Hepatitis A antibodies in Indonesian neonates and children

摘要

Objective: Five different epidemiologic patterns (very high, high, intermediate, low, and very low) become apparent when incidence rates and prevalence of age-specific antibodies to hepatitis A virus (HAV) (anti-HA) are examined. This study evaluated the age distribution of the prevalence of immunity to HAV in neonates and very young Indonesian children.Methods: The study population (n = 153) included neonates, from Indonesia, who were followed over 62 months. Sera were collected at birth and at months 1, 2, 12, 14, 24, 36, 48, 60, and 62. The HAV antibodies were determined by radioimmunoassay.Results: At birth almost all the children (96.8%) were anti-HA positive, having antibodies passively acquired from their mothers. They all became negative in the following 12 months. At the age of 1 year, 0.9% of the infants showed a positive serology for anti-HA. The percentage of children who acquired a natural immunization by HAV infections rose to 4.7% at the age of 2 years, 11.4% at 3 years, 20.3% at 4 years, and finally, 36.4% at 5 years of age.Discussion: Indonesia shows the pattern of a highly endemic area. More improvements in public health and sanitation can raise the age of infection in Indonesia. This epidemiologic shift may increase the probability of future epidemics of HAV in groups previously protected by immunity acquired in early childhood. This new epidemiologic pattern may have clinical and public health implications, because of the relatively large groups of older, unprotected individuals living in an environment that is still contaminated.