Two-dose hepatitis A vaccine effective in Thai children.

2004 FEB 11 - (NewsRx.com & NewsRx.net) -- A two-dose hepatitis A vaccine regimen is effective in Thai children.

"As fewer children in Thailand are exposed to hepatitis A virus (HAV) and so do not have seroprotective anti-HAV antibodies, they are becoming an important source of HAV transmission. A flexible HAV vaccination schedule would facilitate incorporation of the vaccine into existing immunization programs, and we compared the immunogenicity and safety of three HAV immunization schedules. An open, randomized, clinical trial was carried out in which healthy children were given a primary dose of the inactivated hepatitis A vaccine, Avaxim 80 pediatric, with a booster dose 6, 12, or 18 months later," scientists in Thailand report.

"Anti-HAV geometric mean concentrations (GMC), seroconversion rates, and GMC ratios (GMCR) of the three schedules were compared and reactogenicity was evaluated," said Somsak Lolekha and colleagues at Mahidol University. "Seroconversion rates were above 98% (per group) up to the booster. The three schedules were equivalent in terms of GMCRs, each eliciting a large booster effect. Local reactions were reported for fewer than 9% of each group after dose one and less frequently after the booster dose. Injection site pain, gastrointestinal tract disorders, and fever were the ...