HIV transmission rates in Thailand: evidence of HIV prevention and transmission decline.
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.
Park
Lesley S
LS
Departments of Chronic Disease, Epidemiology and Microbial Diseases, Yale School of Public Health, New Haven, CT 06520-8034, USA. lesley.park@yale.edu
Siraprapasiri
Taweesap
T
Peerapatanapokin
Wiwat
W
Manne
Jennifer
J
Niccolai
Linda
L
Kunanusont
Chaiyos
C
D017280:Condoms / Q000706:statistics & numerical data; D005260:Female; D015658:HIV Infections / Q000453:epidemiology / Q000517:prevention & control* / Q000635:transmission*; D018451:Homosexuality, Male / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D011157:Population Dynamics; D011237:Predictive Value of Tests; D012307:Risk Factors; D012727:Sex Characteristics; D011477:Sex Work / Q000706:statistics & numerical data; D015819:Substance Abuse, Intravenous / Q000150:complications; D013785:Thailand / Q000453:epidemiology