Highly spontaneous seroconversion in e antigen positive South Asian children with chronic hepatitis B infection

doi:10.1016/j.jhep.2008.09.004 To the Editor: We read with interest the article by Fattovich et al. regarding the natural history of chronic hepatitis B (HBV) [1]. In their review discussing the natural history of HBV in children, they report the findings of studies in Asian children,with anoverall incidenceof less than10%spontaneous seroconversion by 10–15 years of age [1,2]. However the authors highlight that a higher rate of 75% spontaneous seroconversion was observed after a 13 year follow-up in Asian children living in Canada, possibly attributable to other factors such as their nutritional status [3]. We wish to report our experience of e antigen seroconversion in a diverse multi-ethnic cohort of children, including children of South Asian origin living in the United Kingdom with HBV, which is in keeping with the Canadian experience. Forty-one children (21 boys), with a median age of 4.3 years (range: 0.5–15.5) at diagnosis with untreated HBV, were followed up for a median duration of 81 months (range: 5–156). Thirty-six were perinatally infected. There were 20 children of South Asian origin (from the Indian sub-continent). The group also included 12 children of Far-Eastern or Southeast Asian origin, 5 Caucasian, 3 black and one child of mixed race. Of the 41 children, 6 (14.6%) spontaneously seroconverted to become e antibody positive after a median interval from referral of 32 months (range: 7–106). The natural seroconversion rates in children of South Asian origin was 5/20 (25%), all of whom were perinatally infected. None of the children of Far-Eastern or Southeast Asian origin seroconverted in keeping with the findings in previous studies. Our study is limited by small numbers and a relatively short duration of follow-up. Widely different seroconversion rates have been seen in Asian children. Whether environmental factors such as optimal nutrition in children living overseas have a favourable influence on seroconversion requires further investigation. To conclude, our findings, as in other studies illustrate the widely differing seroconversion rates even in populations of similar ethnicity, emphasising not only the importance of ethnic origin but also the natural seroconversion rates when considering antiviral treatment including the need for large population-based studies.