[Prevalence of anti-HAV antibodies and efficacy of pre-vaccine detection at institutions for mentally retarded of the city of Alicante].

OBJECTIVE

The aim of this study was to investigate the prevalence and efficacy of the anti-HAV antibodies detection in institucions for mentally retarded people in the city of Alicante.

DESIGN

Prevalence study.

SETTING

Two institucions for mentally retarded people in the city of Alicante.

PARTICIPANTS

One hundred and seven residents and seventy seven in care of them.

MEASUREMENTS AND MAIN RESULTS

We have investigated the anti-HAV antibodies prevalence by enzymeinmunoanalysis of microparticle test. The efficacy of the anti-HAV antibodies detection before the vaccination has been studied by calculating the threshold of prevalence with the following formula: unit cost of detection + (1 - X) x unit cost vaccination anti-HAV negative subjects = unit cost vaccination.

RESULTS

The global prevalence of anti-HAV antibodies was 56.5% (95% CI, 49-63.7). The prevalence of the residents was 55.1% (95% CI, 45.2-64.7) and 58.4% in care of them (95% CI, 46.6-69.5). Among the sociodemographic variables evaluated only the age was associated with the prevalence of anti-HAV antibodies (p < 0.001). The unit cost of prevaccination detection of anti-HAV antibodies was calculated as 998 pesetas and the unit cost of the vaccination as 3595, obtaining a prevalence anti-HAV threshold of 27.8%.

CONCLUSIONS

The prevalence of anti-HAV antibodies in this collective studied is similar to the prevalence of anti-HAV antibodies of the spaniard population. The direct vaccination without a previous marker study is recommended to people under the age of 31 in this population group.