Estimating the number of HIV-infected gay sauna patrons in Taipei area

We make use of the voluntary HIV and syphilis test results conducted at five gay saunas in Taipei from August of 1999 to end of 2002 to estimate the number of HIV-positive gay saunas patrons in Taipei area by utilizing Hierarchical Bayes method in Generalized Removal Model for Open Populations (GERMO). Considering the effect of a nearby anonymous HIV quick test program on the gay sauna HIV serotesting data, we make use of the association between HIV and syphilis serotesting results from the gay sauna program to amend possible measurement error occurred at the time of data collection by utilizing the regression calibration method. The median estimates for the number of HIV-positive patrons of the five gay saunas increase from 120 (95% CI: 76.5-159.0) during the first half of 2000 to 224 (95% CI: 171.0-265.5) for the second half of 2002. The result, indicating two-fold increase within two and half years, confirms that the gay sauna patrons in Taipei area are at high risk for HIV infection.