Background: Analysis of HIV transmission rates has provided insight into the impacts of HIV-related prevention programming and policies in the United States by providing timely information beyond incidence or prevalence alone. The purpose of this analysis is to use transmission rates to assess past prevention efforts and explore trends of the epidemic in subpopulations within Thailand.
Methods: Asian Epidemic Model HIV incidence and prevalence were used to calculate transmission rates over time nationally and among high-risk populations.
Results: A national HIV/AIDS program implemented in Thailand in the 1990s that targeted sex workers and the general population was correlated with a decrease in new cases despite high prevalence. The turning point of the epidemic was in 1991 when the national transmission rate was 32%. By the late 1990s, the rate dropped to less than 4%. All subpopulations experienced a rate decline; however, sex workers still experienced higher transmission rates.
Conclusions: The declining trend in HIV transmission rates despite ever-growing prevalence indicates prevention success correlated with the national HIV/AIDS program. Data from subgroup analyses provide stronger evidence of prevention success than incidence alone, as this measure demonstrates the effect of efforts and accounts for the burden of disease in the population.