[The efficacy of the prevaccination detection of anti-HAV in hepatitis A vaccination programs]

The convenience of carrying out prevaccination detection studies of hepatitis A virus (HAV) markers depends on the relative costs of the detection and vaccination, as well as the prevalence of susceptible subjects in each population group to be vaccinated. The aim of this study was to analyze the efficacy of the systematic prevaccination detection of anti-HAV antibodies in Catalonia, Spain.

The following formula was applied: Unit cost of detection + (1-X) x Unit cost of vaccination of anti-HAV negative subjects = group vaccination cost, with X being the threshold of prevalence of marker under which detection no longer remains efficient. This prevalence was compared with the findings of a seroepidemiologic survey carried out in international travellers and food handlers.

The unit cost of the detection of anti-HAV was calculated as 2,733 pesetas, and the unit cost of the vaccination as 9,963 pesetas obtaining a prevalence anti-HAV threshold of 27%. This prevalence corresponds to travellers under the age of 30 years and food handlers under the age of 25 years.

The systematic detection of anti-HAV is only recommended in population groups in which prevalences higher than 27% may be expected. The vaccination is more efficient without a previous marker study under this threshold. According to this study, direct vaccination of food handlers under the age of 25 years (born after 1969) is recommended as is that of international travellers under the age of 30 years (born after 1964). In those over the age of these collectives, the prevaccination study is more efficient.