
I
Total n(%)
0 0 0 0 0 9 2 0 0 0
43 12 2 28 1 28 1 6 1 1
2 1 1 0 0 9 1 0 0 0
0 0 0 0 0 0 0 0 0 0
1 1 0 0 0 1 1 0 1 0
0 0 0 0 0 0 1 0 0 0
5 5 0 0 0 1 2 1 0 0
0 0 0 0 0 0 2 0 3 0
4 4 0 0 0 5 24 0 0 0
55(5.2) 23(2.1) 3(0.3) 28(2.6) 1(0.1) 53(5.0) 34(3.2) 7(0.6) 5(0.5) 1(0.1)
0 1 3 0 2 0 1 0 1 0 1 0 0 0 1
10 204 3 1 0 0 2 0 2 0 0 0 0 0 0
3 3 19 2 1 15 1 0 0 0 0 0 0 0 0
0 6 0 0 0 0 0 6 0 0 0 0 0 0 0
0 0 2 0 1 0 1 0 0 0 0 0 0 0 0
20 0 0 0 0 0 0 0 0 0 0 0 0 0 0
21 4 1 0 1 0 0 1 1 2 0 1 0 0 0
2 0 2 0 0 0 2 0 0 0 0 0 0 0 0
511 9 2 0 0 0 2 1 3 2 1 0 1 1 0
567(53.4) 227(21.4) 32(3.0) 3(0.3) 5(0.5) 15(1.4) 9(0.8) 8(0.8) 7(0.6) 4(0.4) 2(0.2) 1(0.1) 1(0.1) 1(0.1) 1(0.1)
0 4
3 2
0 2
6 1
0 0
0 0
0 7
0 0
14 5
23(2.1) 21(2.0)
1
0
1
0
0
0
0
0
6
8(0.8)
0 0 0 23
0 0 2 306
0 1 0 41
0 0 0 19
0 0 0 6
0 0 0 21
0 0 0 47
0 0 0 9
1 0 0 590
1(0.1) 1(0.1) 2(0.2) 1,062(100.0)
A: Administrator; B: Professionals and technicians; C: Clerks; D: Service workers; E: Sales workers; F: Skilled agricultural; G: Craft and related trades workers; H: Plant and machine operators and assemblers; I: Unskilled laborers.
explaining this change. Based on a Korean longitudinal study on HAV seroprevalences in children and adolescents over two decades, the rates decreased (a
similar decrease was not found in the older generation).19,20 These results are consistent with ours showing that an age of workers compensated for hepatitis A
Table 4 Distribution of infectious diseases among health care workers by job Viral hepatitis Tuberculosis Job title Nurse Medical laboratory technologist Clinician Nurse’s aide Commercial caregiver Dental technician Radiology technician Others Total
A
B
C
Total
Influenza
Scabies
Chicken pox
Others
Total
n(%)
n
n
n
n(%)
n(%)
n(%)
n(%)
n(%)
n(%)
150(72.5) 14(6.8)
5 1
2 0
25 0
32(74.4) 1(2.2)
8(33.3) 5(20.8)
0(0.0) 0(0.0)
1(20.0) 0(0.0)
3*(100.0) 0(0.0)
194(66.2) 20(6.9)
12(5.8) 11(5.3) 2(1.0) 2(1.0) 6(2.8) 10(4.8){ 207(100.0)
1 2 2 2 0 0 13
0 0 0 0 0 0 2
2 1 0 0 0 0 28
1(4.2) 3(7.0){ 3(7.0) 0(0.0) 2(4.7) 0(0.0) 2(4.7) 4(16.7) 0(0.0) 1(4.2) 0(0.0) 5(20.8)1 43(100.0) 24(100.0)
0(0.0) 0(0.0) 11(100.0) 0(0.0) 0(0.0) 0 11(100.0)
2(40.0) 2(40.0) 0(0.0) 0(0.0) 0(0.0) 0(0.0) 5(100.0)
0(0.0) 0(0.0) 0(0.0) 0(0.0) 0(0.0) 0(0.0) 3(100.0)
18(6.1) 16(5.5) 15(5.1) 8(2.7) 7(2.4) 15(5.1) 293(100.0)
*: 2 of pneumonia, 1 of epidemic keratoconjunctivitis. { Interns (n53). { Physical therapist (n52); electromyogram technician (n51); electrocardiogram technician (n51); emergency aid worker (n51); sterilization room worker (n51); hospital coordinator (n51); security officer (n51); office worker (n51); laundry worker (n51). 1 Unskilled laborer (n52); cleaner (n51); office worker (n51); social worker (n51).
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(n523) was 29.8 years (SD¡4.1) (data not shown). Therefore, hepatitis A vaccination should be encouraged in young workers. Business travel-related infections emerged between 2006 and 2011. In addition to Korea when an endemic of malaria caused by Plasmodium vivax occurred, workers receiving compensation for malaria caused by P. falcifarum and P. ovale might be due to international business travel-related infection.1 Workers compensated for hepatitis E, dengue fever, and Q fever were also related to international business travel in KCOMWEL investigation data. Clinicians should provide business travelers with proper precautions and vaccinations and administrators should educate and inform workers planning international business travels on the available prevention methods. As explained previously, the IACI covered 57.4% of the economically active population in 2010. This is one of the main limitations of this study. The IACI did not cover professional soldiers, so we might have underestimated the actual numbers of work-related occupational diseases, such as scrub typhus, tuberculosis, and hemorrhagic fever with renal syndrome by Hanta or Seoul virus.4 A total of 651 cases of brucellosis were reported by the KCDC between 2001 and 2010.21 In a review of farmers’ diseases, the cases of reported brucellosis increased from 0 in 2001 to 101 in 2007.22 Work-related brucellosis may be underestimated in our study. This is because selfemployed workers (including farmers) were not covered by the IACI. All of the compensated brucellosis cases in this study were contract workers; therefore, these results should be carefully interpreted. In addition, IACI only covered cases with 3 days and more of recuperation. This may also have led to under-reporting (cases of work-related infectious diseases, such as travelers’ diarrhea treated with simple hydration or 1-day rest and tinea infection). In spite of these limitations, our study has some strengths. It accessed data from the electronic database of cases submitted to the KCOMWEL. Also, work-relatedness was evaluated by KCOMWEL’s physician or a panel of clinicians, including occupational physicians and other specialists. In some cases, work-relatedness was evaluated after an epidemiologic investigation by the Occupational Safety and Health Research Institute (OSHRI) was carried out. Therefore, this data could provide accurate information on the relationship between occupation/task and the onset of infection. We can also understand the longitudinal distribution of work-related infectious diseases in Korea. This study provided administrators with valuable information on prevention strategies for workrelated infectious diseases in several vulnerable working groups, such as HCWs and short-term contractors in public sector. In conclusion, all information obtained in
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this study will be useful for clinicians to explain reasons for several work-related infectious disease endemics and to establish good strategies to prevent them.
Conflict of Interest The authors state that they have no competing financial interests to declare.
Acknowledgements No acknowledgements
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