Correspondence
Another concern is the rate (only 30%) of people positive for hepatitis B surface antibody (anti-HBs) in this large population. Authors used ELISA kits manufactured in China to measure hepatitis B serological markers. The performance of the ELISA kits for HBsAg made in China is nearly equal to that of the highly sensitive reagents such as the Abbott kit;2 however, the ELISA kits for anti-HBs made in China have lower sensitivity than the Abbott kit. In an investigation of the positive rate of anti-HBs in 1016 serum samples, 73% of samples were positive for antiHBs (≥10 mIU/mL) with the Abbott kit test, whereas only 63% were positive in the China-made test;3 nearly half of the samples with anti-HBs concentrations between 10–50 mIU/mL were negative in the China-made test.3 In vaccinees or people with self-resolved infection, anti-HBs concentrations between 2–9·9 mIU/mL were also considered to represent immunity to hepatitis B virus;4 however, more than 95% of such samples were negative for anti-HBs in the China-made test.3 Therefore, the positive rate (30%) of anti-HBs in Liu and colleagues Article1 is probably an underestimate, leading to overestimation of the proportion (63%) of the Chinese rural men susceptible to hepatitis B virus infection. I declare no competing interests.
Yi-Hua Zhou [email protected] Departments of Infectious Diseases and Laboratory Medicine, Nanjing Drum Tower Hospital, Nanjing University Medical School, Nanjing 210008, China; and Jiangsu Key Laboratory for Molecular Medicine, Nanjing University Medical School, Nanjing, China 1
2
3
Liu J, Zhang S, Wang Q, et al. Seroepidemiology of hepatitis B virus infection in 2 million men aged 21-49 years in rural China: a populationbased, cross-sectional study. Lancet Infect Dis 2015; 16: 80–86. Zhang S, Li RT, Wang Y, Liu Q, Zhou YH, Hu Y. Seroprevalence of hepatitis B surface antigen among pregnant women in Jiangsu, China, 17 years after introduction of hepatitis B vaccine. Int J Gynaecol Obstet 2010; 109: 194–97. Feng Z, Bi Y, Zhang S, Chen J, Hu Y, Zhou YH. Evaluation of domestic qualitative reagents for detecting anti-HBs in assessing the immunity to hepatitis B virus. Chinese J Health Lab Technol 2013; 23: 1493–95.
www.thelancet.com/infection Vol 16 February 2016
4
McMahon BJ, Dentinger CM, Bruden D, et al. Antibody levels and protection after hepatitis B vaccine: results of a 22-year follow-up study and response to a booster dose. J Infect Dis 2009; 200: 1390–96.
Authors’ reply We appreciate Jördis Ott and colleagues’ and Yi-Hua Zhou’s comments on our Article1 about hepatitis B virus in 2 million men in rural China. As mentioned in our Article, data for hepatitis B virus infection in men of a reproductive age in rural China is scarce and the last report about this was in 2006.2,3 Our data was from the National Free Preconception Health Examination Project (NFPHEP) launched by the Chinese National Health and Family Planning Commission. The NFPHEP provides an opportunity to provide counselling for individuals with hepatitis B virus about how to prevent disease transmission and progression and identify and vaccinate susceptible contacts.4 Our results showed that hepatitis B surface antigen (HBsAg) prevalence in rural men aged 21–49 years was 5·5–6·5%, which was lower than the prevalence in the 21–49 year old group (7·7–12·0%) in the 2006 national survey.2,3 Participants in our study were in the 15–44 year old group in 2006 by birth cohort. HBsAg prevalence in our study was also lower than the prevalence in the 15–44 year old group (6·4–12·0%) reported by Xiaofeng Liang and colleagues in the 2006 national survey.2,3 Hence our interpretation about the changing hepatitis B virus endemic in men in rural China is reasonable. As for the discrepancy (eg, reversed association of HBsAg with education) with the results reported by Liang and colleagues, we have explained this in the Discussion section in our Article. Ott and colleagues raise concerns about the minor difference in HBsAg prevalence between vaccinated and non-vaccinated participants. The imple mentation of the universal hepatitis B vaccination programme for infants was started in 1992 in China; however, the participants in our study
were born from 1961 to 1991, and did not benefit from the universal hepatitis B vaccination policy for infants. They were vaccinated voluntarily at their own cost, yet their history of hepatitis B vaccination was not recorded. Hence, vaccination history was selfreported by the participants based on their memory in our study. Recall bias seemed unavoidable to some extent. We have mentioned this point in the limitation part of our Discussion. Zhou questioned the sensitivity of ELISA kits manufactured in China. All the reagent kits selected by 220 counties in our study were tested by the National Center of Clinical Laboratories for Quality Inspection and Detection with reagents produced by Abbott, USA, as the reference standard. Sensitivity, specificity, and kappa values of the selected reagents were above 95%. As for quality control, an external quality assessment process was done twice a year. The accuracy rates of detection were 97·4% for HBsAg, 98·6% for hepatitis B surface antibody, 98·3% for hepatitis B e antigen, 97·6% for antihepatitis B e antibody, and 94·5% for anti-hepatitis B core antibody. The test sensitivity is similar to that of previous studies,2,3 which also used ELISA kits manufactured in China. We declare no competing interests.
*Min Liu, Shikun Zhang, Jue Liu, Qiaomei Wang, Haiping Shen [email protected] Department of Epidemiology and Biostatistics, School of Public Health, Peking University, Beijing, China (ML, JL); and Department of Maternal and Child Health, National Health and Family Planning Commission of the PRC, Beijing, China (SZ, QW, HS) 1
2
3
Liu J, Zhang S, Wang Q, et al. Seroepidemiology of hepatitis B virus infection in 2 million men aged 21–49 years in rural China: a populationbased, cross sectional study. Lancet Infect Dis 2015; 16: 80–86. Liang X, Bi S, Yang W, et al. Epidemiological serosurvey of hepatitis B in China-declining HBV prevalence due to hepatitis B vaccination. Vaccine 2009; 27: 6550–57. The Ministry Of Health Disease Control Bureau, Chinese Center for Disease Control and Prevention. The report of a national sero-epidemiological survey of hepatitis B virus infection in the whole population in China, 2006. Beijing: People’s Medical Publishing House, 2011.
151
Correspondence
4
Vellozzi C, Averhoff F. An opportunity for further control of hepatitis B in China? Lancet Infect Dis 2015; 16: 10–11.
Respiratory co-morbidities in people with HIV We thank James Brown and colleagues1 for their comments on our study,2 and for recognising both the contribution of this work and the care we took in expressing its limitation. We agree entirely with Brown and colleagues that including projections for additional important non-communicable diseases, including neurocognitive disorders and respiratory diseases, could provide a fuller picture of the future disease burden in ageing
152
HIV-positive individuals. Our intention with this detailed modelling work was to provide an overview of some of the major important non-communicable diseases, providing insight into how their prevalence will change as the Dutch HIV-positive population ages. We limited this study to the important non-communicable diseases for which there were high quality data available in both young and older HIVpositive individuals so that we could be confident about the predictions made. Fortunately, studies such as the AGEhIV cohort study3 are increasingly investigating a larger scope of noncommunicable diseases in both older HIV-positive and older HIV-negative individuals. Our hope is that future work can build on these predictions using the increasing availability of
data to provide a fuller picture of noncommunicable diseases in ageing HIVpositive individuals. We declare no competing interests.
*Mikaela Smit, Timothy Hallett [email protected] Department of Infectious Disease Epidemiology, Faculty of Medicine, Imperial College London, London, UK 1
2
3
Brown J, Smith C, Johnson M, Lipman M, Abubakar I. Respiratory co-morbidities in people with HIV. Lancet Infect Dis 2015; 16: 21. Smit M, Brinkman K, Geerlings S, et al. Future challenges for clinical care of an ageing population infected with HIV: a modelling study. Lancet Infect Dis 2015; 15: 810–18. Schouten J, Wit FW, Stolte IG, et al. Cross-sectional comparison of the prevalence of age-associated comorbidities and their risk factors between HIV-infected and uninfected individuals: the AGEhIV cohort study. Clin Infect Dis 2014; 59: 1787–97.
www.thelancet.com/infection Vol 16 February 2016
Another concern is the rate (only 30%) of people positive for hepatitis B surface antibody (anti-HBs) in this large population. Authors used ELISA kits manufactured in China to measure hepatitis B serological markers. The performance of the ELISA kits for HBsAg made in China is nearly equal to that of the highly sensitive reagents such as the Abbott kit;2 however, the ELISA kits for anti-HBs made in China have lower sensitivity than the Abbott kit. In an investigation of the positive rate of anti-HBs in 1016 serum samples, 73% of samples were positive for antiHBs (≥10 mIU/mL) with the Abbott kit test, whereas only 63% were positive in the China-made test;3 nearly half of the samples with anti-HBs concentrations between 10–50 mIU/mL were negative in the China-made test.3 In vaccinees or people with self-resolved infection, anti-HBs concentrations between 2–9·9 mIU/mL were also considered to represent immunity to hepatitis B virus;4 however, more than 95% of such samples were negative for anti-HBs in the China-made test.3 Therefore, the positive rate (30%) of anti-HBs in Liu and colleagues Article1 is probably an underestimate, leading to overestimation of the proportion (63%) of the Chinese rural men susceptible to hepatitis B virus infection. I declare no competing interests.
Yi-Hua Zhou [email protected] Departments of Infectious Diseases and Laboratory Medicine, Nanjing Drum Tower Hospital, Nanjing University Medical School, Nanjing 210008, China; and Jiangsu Key Laboratory for Molecular Medicine, Nanjing University Medical School, Nanjing, China 1
2
3
Liu J, Zhang S, Wang Q, et al. Seroepidemiology of hepatitis B virus infection in 2 million men aged 21-49 years in rural China: a populationbased, cross-sectional study. Lancet Infect Dis 2015; 16: 80–86. Zhang S, Li RT, Wang Y, Liu Q, Zhou YH, Hu Y. Seroprevalence of hepatitis B surface antigen among pregnant women in Jiangsu, China, 17 years after introduction of hepatitis B vaccine. Int J Gynaecol Obstet 2010; 109: 194–97. Feng Z, Bi Y, Zhang S, Chen J, Hu Y, Zhou YH. Evaluation of domestic qualitative reagents for detecting anti-HBs in assessing the immunity to hepatitis B virus. Chinese J Health Lab Technol 2013; 23: 1493–95.
www.thelancet.com/infection Vol 16 February 2016
4
McMahon BJ, Dentinger CM, Bruden D, et al. Antibody levels and protection after hepatitis B vaccine: results of a 22-year follow-up study and response to a booster dose. J Infect Dis 2009; 200: 1390–96.
Authors’ reply We appreciate Jördis Ott and colleagues’ and Yi-Hua Zhou’s comments on our Article1 about hepatitis B virus in 2 million men in rural China. As mentioned in our Article, data for hepatitis B virus infection in men of a reproductive age in rural China is scarce and the last report about this was in 2006.2,3 Our data was from the National Free Preconception Health Examination Project (NFPHEP) launched by the Chinese National Health and Family Planning Commission. The NFPHEP provides an opportunity to provide counselling for individuals with hepatitis B virus about how to prevent disease transmission and progression and identify and vaccinate susceptible contacts.4 Our results showed that hepatitis B surface antigen (HBsAg) prevalence in rural men aged 21–49 years was 5·5–6·5%, which was lower than the prevalence in the 21–49 year old group (7·7–12·0%) in the 2006 national survey.2,3 Participants in our study were in the 15–44 year old group in 2006 by birth cohort. HBsAg prevalence in our study was also lower than the prevalence in the 15–44 year old group (6·4–12·0%) reported by Xiaofeng Liang and colleagues in the 2006 national survey.2,3 Hence our interpretation about the changing hepatitis B virus endemic in men in rural China is reasonable. As for the discrepancy (eg, reversed association of HBsAg with education) with the results reported by Liang and colleagues, we have explained this in the Discussion section in our Article. Ott and colleagues raise concerns about the minor difference in HBsAg prevalence between vaccinated and non-vaccinated participants. The imple mentation of the universal hepatitis B vaccination programme for infants was started in 1992 in China; however, the participants in our study
were born from 1961 to 1991, and did not benefit from the universal hepatitis B vaccination policy for infants. They were vaccinated voluntarily at their own cost, yet their history of hepatitis B vaccination was not recorded. Hence, vaccination history was selfreported by the participants based on their memory in our study. Recall bias seemed unavoidable to some extent. We have mentioned this point in the limitation part of our Discussion. Zhou questioned the sensitivity of ELISA kits manufactured in China. All the reagent kits selected by 220 counties in our study were tested by the National Center of Clinical Laboratories for Quality Inspection and Detection with reagents produced by Abbott, USA, as the reference standard. Sensitivity, specificity, and kappa values of the selected reagents were above 95%. As for quality control, an external quality assessment process was done twice a year. The accuracy rates of detection were 97·4% for HBsAg, 98·6% for hepatitis B surface antibody, 98·3% for hepatitis B e antigen, 97·6% for antihepatitis B e antibody, and 94·5% for anti-hepatitis B core antibody. The test sensitivity is similar to that of previous studies,2,3 which also used ELISA kits manufactured in China. We declare no competing interests.
*Min Liu, Shikun Zhang, Jue Liu, Qiaomei Wang, Haiping Shen [email protected] Department of Epidemiology and Biostatistics, School of Public Health, Peking University, Beijing, China (ML, JL); and Department of Maternal and Child Health, National Health and Family Planning Commission of the PRC, Beijing, China (SZ, QW, HS) 1
2
3
Liu J, Zhang S, Wang Q, et al. Seroepidemiology of hepatitis B virus infection in 2 million men aged 21–49 years in rural China: a populationbased, cross sectional study. Lancet Infect Dis 2015; 16: 80–86. Liang X, Bi S, Yang W, et al. Epidemiological serosurvey of hepatitis B in China-declining HBV prevalence due to hepatitis B vaccination. Vaccine 2009; 27: 6550–57. The Ministry Of Health Disease Control Bureau, Chinese Center for Disease Control and Prevention. The report of a national sero-epidemiological survey of hepatitis B virus infection in the whole population in China, 2006. Beijing: People’s Medical Publishing House, 2011.
151
Correspondence
4
Vellozzi C, Averhoff F. An opportunity for further control of hepatitis B in China? Lancet Infect Dis 2015; 16: 10–11.
Respiratory co-morbidities in people with HIV We thank James Brown and colleagues1 for their comments on our study,2 and for recognising both the contribution of this work and the care we took in expressing its limitation. We agree entirely with Brown and colleagues that including projections for additional important non-communicable diseases, including neurocognitive disorders and respiratory diseases, could provide a fuller picture of the future disease burden in ageing
152
HIV-positive individuals. Our intention with this detailed modelling work was to provide an overview of some of the major important non-communicable diseases, providing insight into how their prevalence will change as the Dutch HIV-positive population ages. We limited this study to the important non-communicable diseases for which there were high quality data available in both young and older HIVpositive individuals so that we could be confident about the predictions made. Fortunately, studies such as the AGEhIV cohort study3 are increasingly investigating a larger scope of noncommunicable diseases in both older HIV-positive and older HIV-negative individuals. Our hope is that future work can build on these predictions using the increasing availability of
data to provide a fuller picture of noncommunicable diseases in ageing HIVpositive individuals. We declare no competing interests.
*Mikaela Smit, Timothy Hallett [email protected] Department of Infectious Disease Epidemiology, Faculty of Medicine, Imperial College London, London, UK 1
2
3
Brown J, Smith C, Johnson M, Lipman M, Abubakar I. Respiratory co-morbidities in people with HIV. Lancet Infect Dis 2015; 16: 21. Smit M, Brinkman K, Geerlings S, et al. Future challenges for clinical care of an ageing population infected with HIV: a modelling study. Lancet Infect Dis 2015; 15: 810–18. Schouten J, Wit FW, Stolte IG, et al. Cross-sectional comparison of the prevalence of age-associated comorbidities and their risk factors between HIV-infected and uninfected individuals: the AGEhIV cohort study. Clin Infect Dis 2014; 59: 1787–97.
www.thelancet.com/infection Vol 16 February 2016
