Viral excretion and antibody titers in children infected with hepatitis A virus from an orphanage in western India.

BACKGROUND: Hepatitis A is endemic in India and mainly causes sporadic infections. However, children in childcare centers, schools and orphanages are vulnerable to common-source outbreaks as they have naive hosts. OBJECTIVES: To investigate hepatitis A outbreak in an orphanage from Pune, India. STUDY DESIGN: Monitoring of virus excretion and anti-HAV antibody levels in hepatitis A virus (HAV) infected children. RESULTS: The orphanage housed 93 children of the age 1 month-6.5 years. Analysis of the collected serum (n=78) and stool samples (n=63) revealed 20 children to be either positive for anti-HAV IgM antibodies or excreting HAV, 14 being symptomatic and 6 asymptomatic, while 32 were already anti-HAV IgG positive either due to past HAV exposure (n=7, mean log antibody titers: 2.96) or maternal antibodies (n=25, mean log antibody titers: 1.13). Serum samples, taken 4 weeks apart, did not show any significant difference in the IgM and IgG antibody levels either. However, virus excretion decreased significantly after 15 days in symptomatic children (mean log HAV RNA copies/ml 1.03+0.30), while asymptomatic children continued to excrete higher viral loads, at constant levels (mean log HAV RNA copies/ml 2.33+0.33), for up to 90 days. CONCLUSIONS: Though virus excretion continued up to 90 days in all HAV infected children, asymptomatic children excreted higher viral loads for longer period and hence can contribute significantly in person-to-person virus transmission. All children should be vaccinated in such set ups.