Immunogenicity and side-effects of the inactivated hepatitis A vaccine in periodic fever, aphthous stomatitis, pharyngitis, and adenitis patients.

The aim of this study was to compare the immunogenicity and side-effects of hepatitis A virus (HAV) vaccination between periodic fever, aphthous stomatitis, pharyngitis, and adenitis (PFAPA) patients and healthy controls who have not been previously exposed to HAV. A prospective observational study was carried out of 28 PFAPA patients and 76 controls who received two doses of the vaccine. Immunogenicity was expressed as seroconversion and seroprotection rates; mean HAV-immunoglobulin G concentration was measured at 0, 1, 7 and 18 months. Side-effects were defined as incidence of adverse events and the effect of vaccination on PFAPA symptoms. All participants were seronegative and seroconverted at 1 month. One month after primary vaccination, 92.9% of PFAPA patients and 77.6% of the controls attained seroprotection, while the rates increased to 100% and 96.1%, respectively, 1 month after the second dose. Seroprotection rates remained adequate 1 year after completion of vaccination. In conclusion, two doses of the inactivated HAV vaccine are well-tolerated and effective in children with PFAPA.