Drug-using MSM and transgendered Katoey in Thailand require culturally appropriate HIV and Hepatitis C targeted prevention

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Men who have sex with men (MSM) in Thailand, who often do so with transgendered men known as Katoey, do not perceive themselves to be engaging in sex between men, and are consequently requiring culturally appropriate targeted prevention, according to a study published in the the September 23rd issue of the journal, AIDS. The study also found that substance-using MSM are at high risk of both HIV and hepatitis C infection.

Little is known about the intersection of risk behaviours of MSM with substance use in Asia. Although it is increasingly recognised that they play a substantial role in the HIV epidemics of Thailand, Indonesia, India, China, Pakistan, Vietnam and other Asian countries, it is becoming apparent that traditional Western ideas of what constitutes sex between men do not often correlate with the Asian experience.

For example, in Thai culture there are three genders: male, female and Katoey: the latter are males who adopt female names, roles, and identities, and are perceived as a second category of women. Men who have sex with Katoey do not perceive themselves - and are not perceived by others in Thailand - to be engaging in sex between men.



The result of a statistical test which tells us whether the results of a study are likely to be due to chance and would not be confirmed if the study was repeated. All p-values are between 0 and 1; the most reliable studies have p-values very close to 0. A p-value of 0.001 means that there is a 1 in 1000 probability that the results are due to chance and do not reflect a real difference. A p-value of 0.05 means there is a 1 in 20 probability that the results are due to chance. When a p-value is 0.05 or below, the result is considered to be ‘statistically significant’. Confidence intervals give similar information to p-values but are easier to interpret. 

multivariate analysis

An extension of multivariable analysis that is used to model two or more outcomes at the same time.


Improvement in a tumour. Also, a mathematical model that allows us to measure the degree to which one of more factors influence an outcome.


In a bacteria culture test, a sample of urine, blood, sputum or another substance is taken from the patient. The cells are put in a specific environment in a laboratory to encourage cell growth and to allow the specific type of bacteria to be identified. Culture can be used to identify the TB bacteria, but is a more complex, slow and expensive method than others.


Something (such as a graft or device) implanted in a body tissue. In a context of prevention (such as contraception), the word refers to a device that will deliver an active agent slowly, over several months or years. This technique might be used one day to deliver antiretrovirals in the body for HIV prevention (PrEP) or treatment. 

Aware of the need for more research in this area, the US and Thai researchers sought to investigate MSM behaviours among populations of recovering substance users in Thailand. Their Opiate Users Research (OUR) cohort enrolled 2005 substance-using males over the age of 13 who presented for voluntary drug detoxification for opiate and/or methamphetamine use in northern Thailand.

Of the 2005 OUR cohort members, 1752 (84.7%) reported ever having had sex. Only 3.8% (66/1752) reported ever having sex with men. Of these, most (56/66; 84.8%) reported sex exclusively with Katoey; seven (10.6%) reported sex exclusively with another male-identified man; and three (4.5%) reported sex with both Katoey and with another male-identified man.

Although the MSM were significantly younger (median 25 vs. 30 years) than the heterosexual men, they had significantly higher numbers of lifetime sexual partners (median 20 vs. 6; p=0.0001); reported more female sex partners in the past year (median 2 vs. data not shown; p=0.002); were more likely to have had female paid sex partners (78.8% vs. 46.3%; p<0.0001) and were more likely to have been paid for sex (27.3 vs. 0.3%; p<0.0001) than the heterosexual men in the cohort.

The MSM were significantly more likely to have HIV infection on admission for drug detoxification than the heterosexual men in the cohort (31% vs. 16.2%; OR, 2.32; 95% CI, 1.36-3.96). Prevalence of hepatitis C infection was also greater amongst the MSM (65.2% vs. 41.9%; OR, 2.59; 95% CI, 1.55-4.34). However there was no difference seen in the prevalence of sexual transmitted infections.

Multivariate logistic regression analysis that compared MSM with all other sexually active male drug users found that younger age, Thai ethnicity, greater number of lifetime sex partners, having traded sex for money, and having a Fang Muk (a traditional Thai penile implant) were all independently associated with MSM behaviour. However, having been incarcerated, injection drug history, and being HIV-infected were found not to be independent predictors of MSM behaviour.

The authors concede that a limitation of their study is the absence of Katoey participants. Although the majority of MSM in their cohort reported sex with Katoey, "we do not have data on how many men (or women) self-identified as Katoey. Studies of HIV and other health concerns among Katoey are urgently needed to assess the prevention needs of these transgendered men."

The researchers point out that a Google search for Katoey resulted in more than 25,000 results detailing bars, clubs, dating services and chat rooms, whereas a Medline search "yielded no scientific publications. Although HIV and sexual health research may have overlooked Katoey, the sex and tourism industries have not," they remark.

They go on to argue that targeted prevention strategies "must take into account divergent cultural forms of identity, gender and behaviour", but were encouraged by the high knowledge of HIV infection and prevention reported by the MSM in their cohort.

In fact, MSM were more likely to have had an HIV test prior to engaging in drug detoxification (p<0.0001), more likely to agree with the statement that condoms were effective for HIV prevention (p<0.01), and do not often break or leak during sex (p<0.001) than the heterosexual men in the cohort.

However, they were also more likely to agree with the statement that condoms reduced sexual pleasure (p<0.0001) and that withdrawal before ejaculation can prevent HIV infection (p<0.001).

The researchers conclude that "the high rates of sexual and substance use risks [in Thai MSM] suggest that prevention remains a priority."


Beyrer C et al. High HIV, hepatitis C and sexual risks among drug-using men who have sex with men in northern Thailand. AIDS 19 (14): 1535-1540, 2005.