814 THE STATUS OF POLIOMYELITIS IN NEW YORK CITY PASCAL JAMES INIPERATO, M.D., M.P.H. & T.M. First Deputy Commissioner City of New York Department of Health New York. N.Y.
p OLIOMYELITIS was once an important public health problem in New York City. After the introduction of inactivated poliovirus (Salk) vaccine in i955 and live oral poliovirus (Sabin) vaccine in i961 there was a dramatic decrease in the number of clinical cases reported in New York City. Although excellent control has been achieved in the city, sporadic cases still occur. The purpose of this study is to review the pattern of the disease in New York City during the 24 years from i95i through 1974 and to present in detail its causes between i96i and 1974. METHODS The morbidity and mortality data received by the Department of Health between i95i and I974 were reviewed. While most diseases are under-reported in New York City, poliomyelitis in general has been reported fairly accurately when diagnosed. The disease was brought under control in the city through vaccination by both the public and the private medical sectors. As with many immunization efforts, the public sector has had to bear most of the responsibility for immunizing children from low-income families. Poliomyelitis immunization programs have been planned and executed by several bureaus within the Department of Health, including the Bureau of School Health, the Bureau of Maternal and Child Health, and the Bureau of Infectious Disease Control. The continuing efforts of the Department of Health to control poliomyelitis in the city will be reviewed in
detail. RESULTS Figure i shows the number of cases of poliomyelitis reported an-
nually in New York City from i95i through 1970. During this period Bull. N. Y. Acad. Med.
8I5
POLIOMYELITIS IN NEW YORK CITY - -
co 0)
co L-
0)
co co
CD 0)
LO LC)
CV)
Ln
o
%
to
cn
UV3,k H3 S3SVO :1O 383wnN
Vol. 52, No. 7, September 1976
C4
-
8i6
P. J. IMPERATO
TABLE I. ANNUALLY REPORTED CASES OF POLIOMYELITIS BY AGE. NEW YORK CITY, 1961-1974* Less than 5 yrs. 5-9 yrs. 10-14 yrs. 15+ yrs. Total Year Number Rate Number Rate Number Rate Number Rate Number Rate
1951 1952 1953 1954, 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974
159 164 167 241 231 43 23 52 85 49
24 24 25 36 35 6 3 8 12 7
1
+ +
3
172 284 227 285 236 42 18 19
45 23 1 4 1 1
30 49 38 46 37 7 3 3 7 4
103 153 119 138 132
23 33 24 28 26
18
3
6 8 8 4
1 1 1 1
121
220 164 180 207 46 10 21 32 16
+
2 3 3 3 3 1
+
555 821 667 844 806 149 57 100 170 92 2 7 1
2 0 0
1
1 1
1 1
7 10 9 11 10 2 1 1
2 1
+ + +
+
0 0 0
1
1
0 0
*Numbers and rates per 100,000 - = zero cases and zero rate + = few cases, low rate
the largest number of cases occurred in 1954, when 844 cases were reported. The annual incidence that year was i I per i00,000 residents. A sharp decline in the annually reported number of cases occurred in 1956, when 149 cases were registered. There was an increase again in 1959, when 170 cases were reported, with an annual incidence of two per i00,000 residents. In i96i there was a precipitous decline to two cases. Since that time only sporadic cases of the disease have been reported. During the I4 years from i96i through I974 only 15 cases of the disease were reported in New York City, the last in 1972. During the period from 195I through 1974, 4,286 cases of poliomyelitis and 207 deaths were reported. The average annual case-mortality rate for this period varied from a minimum of 3.3 per i00 cases Bull. N. Y. Acad. Med.
./f
8l7
POLIOMYELITIS IN NEW YORK CITY
\E
0
0
(D 0)
a) a)
If)
(U)0)
-m
U0)
0~~~~~~~~~~~~~~)o
E
0/
0o
40
10.
to
UIn
N
0~
- q
"4*~
°S
.edv~~d jo.A aoi~olndod Jots uo~oindod
0 If)
Vol. 52, No. 7, September 1976
t A% Or
_~~~~~~~~~~~~~~~~~~~~~'
H) 0001001 OOO'X lied J~0) P4S
e
8 I 8
P.
J. IMPERATO
TABLE II. POLIOMYELITIS BY AGE GROUP AND SEX. NEW YORK CITY, 1961-1974
Age group
Number
Male
Female
%
Less than 5 5-9 10-14 15+
4 7 1 3
2 3 1 2
2 4 1
26.7 46.7 6.6 20.0
15
8
7
100.0
Total
TABLE III. REPORTED CASES OF POLIOMYELITIS BY ETHNIC GROUP. NEW YORK CITY, 1961-1974 Cases
Ethnic group
(No.)
%
Rate*
White Nonwhite Puerto Rican Other
7 5 2 1
46.7 33.3 13.3 6.6
0.13 0.27 0.22 0.20
15
100.0
0.18
Total
*Per 100,000 population.
in 1956 to a maximum of I2.3 per i00 cases in 1959. Table I shows the number of cases of poliomyelitis reported annually from I951 to 1974. Figure 2 shows the reported incidence rates for the less-than-five-year and the five-to-nine-year age groups from 195I to i960. In most years the highest age-specific incidence rates occurred in the five-to-nine-year age group and the next highest rates in the less-than-five-year group. Between 1955 and 1957 the incidence rates for these two groups were similar. Between I957 and i960 rates for the less-than-five-year age group were higher than for the five-to-nineyear age group. Between 195i and i960 the lowest rates were observed in adults more than I years of age. The highest age-specific rate occurred in 1952 in the five-to-nine-year age group, when 49 cases per i00,000 population were recorded. Table II shows the distribution of cases by age group from i96i to 1974. The largest percentage occurred in the five-to-nine-year age Bull. N. Y. Acad. Med.
POLIOMYELITIS IN NEW
YORK
CITY
8I9
TABLE IV. REPORTED CASES OF POLIOMYELITIS BY BOROUGH. NEW YORK CITY, 1961-1974 Borough
Manhattan Brooklyn Queens Bronx Staten Island Total
Number
%
5 4 1 4 1
33.3 26.7 6.6 26.7 6.6
15
100.0
group (46.7%) and the next largest in the less-than-five-year group (26.7%). Since i967 three cases of poliomyelitis have been reported, all in adults, representing a shift in the age-group distribution of the disease. Of the 15 cases, eight occurred among males and seven among females (Table II). The male-to-female ratio was i.i. Table III shows the distribution of the IS cases by ethnic group. Although 46.7% of all cases occurred among whites, the incidence rate for this group was the lowest, 0.13 per iooooo population. The highest rate was among nonwhites, 0.27 cases per rootooo population. The over-all rate for all groups in New York City during this period was o.i8 per ioo,ooo population. Table IV presents the distribution of cases by borough of report. The smallest percentage of cases was reported from Queens and Staten Island, the highest from Manhattan. From i96i to [974 four cases occurred in July, three in August, and one each in April, June, September, October, and December. Three cases occurred in February. Ten of the IS reported cases were distributed throughout the classical summer-fall peak period. Type-specific etiology is determined by viral isolation or a diagnostic (fourfold) rise or fall in serotype-specific antibody titer, or both. Table V presents the diagnostic laboratory data on the 15 cases that occurred during this period. Six cases (4o%) were of Type I, six cases (40%) of Type III, and three cases (zo%) of Type II. In io cases the poliomyelitis virus was isolated, and in all cases serologic diagnosis was made by the complement-fixation test, the neutralization test, or both. Of the I5 patients, 14 (934%) had paralytic disease with residual Vol. 52, No. 7, September 1976
8 2 08zo
P. J. IMPERATO P.J MPR
~~
03
0
C
--
-
LI
O
-D O
a) 9
o
o
-
W
w
1+ till
0
0 0l-
Iz +
+ I+
w
0
W
0
I +
0A
111
+
+
+ + +
+
00 rTJ
o Q
+
o IQ to
I
+
oCi 0 0n
Lz.~
z
O
+++
+
++
+
+
++I
+
+++
+
Bull. N. Y. Acad. Med.
POLIOMYELITIS IN NEW YORK CITY
82 I
TABLE VI. TYPE OF RESIDUAL PARALYSIS OF REPORTED CASES OF POLIOMYELITIS. NEW YORK CITY, 1961-1974 Cases
Type of paralysis Bulbar
(No.)
%
Spinal Bulbospinal
0 10 4
71.4 28.6
Total
14
100.0
0
TABLE VII. CLINICAL STATUS OF PATIENTS WITH POLIOMYELITIS 60 DAYS AFTER ONSET. NEW YORK CITY, 1961-1974 Status
Never paralyzed Complete recovery Minor involvement Significant disability Severely disabled
Total
Cases
%
1 1 2 4 7
6.6 6.6 13.4 26.7 46.7
15
100.0
paralysis. Only one patient (6.6 %) did not have paralytic disease. Table VI presents data on the type of residual paralysis present in the I4 paralytic cases. The majority, IO patients (71.4%), had spinal paralysis; the remaining four (28.6%) had bulbospinal paralysis. All cases were evaluated for clinical status 6o days after the onset of the disease (Table VII). Seven of the 15 patients (46.7%) were severely disabled, four (26.7%) had significant disability, and two 03.4%) had minor involvement. Only one patient with paralytic disease made a complete recovery. None of the 15 patients observed during this period had received live oral or inactivated poliovirus vaccine within four to 3o days before the onset of paralysis. Among those who had received either partial or complete immunization prior to the onset of illness, such immunizations had been given from six months to several years before the onset of the disease (Table IX). In two cases there had been close contact with a family member Vol. 52, No. 7, September 1976
82
P. J. IMPERATO
2
s: p:
s&
Co
s
cn
x
-i
-t
=1
m
n It
-3
CD
o1
.XI
CI 9
Ciit
C5
cc
to
ci
ci3 tt
cc
C
14
cc
C
n
ev
='
3
ct
C
=
e--
C-t -
&
_ ;T
c_.
md
o~ ~ ~ :r
~
> C)
C-
ic
O
CK;
CI
C CR
C
C
1-3
lct -1
-:
c4;
LI.
Iz
:r
..-
_..A
ci
_i
Q
0-
Erl m
In-
cn I-
_.01
I
-w
11J
;¢17
_.
6 -t
3
ON _.
cc
c-
ci
C-
CZ
bo
Co
cnoxcnt
eo o
-4
LM -
4
00
_''
w
o-
C;ic io UL Oz
I.
0
O~ ~-.
-C M
m-
W
v7
c
w
;
O-;-
Bull. N. Y. Acad. Med.
82 3
POLIOMYELITIS IN NEW YORK CITY
TABLE IX. IMMUNIZATION HISTORY OF CASES OF POLIOMYELITIS. NEW YORK CITY, 1961-1974 Cases (No.) 15
15
*Four
Complete* ?? complete Iniactivated polioviru.s vacc~ne (Salk) 4
5
None 6
Live oral poliovirus vaccine (Sabin) 0 3
12
or more doses of Salk vaccine; three or more doses of Sabin vaccine
who had received live oral poliovirus vaccine four to 6o days before the onset of illness. The first case (I967) was in a 3i-year-old white male whose son, aged seven months, had received a second dose of trivalent oral poliovirus vaccine 27 days before the onset of the father's illness. The second case (i968) was in a 3o-year-old black female whose four-month-old daughter had received a dose of trivalent oral poliovirus vaccine IO days before the mother's illness began. Both of these infections were with poliovirus Type II. IMMUNIZATION LEVELS
During July and August I972 the immunization program of the Bureau of Infectious Disease Control of the Department of Health undertook a random survey of households in 14 health districts of the city. Nine of these districts were considered poverty areas and five nonpoverty areas. Information was obtained on I,9I8 children less than ii years of age. Of these, I,748 (9I.o %) had received partial or complete immunization against poliomyelitis with inactivated or live oral poliovirus vaccine. However, the proportion of children who had received complete immunization (Table VIII) varied from a minimum of 4.7%0 in Jamaica East to a maximum of 77.8% in Sunset Park. In only four of the I4 districts surveyed-Fordham-Riverdale, Jamaica IVest, Richmond, and Sunset Park-were more than 6o% of children less than I I years of age fully immunized. Immunization levels among six-to-Io-year-old children were dramatically higher than those among one-to-five-year-old children for all districts. In large measure this is attributable to the fact that many children are immunized by the staff of the Department of Health's Bureau of School Health once they enter the school system. But even in the six-to-io-year age group there Vol. 52, No. 7, September 1976
824
P.
824
IMPERATO
J.
IMPERATO
POLIO I POLIO 11 _________. ___ POLIOIII * * * * *. -S S 0
100T
--I---.-
.,O..
--
0 0 0
80 0
0 0
0
a
0
O' 0
-
*
0
0
..'s
0
"
-O-
0
0 ,O-
"
0
O--
s-
O
O- -0
.,O- 0.
60+ z 0 w
a-
40+_
20 ±
n Iv vJ
, 1
2
3 AGE IN YEARS
4
5
6-7
Fig. 3. Percentage of each age group protected against polio I, polio 11, and polio III. 1,200 children tested in poverty areas of four boroughs of New York City Brooklyn, Bronx, Manhattan, and Queens in 1971.
such as Jamaica East, Bedford, and Central Harlem in which immunization levels remain extremely low, ranging from 8.oO to 38.1%. In 1972 the New York State Department of Health and the New York State Department of Education conducted a statewide survey for levels of immunity to diphtheria, poliomyelitis, measles, and rubella among children entering school.' In New York City questionnaires were certain poverty areas
i,251 schools, of which
responded. Of these, 270 were private schools and 265 were public. Information was collected on 49,408 entering students, of whom 66% were found to be fully
were sent to
535
Bull. N. Y. Acad. Med.
POLIOMYELITIS IN NEW YORK CITY
825
immunized against poliomyelitis. During this survey, the term "fully immunized" was employed to mean the receipt of three or more doses of either live or inactivated poliovirus vaccine. Of the I4,530 children entering private schools in New York City, 11,470 (79%0) had been fully immunized, whereas of the 34,878 children entering public schools only 20,881 (60%) had been fully immunized. In 1971 the sera of I,200 children from the poverty areas of four boroughs of New York City-Brooklyn, Bronx, Manhattan, and Queens-were tested by the New York City Department of Health for neutralization antibodies to poliovirus Types I, II, and III (see Figure 3). The sera also were being screened for levels of lead. Among children one year of age, protective antibodies were present against Type I poliovirus in 78%, against Type II in 88.5%, and against Type III in 74%. Among children three years of age, 92% had antibodies to Type I, 98% to Type II, and 8o% to Type III. Among children six to seven years of age, 92%0 demonstrated protective antibodies against Type I, 98.5% against Type II, and 88.5% against Type III. These data show much higher levels of protection in poverty areas than those surveys which recorded vaccination histories. Since wild poliovirus types are now rare in the United States, these children probably developed their protective antibodies in response to infection with vaccine virus acquired from vaccinated contacts. DIscussIoN Poliomyelitis was once a serious epidemic disease in New York City. Since the beginning of this century true major outbreaks occurred in the city in I9I6, I931, I935, I944, and I949.- In 1949, 2,446 cases and 179 deaths (73%) were recorded. Between these outbreaks large numbers of cases occurred. This long-standing pattern did not change until I955, when inactivated poliovirus (Salk) vaccine was first used widely in New York City. The vaccination of large numbers of persons led to a precipitous fall in the annual incidence of the disease. This downward trend was augmented by the introduction of live oral poliovirus (Sabin) vaccine in i96i. Use of the two vaccines resulted in the elimination of large pools of susceptible individuals. In spite of the widespread use of the poliovirus vaccines since i96i, sporadic cases of poliomyelitis have continued to occur. During the 14 years from i96i to 1974, when live oral poliovirus vaccine has been Vol. 52, No. 7, September 1976
8 2. 6 826
P.
J.
IMPERATO
used, 15 cases of poliomyelitis occurred. Of these, 73.4% occurred in children less than I5 years of age. This proportion of cases usually occurred in this age group when poliomyelitis was epidemic in the city. Since I970 only one case has occurred in New York City. An annual average of 2I.5 cases occurred in the United States since I970.3 Nationally, poliomyelitis is still on the decline, only I4 cases occurring in 1973-the lowest annual figure yet recorded.3 There is much variation in the death rate from poliomyelitis. In the United States in recent years the death rate has varied from a low of 6.o% in I970 to a high of 2 I.o% in 1973. Among the I cases which occurred in New York City since 196I, the death rate was 33.3%. For reasons which are not fully understood, males are more commonly affected by poliomyelitis than females.4 The male-to-female ratio in New York City since i96i has been i. i, somewhat less than the ratios observed in the prevaccination era. Differences in race-specific incidence rates for poliomyelitis are not consistent nationally.3 It is thought that these incidence rates are affected by other factors, since it has been noted that they vary so widely from one epidemic period to another and from one endemic period to another.3 Although whites accounted for 46.7% of all cases reported since i96I, they had the lowest incidence of any group (Table III). This is probably a reflection of the much higher immunization levels found among whites (Table VIII). Only two of the Is cases reported in this period occurred in the boroughs of Queens and Staten Island, which are composed largely of white, middle-class neighborhoods where immunization levels are high. The classic summer-fall peak has not been observed nationally since the early i960s. Rather, cases have occurred throughout the year.' In New York City cases in the early i960s occurred for the most part in the summer and fall. However, the last two reported cases (i968 and 1972) occurred during the winter. The etiologic poliovirus was Type I in 40% of the cases, Type III in another 40% of the cases, and Type II in 20% of the cases. Nationally, there has been great variability from year to year in these proportions. In 1973, 43% of the I4 cases reported were due to multiple poliovirus types. These cases represent infections caused by vaccine virus and are classified as vaccine-associated cases. Prior to 1971 multiple poliovirus types were not observed as causes of the disease.3 Bull. N. Y. Acad. Med.
POLIOMYELITIS IN NEW YORK CITY
827
Paralytic poliomyelitis has been observed to occur both in recipients of oral poliovirus vaccine and in their close contacts within 6o days of vaccination.5 Between i963 and 1970 approximately 147 million doses of trivalent oral poliovirus vaccine were distributed in the United States. During this period nine cases of vaccine-associated paralysis occurred in recipients and 2 I cases in contacts of recipients.5 The risk of the disease occurring in vaccine recipients is o.o6 per million doses of vaccine distributed, and among contacts of vaccine recipients it is 0.I4 per million doses distributed. In New York City two cases of poliomyelitis occurred among contacts of vaccine recipients. In the United States in I973 nine cases (64%) of poliomyelitis were vaccine-associated. Of these, four occurred among contacts of vaccine recipients. Cases among vaccine recipients continue to occur, however, among both adults and children, since both have contact with vaccine recipients. A number of cases of poliomyelitis have been found among vaccine recipients who after vaccination were recognized as having immunodeficiency disorders.3 Clinically, most of the patients with the disease in New York City since i96i (73.%) have been left seriously disabled. This pattern also has been observed nationally.3 Thus, once the diagnosis of paralytic poliomyelitis is made, the likelihood is great that the individual will be left with significant residual paralysis. Since I964 routine immunization of adults against poliomyelitis has been curtailed. The emphasis since that time has been on the routine immunization of infants. Every year an appraisal of the immunization status of the population is undertaken by the United States Public Health Service. This is assessed through a sample survey of the history of the types and number of doses of vaccine received.3 This form of survey is less satisfactory than a serologic survey. In 1973 the United States Immunization Survey revealed that only 60.4% of those in the one-to-four-year age group had received three or more doses of oral poliovirus vaccine.3 A survey of the same kind, conducted in New York City in 1972, revealed that in the one-to-five-year age group complete immunization varied from 1.3% in Jamaica East to 6z.7% in Staten Island (Table VIII). A survey of children entering school in 1972 in New York City revealed that 66% had received complete immunizations. Levels of immunization were found by history to be lowest in inner-city poverty areas among blacks and Puerto Ricans, the Vol. 52, No. 7, September 1976
828
P. P.
J. J.
IMPERATO
two groups who since i96i have had the highest race-specific incidence rate for the disease. However, in sharp contrast to this are the results of the serologic survey referred to earlier and illustrated in Figure 3. This survey, whose results are much more accurate than those of a survey of immunization history, indicates that high levels of immunity to all three poliovirus types exist among young children in New York City's innercity poverty areas. It is probable that slightly higher levels of immunity exist among young children in the middle-income areas of the city, where most children are routinely immunized. Crowding and poor levels of personal hygiene and environmental sanitation help to propagate vaccine virus from vaccine recipients in inner-city areas to their contacts. In view of the low percentage of young children in inner-city areas who have a history of receiving poliomyelitis vaccine, these demonstrated high levels of immunity mean that a significant proportion of these children acquire immunity through the ingestion of vaccine virus excreted by recipients of vaccine. It is possible also that a proportion of those interviewed gave poor histories, stating incorrectly that, children had not been immunized. In middle-income areas of the city, where levels of personal and environmental hygiene are higher, the transfer of vaccine virus from recipients to contacts probably occurs with much less frequency. The emphasis of current immunization programs in New York City is on the vaccination of infants and small children. The Department of Health, through its Bureau of Child Health, School Health, and Infectious Disease Control has made special efforts to raise levels of immunity throughout New York City by means of immunization programs conducted in health centers, child-health stations, pediatric treatment centers, and schools. Although these programs have reached fewer than the optimal number of children, levels of immunity to poliomyelitis in the city are quite high in young children, as demonstrated by the department's serologic survey in inner-city poverty areas. Estimations of group immunity to poliomyelitis, based on analysis of the numbers of doses of vaccine distributed in a given geographic area and on surveys for vaccination history, are often erroneous. The transfer of vaccine virus from vaccinated persons to their contacts can be efficient, especially in the poor hygienic environment of the inner city. It results in a high level of group immunity which is not reflected Bull. N. Y. Acad. Med.
POLIOMYELITIS IN NEW YORK CITY
82 9
in interview surveys. The results of such interview surveys therefore must be interpreted cautiously. To date, the dire predictions based upon such surveys have not materialized. This is additional evidence of the relatively high level of group immunity to poliomyelitis in the city. SUMMARY The epidemiology of poliomyelitis in New York City between i95i and 1974 has been described in detail. Since i96i paralytic poliomyelitis has been a rare, sporadic disease in New York City. The responsibility for the successful control of the disease is shared by both the private and the public health sectors. Immunization programs today aim at reaching the maximum number of infants and young children. Interview surveys conducted throughout the city have revealed extremely low levels of vaccination among young children in inner-city poverty areas, but serologic surveys in the same areas have demonstrated extremely high levels of immunity to all three poliovirus types. This disparity can be accounted for by incorrect responses to interviews and, more important, by the transfer of vaccine virus among children living in the crowded setting of the inner city, where levels of personal and environmental hygiene are poor. ACKNOWLEDGMENTS I wish to express my sincere thanks to Mr. Chih L. Hwa, Senior Statistician, Bureau of Health Statistics and Analysis, for his assistance in analyzing the data; to Mrs. Monique Daly for drawing the figures; and to Mr. Donald Biemiller, Project Coordinator, New York City Immunization Program, Center for Disease Control, U.S. Public Health Service, and his staff, for their efforts to control poliomyelitis in New York City. I also wish to thank Mrs. Earlene Price and Miss Debra Watson for typing the manuscript. REFERENCES mary 1973. Atlanta, Center for Disease 1. Immunization Levels In School EnterControl, 1975. ers, New York State, September, 197k 4. Top, F. H.: Communicable and InfecAlbany, N.Y., N.Y. State Dept. of tio71s Disease. St. Louis, Mosby, 1968. Health, 1973. 5. Immaonizatiot A4gainst Disease 19712. 2. Siegel, M., Greenberg, M., and Magee, M. C.: Poliomyelitis in New York City. Atlanta, Center for Disease Control, 1973. New York J. Med., 50:1119-23, 1950. 3. Poliomyelitis Surveillance, A nnual Sum-
Vol. 52, No. 7, September 1976
p OLIOMYELITIS was once an important public health problem in New York City. After the introduction of inactivated poliovirus (Salk) vaccine in i955 and live oral poliovirus (Sabin) vaccine in i961 there was a dramatic decrease in the number of clinical cases reported in New York City. Although excellent control has been achieved in the city, sporadic cases still occur. The purpose of this study is to review the pattern of the disease in New York City during the 24 years from i95i through 1974 and to present in detail its causes between i96i and 1974. METHODS The morbidity and mortality data received by the Department of Health between i95i and I974 were reviewed. While most diseases are under-reported in New York City, poliomyelitis in general has been reported fairly accurately when diagnosed. The disease was brought under control in the city through vaccination by both the public and the private medical sectors. As with many immunization efforts, the public sector has had to bear most of the responsibility for immunizing children from low-income families. Poliomyelitis immunization programs have been planned and executed by several bureaus within the Department of Health, including the Bureau of School Health, the Bureau of Maternal and Child Health, and the Bureau of Infectious Disease Control. The continuing efforts of the Department of Health to control poliomyelitis in the city will be reviewed in
detail. RESULTS Figure i shows the number of cases of poliomyelitis reported an-
nually in New York City from i95i through 1970. During this period Bull. N. Y. Acad. Med.
8I5
POLIOMYELITIS IN NEW YORK CITY - -
co 0)
co L-
0)
co co
CD 0)
LO LC)
CV)
Ln
o
%
to
cn
UV3,k H3 S3SVO :1O 383wnN
Vol. 52, No. 7, September 1976
C4
-
8i6
P. J. IMPERATO
TABLE I. ANNUALLY REPORTED CASES OF POLIOMYELITIS BY AGE. NEW YORK CITY, 1961-1974* Less than 5 yrs. 5-9 yrs. 10-14 yrs. 15+ yrs. Total Year Number Rate Number Rate Number Rate Number Rate Number Rate
1951 1952 1953 1954, 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974
159 164 167 241 231 43 23 52 85 49
24 24 25 36 35 6 3 8 12 7
1
+ +
3
172 284 227 285 236 42 18 19
45 23 1 4 1 1
30 49 38 46 37 7 3 3 7 4
103 153 119 138 132
23 33 24 28 26
18
3
6 8 8 4
1 1 1 1
121
220 164 180 207 46 10 21 32 16
+
2 3 3 3 3 1
+
555 821 667 844 806 149 57 100 170 92 2 7 1
2 0 0
1
1 1
1 1
7 10 9 11 10 2 1 1
2 1
+ + +
+
0 0 0
1
1
0 0
*Numbers and rates per 100,000 - = zero cases and zero rate + = few cases, low rate
the largest number of cases occurred in 1954, when 844 cases were reported. The annual incidence that year was i I per i00,000 residents. A sharp decline in the annually reported number of cases occurred in 1956, when 149 cases were registered. There was an increase again in 1959, when 170 cases were reported, with an annual incidence of two per i00,000 residents. In i96i there was a precipitous decline to two cases. Since that time only sporadic cases of the disease have been reported. During the I4 years from i96i through I974 only 15 cases of the disease were reported in New York City, the last in 1972. During the period from 195I through 1974, 4,286 cases of poliomyelitis and 207 deaths were reported. The average annual case-mortality rate for this period varied from a minimum of 3.3 per i00 cases Bull. N. Y. Acad. Med.
./f
8l7
POLIOMYELITIS IN NEW YORK CITY
\E
0
0
(D 0)
a) a)
If)
(U)0)
-m
U0)
0~~~~~~~~~~~~~~)o
E
0/
0o
40
10.
to
UIn
N
0~
- q
"4*~
°S
.edv~~d jo.A aoi~olndod Jots uo~oindod
0 If)
Vol. 52, No. 7, September 1976
t A% Or
_~~~~~~~~~~~~~~~~~~~~~'
H) 0001001 OOO'X lied J~0) P4S
e
8 I 8
P.
J. IMPERATO
TABLE II. POLIOMYELITIS BY AGE GROUP AND SEX. NEW YORK CITY, 1961-1974
Age group
Number
Male
Female
%
Less than 5 5-9 10-14 15+
4 7 1 3
2 3 1 2
2 4 1
26.7 46.7 6.6 20.0
15
8
7
100.0
Total
TABLE III. REPORTED CASES OF POLIOMYELITIS BY ETHNIC GROUP. NEW YORK CITY, 1961-1974 Cases
Ethnic group
(No.)
%
Rate*
White Nonwhite Puerto Rican Other
7 5 2 1
46.7 33.3 13.3 6.6
0.13 0.27 0.22 0.20
15
100.0
0.18
Total
*Per 100,000 population.
in 1956 to a maximum of I2.3 per i00 cases in 1959. Table I shows the number of cases of poliomyelitis reported annually from I951 to 1974. Figure 2 shows the reported incidence rates for the less-than-five-year and the five-to-nine-year age groups from 195I to i960. In most years the highest age-specific incidence rates occurred in the five-to-nine-year age group and the next highest rates in the less-than-five-year group. Between 1955 and 1957 the incidence rates for these two groups were similar. Between I957 and i960 rates for the less-than-five-year age group were higher than for the five-to-nineyear age group. Between 195i and i960 the lowest rates were observed in adults more than I years of age. The highest age-specific rate occurred in 1952 in the five-to-nine-year age group, when 49 cases per i00,000 population were recorded. Table II shows the distribution of cases by age group from i96i to 1974. The largest percentage occurred in the five-to-nine-year age Bull. N. Y. Acad. Med.
POLIOMYELITIS IN NEW
YORK
CITY
8I9
TABLE IV. REPORTED CASES OF POLIOMYELITIS BY BOROUGH. NEW YORK CITY, 1961-1974 Borough
Manhattan Brooklyn Queens Bronx Staten Island Total
Number
%
5 4 1 4 1
33.3 26.7 6.6 26.7 6.6
15
100.0
group (46.7%) and the next largest in the less-than-five-year group (26.7%). Since i967 three cases of poliomyelitis have been reported, all in adults, representing a shift in the age-group distribution of the disease. Of the 15 cases, eight occurred among males and seven among females (Table II). The male-to-female ratio was i.i. Table III shows the distribution of the IS cases by ethnic group. Although 46.7% of all cases occurred among whites, the incidence rate for this group was the lowest, 0.13 per iooooo population. The highest rate was among nonwhites, 0.27 cases per rootooo population. The over-all rate for all groups in New York City during this period was o.i8 per ioo,ooo population. Table IV presents the distribution of cases by borough of report. The smallest percentage of cases was reported from Queens and Staten Island, the highest from Manhattan. From i96i to [974 four cases occurred in July, three in August, and one each in April, June, September, October, and December. Three cases occurred in February. Ten of the IS reported cases were distributed throughout the classical summer-fall peak period. Type-specific etiology is determined by viral isolation or a diagnostic (fourfold) rise or fall in serotype-specific antibody titer, or both. Table V presents the diagnostic laboratory data on the 15 cases that occurred during this period. Six cases (4o%) were of Type I, six cases (40%) of Type III, and three cases (zo%) of Type II. In io cases the poliomyelitis virus was isolated, and in all cases serologic diagnosis was made by the complement-fixation test, the neutralization test, or both. Of the I5 patients, 14 (934%) had paralytic disease with residual Vol. 52, No. 7, September 1976
8 2 08zo
P. J. IMPERATO P.J MPR
~~
03
0
C
--
-
LI
O
-D O
a) 9
o
o
-
W
w
1+ till
0
0 0l-
Iz +
+ I+
w
0
W
0
I +
0A
111
+
+
+ + +
+
00 rTJ
o Q
+
o IQ to
I
+
oCi 0 0n
Lz.~
z
O
+++
+
++
+
+
++I
+
+++
+
Bull. N. Y. Acad. Med.
POLIOMYELITIS IN NEW YORK CITY
82 I
TABLE VI. TYPE OF RESIDUAL PARALYSIS OF REPORTED CASES OF POLIOMYELITIS. NEW YORK CITY, 1961-1974 Cases
Type of paralysis Bulbar
(No.)
%
Spinal Bulbospinal
0 10 4
71.4 28.6
Total
14
100.0
0
TABLE VII. CLINICAL STATUS OF PATIENTS WITH POLIOMYELITIS 60 DAYS AFTER ONSET. NEW YORK CITY, 1961-1974 Status
Never paralyzed Complete recovery Minor involvement Significant disability Severely disabled
Total
Cases
%
1 1 2 4 7
6.6 6.6 13.4 26.7 46.7
15
100.0
paralysis. Only one patient (6.6 %) did not have paralytic disease. Table VI presents data on the type of residual paralysis present in the I4 paralytic cases. The majority, IO patients (71.4%), had spinal paralysis; the remaining four (28.6%) had bulbospinal paralysis. All cases were evaluated for clinical status 6o days after the onset of the disease (Table VII). Seven of the 15 patients (46.7%) were severely disabled, four (26.7%) had significant disability, and two 03.4%) had minor involvement. Only one patient with paralytic disease made a complete recovery. None of the 15 patients observed during this period had received live oral or inactivated poliovirus vaccine within four to 3o days before the onset of paralysis. Among those who had received either partial or complete immunization prior to the onset of illness, such immunizations had been given from six months to several years before the onset of the disease (Table IX). In two cases there had been close contact with a family member Vol. 52, No. 7, September 1976
82
P. J. IMPERATO
2
s: p:
s&
Co
s
cn
x
-i
-t
=1
m
n It
-3
CD
o1
.XI
CI 9
Ciit
C5
cc
to
ci
ci3 tt
cc
C
14
cc
C
n
ev
='
3
ct
C
=
e--
C-t -
&
_ ;T
c_.
md
o~ ~ ~ :r
~
> C)
C-
ic
O
CK;
CI
C CR
C
C
1-3
lct -1
-:
c4;
LI.
Iz
:r
..-
_..A
ci
_i
Q
0-
Erl m
In-
cn I-
_.01
I
-w
11J
;¢17
_.
6 -t
3
ON _.
cc
c-
ci
C-
CZ
bo
Co
cnoxcnt
eo o
-4
LM -
4
00
_''
w
o-
C;ic io UL Oz
I.
0
O~ ~-.
-C M
m-
W
v7
c
w
;
O-;-
Bull. N. Y. Acad. Med.
82 3
POLIOMYELITIS IN NEW YORK CITY
TABLE IX. IMMUNIZATION HISTORY OF CASES OF POLIOMYELITIS. NEW YORK CITY, 1961-1974 Cases (No.) 15
15
*Four
Complete* ?? complete Iniactivated polioviru.s vacc~ne (Salk) 4
5
None 6
Live oral poliovirus vaccine (Sabin) 0 3
12
or more doses of Salk vaccine; three or more doses of Sabin vaccine
who had received live oral poliovirus vaccine four to 6o days before the onset of illness. The first case (I967) was in a 3i-year-old white male whose son, aged seven months, had received a second dose of trivalent oral poliovirus vaccine 27 days before the onset of the father's illness. The second case (i968) was in a 3o-year-old black female whose four-month-old daughter had received a dose of trivalent oral poliovirus vaccine IO days before the mother's illness began. Both of these infections were with poliovirus Type II. IMMUNIZATION LEVELS
During July and August I972 the immunization program of the Bureau of Infectious Disease Control of the Department of Health undertook a random survey of households in 14 health districts of the city. Nine of these districts were considered poverty areas and five nonpoverty areas. Information was obtained on I,9I8 children less than ii years of age. Of these, I,748 (9I.o %) had received partial or complete immunization against poliomyelitis with inactivated or live oral poliovirus vaccine. However, the proportion of children who had received complete immunization (Table VIII) varied from a minimum of 4.7%0 in Jamaica East to a maximum of 77.8% in Sunset Park. In only four of the I4 districts surveyed-Fordham-Riverdale, Jamaica IVest, Richmond, and Sunset Park-were more than 6o% of children less than I I years of age fully immunized. Immunization levels among six-to-Io-year-old children were dramatically higher than those among one-to-five-year-old children for all districts. In large measure this is attributable to the fact that many children are immunized by the staff of the Department of Health's Bureau of School Health once they enter the school system. But even in the six-to-io-year age group there Vol. 52, No. 7, September 1976
824
P.
824
IMPERATO
J.
IMPERATO
POLIO I POLIO 11 _________. ___ POLIOIII * * * * *. -S S 0
100T
--I---.-
.,O..
--
0 0 0
80 0
0 0
0
a
0
O' 0
-
*
0
0
..'s
0
"
-O-
0
0 ,O-
"
0
O--
s-
O
O- -0
.,O- 0.
60+ z 0 w
a-
40+_
20 ±
n Iv vJ
, 1
2
3 AGE IN YEARS
4
5
6-7
Fig. 3. Percentage of each age group protected against polio I, polio 11, and polio III. 1,200 children tested in poverty areas of four boroughs of New York City Brooklyn, Bronx, Manhattan, and Queens in 1971.
such as Jamaica East, Bedford, and Central Harlem in which immunization levels remain extremely low, ranging from 8.oO to 38.1%. In 1972 the New York State Department of Health and the New York State Department of Education conducted a statewide survey for levels of immunity to diphtheria, poliomyelitis, measles, and rubella among children entering school.' In New York City questionnaires were certain poverty areas
i,251 schools, of which
responded. Of these, 270 were private schools and 265 were public. Information was collected on 49,408 entering students, of whom 66% were found to be fully
were sent to
535
Bull. N. Y. Acad. Med.
POLIOMYELITIS IN NEW YORK CITY
825
immunized against poliomyelitis. During this survey, the term "fully immunized" was employed to mean the receipt of three or more doses of either live or inactivated poliovirus vaccine. Of the I4,530 children entering private schools in New York City, 11,470 (79%0) had been fully immunized, whereas of the 34,878 children entering public schools only 20,881 (60%) had been fully immunized. In 1971 the sera of I,200 children from the poverty areas of four boroughs of New York City-Brooklyn, Bronx, Manhattan, and Queens-were tested by the New York City Department of Health for neutralization antibodies to poliovirus Types I, II, and III (see Figure 3). The sera also were being screened for levels of lead. Among children one year of age, protective antibodies were present against Type I poliovirus in 78%, against Type II in 88.5%, and against Type III in 74%. Among children three years of age, 92% had antibodies to Type I, 98% to Type II, and 8o% to Type III. Among children six to seven years of age, 92%0 demonstrated protective antibodies against Type I, 98.5% against Type II, and 88.5% against Type III. These data show much higher levels of protection in poverty areas than those surveys which recorded vaccination histories. Since wild poliovirus types are now rare in the United States, these children probably developed their protective antibodies in response to infection with vaccine virus acquired from vaccinated contacts. DIscussIoN Poliomyelitis was once a serious epidemic disease in New York City. Since the beginning of this century true major outbreaks occurred in the city in I9I6, I931, I935, I944, and I949.- In 1949, 2,446 cases and 179 deaths (73%) were recorded. Between these outbreaks large numbers of cases occurred. This long-standing pattern did not change until I955, when inactivated poliovirus (Salk) vaccine was first used widely in New York City. The vaccination of large numbers of persons led to a precipitous fall in the annual incidence of the disease. This downward trend was augmented by the introduction of live oral poliovirus (Sabin) vaccine in i96i. Use of the two vaccines resulted in the elimination of large pools of susceptible individuals. In spite of the widespread use of the poliovirus vaccines since i96i, sporadic cases of poliomyelitis have continued to occur. During the 14 years from i96i to 1974, when live oral poliovirus vaccine has been Vol. 52, No. 7, September 1976
8 2. 6 826
P.
J.
IMPERATO
used, 15 cases of poliomyelitis occurred. Of these, 73.4% occurred in children less than I5 years of age. This proportion of cases usually occurred in this age group when poliomyelitis was epidemic in the city. Since I970 only one case has occurred in New York City. An annual average of 2I.5 cases occurred in the United States since I970.3 Nationally, poliomyelitis is still on the decline, only I4 cases occurring in 1973-the lowest annual figure yet recorded.3 There is much variation in the death rate from poliomyelitis. In the United States in recent years the death rate has varied from a low of 6.o% in I970 to a high of 2 I.o% in 1973. Among the I cases which occurred in New York City since 196I, the death rate was 33.3%. For reasons which are not fully understood, males are more commonly affected by poliomyelitis than females.4 The male-to-female ratio in New York City since i96i has been i. i, somewhat less than the ratios observed in the prevaccination era. Differences in race-specific incidence rates for poliomyelitis are not consistent nationally.3 It is thought that these incidence rates are affected by other factors, since it has been noted that they vary so widely from one epidemic period to another and from one endemic period to another.3 Although whites accounted for 46.7% of all cases reported since i96I, they had the lowest incidence of any group (Table III). This is probably a reflection of the much higher immunization levels found among whites (Table VIII). Only two of the Is cases reported in this period occurred in the boroughs of Queens and Staten Island, which are composed largely of white, middle-class neighborhoods where immunization levels are high. The classic summer-fall peak has not been observed nationally since the early i960s. Rather, cases have occurred throughout the year.' In New York City cases in the early i960s occurred for the most part in the summer and fall. However, the last two reported cases (i968 and 1972) occurred during the winter. The etiologic poliovirus was Type I in 40% of the cases, Type III in another 40% of the cases, and Type II in 20% of the cases. Nationally, there has been great variability from year to year in these proportions. In 1973, 43% of the I4 cases reported were due to multiple poliovirus types. These cases represent infections caused by vaccine virus and are classified as vaccine-associated cases. Prior to 1971 multiple poliovirus types were not observed as causes of the disease.3 Bull. N. Y. Acad. Med.
POLIOMYELITIS IN NEW YORK CITY
827
Paralytic poliomyelitis has been observed to occur both in recipients of oral poliovirus vaccine and in their close contacts within 6o days of vaccination.5 Between i963 and 1970 approximately 147 million doses of trivalent oral poliovirus vaccine were distributed in the United States. During this period nine cases of vaccine-associated paralysis occurred in recipients and 2 I cases in contacts of recipients.5 The risk of the disease occurring in vaccine recipients is o.o6 per million doses of vaccine distributed, and among contacts of vaccine recipients it is 0.I4 per million doses distributed. In New York City two cases of poliomyelitis occurred among contacts of vaccine recipients. In the United States in I973 nine cases (64%) of poliomyelitis were vaccine-associated. Of these, four occurred among contacts of vaccine recipients. Cases among vaccine recipients continue to occur, however, among both adults and children, since both have contact with vaccine recipients. A number of cases of poliomyelitis have been found among vaccine recipients who after vaccination were recognized as having immunodeficiency disorders.3 Clinically, most of the patients with the disease in New York City since i96i (73.%) have been left seriously disabled. This pattern also has been observed nationally.3 Thus, once the diagnosis of paralytic poliomyelitis is made, the likelihood is great that the individual will be left with significant residual paralysis. Since I964 routine immunization of adults against poliomyelitis has been curtailed. The emphasis since that time has been on the routine immunization of infants. Every year an appraisal of the immunization status of the population is undertaken by the United States Public Health Service. This is assessed through a sample survey of the history of the types and number of doses of vaccine received.3 This form of survey is less satisfactory than a serologic survey. In 1973 the United States Immunization Survey revealed that only 60.4% of those in the one-to-four-year age group had received three or more doses of oral poliovirus vaccine.3 A survey of the same kind, conducted in New York City in 1972, revealed that in the one-to-five-year age group complete immunization varied from 1.3% in Jamaica East to 6z.7% in Staten Island (Table VIII). A survey of children entering school in 1972 in New York City revealed that 66% had received complete immunizations. Levels of immunization were found by history to be lowest in inner-city poverty areas among blacks and Puerto Ricans, the Vol. 52, No. 7, September 1976
828
P. P.
J. J.
IMPERATO
two groups who since i96i have had the highest race-specific incidence rate for the disease. However, in sharp contrast to this are the results of the serologic survey referred to earlier and illustrated in Figure 3. This survey, whose results are much more accurate than those of a survey of immunization history, indicates that high levels of immunity to all three poliovirus types exist among young children in New York City's innercity poverty areas. It is probable that slightly higher levels of immunity exist among young children in the middle-income areas of the city, where most children are routinely immunized. Crowding and poor levels of personal hygiene and environmental sanitation help to propagate vaccine virus from vaccine recipients in inner-city areas to their contacts. In view of the low percentage of young children in inner-city areas who have a history of receiving poliomyelitis vaccine, these demonstrated high levels of immunity mean that a significant proportion of these children acquire immunity through the ingestion of vaccine virus excreted by recipients of vaccine. It is possible also that a proportion of those interviewed gave poor histories, stating incorrectly that, children had not been immunized. In middle-income areas of the city, where levels of personal and environmental hygiene are higher, the transfer of vaccine virus from recipients to contacts probably occurs with much less frequency. The emphasis of current immunization programs in New York City is on the vaccination of infants and small children. The Department of Health, through its Bureau of Child Health, School Health, and Infectious Disease Control has made special efforts to raise levels of immunity throughout New York City by means of immunization programs conducted in health centers, child-health stations, pediatric treatment centers, and schools. Although these programs have reached fewer than the optimal number of children, levels of immunity to poliomyelitis in the city are quite high in young children, as demonstrated by the department's serologic survey in inner-city poverty areas. Estimations of group immunity to poliomyelitis, based on analysis of the numbers of doses of vaccine distributed in a given geographic area and on surveys for vaccination history, are often erroneous. The transfer of vaccine virus from vaccinated persons to their contacts can be efficient, especially in the poor hygienic environment of the inner city. It results in a high level of group immunity which is not reflected Bull. N. Y. Acad. Med.
POLIOMYELITIS IN NEW YORK CITY
82 9
in interview surveys. The results of such interview surveys therefore must be interpreted cautiously. To date, the dire predictions based upon such surveys have not materialized. This is additional evidence of the relatively high level of group immunity to poliomyelitis in the city. SUMMARY The epidemiology of poliomyelitis in New York City between i95i and 1974 has been described in detail. Since i96i paralytic poliomyelitis has been a rare, sporadic disease in New York City. The responsibility for the successful control of the disease is shared by both the private and the public health sectors. Immunization programs today aim at reaching the maximum number of infants and young children. Interview surveys conducted throughout the city have revealed extremely low levels of vaccination among young children in inner-city poverty areas, but serologic surveys in the same areas have demonstrated extremely high levels of immunity to all three poliovirus types. This disparity can be accounted for by incorrect responses to interviews and, more important, by the transfer of vaccine virus among children living in the crowded setting of the inner city, where levels of personal and environmental hygiene are poor. ACKNOWLEDGMENTS I wish to express my sincere thanks to Mr. Chih L. Hwa, Senior Statistician, Bureau of Health Statistics and Analysis, for his assistance in analyzing the data; to Mrs. Monique Daly for drawing the figures; and to Mr. Donald Biemiller, Project Coordinator, New York City Immunization Program, Center for Disease Control, U.S. Public Health Service, and his staff, for their efforts to control poliomyelitis in New York City. I also wish to thank Mrs. Earlene Price and Miss Debra Watson for typing the manuscript. REFERENCES mary 1973. Atlanta, Center for Disease 1. Immunization Levels In School EnterControl, 1975. ers, New York State, September, 197k 4. Top, F. H.: Communicable and InfecAlbany, N.Y., N.Y. State Dept. of tio71s Disease. St. Louis, Mosby, 1968. Health, 1973. 5. Immaonizatiot A4gainst Disease 19712. 2. Siegel, M., Greenberg, M., and Magee, M. C.: Poliomyelitis in New York City. Atlanta, Center for Disease Control, 1973. New York J. Med., 50:1119-23, 1950. 3. Poliomyelitis Surveillance, A nnual Sum-
Vol. 52, No. 7, September 1976
