WORLDWIDE EXPERIENCE WITH THE CR326F-DERIVED INACTIVATED HEPATITIS-A VIRUS-VACCINE IN PEDIATRIC AND ADULT-POPULATIONS - AN OVERVIEW

The worldwide experience to date with VAQTA(TM), a highly purified for malin-inactivated hepatitis A vaccine containing alum-adjuvant, is rev iewed. No serious adverse experience related to vaccination has been r eported. The vaccine has proven highly immunogenic, with seroconversio n detectable after a single dose in 90-99% of children 2-16 years old, and of adults under 77 kg (170 lb) body weight. There is a trend towa rd lower one-dose seroconversion rates with increasing age and with we ight > 77 kg. Early seroconversion in the latter groups may require tw o 25-unit doses given 2, 4 or 8 weeks apart, or a higher priming dose. Seroconversion induced by this vaccine has been shown to signify prot ection from clinical hepatitis A disease. The few vaccinees whose tite rs have waned to borderline levels responded anamnestically to a boost er, suggesting that the vaccine induces an immune memory response and should provide long-term protection.