A clinical trial was conducted on 44 healthy young volunteers in order to assess the immunogenicity and safety of an inactivated hepatitis A vaccine. The preparation was injected intramuscularly in the deltoid region at month 0, 1, 6 and the serological follow-up was carried out at month 1, 2, 6, 7, 12. Each sample was tested for total anti-HAV with a new experimental kit manufactured by Boehringer Mannheim (B.M.) (Germany). Results were expressed as mIU/ml. Side effects after vaccine administration were relatively unfrequent and resulted to be mild, the most frequent being local pain at the site of injection. Seroconversion rates were 97.6% at month 1 and 100% at month 2. At all the following times (month 6, 7, 12) the presence of antibodies was maintained in all subjects. Anti-HAV Geometric Mean Titres resulted to be 379, 402, 486, 3917 and 1489 mIU/ml at month 1, 2, 6, 7 and 12 respectively. Two different kinetics of antibody response were noted at month 1 and 2. Most vaccinees increased their antibody titre after the second dose; some of them, however, showed a decrease of antibody titre after the second dose when compared to that achieved after the first one. Preliminary tests seem to explain such a behaviour with a decrease of IgM antibodies not yet compensated by an increase of IgG. The results of our study show how the inactivated hepatitis A vaccine is safe and highly immunogenic. Its use can be useful in subjects at risk of infections transmitted by the fecal-oral route, such as travellers from developed to developing countries.
|Title of host publication||Journal of Preventive Medicine and Hygiene|
|Number of pages||5|
|Publication status||Published - 1993|
ASJC Scopus subject areas
- Public Health, Environmental and Occupational Health