MSM are known traditionally as a high-risk group in terms of carrying and spreading the virus in Taiwan.IDUs have become more susceptible to the transmission of HIV recently. They may also pass on the disease to their sexual partners, effectively starting a domino effect.

33.2% of the reported HIV cases in Taiwan are from the MSM population. A study by Cheng et al. in Taiwan showed that the highest HIV prevalence rate (5-10%) was found in MSM. The HIV prevalence rates among MSM at gay saunas in Taiwan in the years 2000, 2001, 2002, 2003 and 2004 were 9.5% (33/348), 5.2% (16/307), 6.9% (38/549), 6.9% (38/549) and 7.6% (33/434) respectively. MSM represent the main risk group for HIV infection in Taiwan. The largest concern was that some studies show that only 36% of them use condoms.

From our experience, homosexual behavior is highly stigmatized in Taiwan, and many MSM do not openly declare themselves as MSM. As a result, preventive education and awareness-raising measures specifically targeted at MSM have not been implemented effectively until recently.

In Taiwan, the first case of HIV infection contracted through IDU was identified in 1988. Since then, screening prison inmates with drug habits has become mandatory. According to our surveillance data, HIV prevalence in IDUs had remained below 0.1% till the end of 2003.?In 2004 however,the average HIV prevalence rate of IDUs was up to 2%. Meanwhile,we have also found the most common way of heroine ingestion in Taiwan is through injection rather than inhalation. IDUs are thus becoming a significant part of the HIV infected population, because of their tendency to share needles and other equipment with fellow addicts.

Unlike Australia, Canada, or the U.S., needles in Taiwan are not strictly regulated. However, since the police often go to drugstores to seek clues of drug offenses, fewer and fewer drug users dare to buy needles openly. As a result, it was likely that drug users would resort to needle sharing as the only alternative. Illegal drug usage is also strictly prohibited by law and socially unacceptable in Taiwan.?For this particular population group, there is an obvious lack of information on prevention against HIV.?The absence of appropriate detoxification and intervention services has also limited the access of IDUs to proper testing, care, and treatment.

IDU contributes to the HIV epidemic's spread far beyond the circle of those who actually do the injection. People who have sex with IDUs are also at great risk of contracting HIV. Children born to mothers who have already contracted HIV through sharing needles or having sex with IDUs may become infected as well. TThe Word Health Organization (WHO) has warned that the number of AIDS cases would grow explosively as soon as the HIV makes it away into the IDU population. AIDS crisis situation calls for immediate action responding to this rapid increase in spread of HIV and AIDS, Taiwan’s Centers for Disease Control (CDC) secured the Executive Yuan’s budget of NT$80 million (US$2.4 million) and its full support to implement a harm reduction strategy, patterned on successful programs in use oversea.

Young people, who are becoming increasingly sexually active, are contracting the virus in increasing numbers. HIV-positive persons in their 20s and 30s account for 38% and 34% respectively of the total number. Taiwan's younger generations have become more and more open-minded about sex; most sexual intercourse between youngsters occur without proper protection. According to data from the National Taiwan Normal University, only 30% of college students use condoms each time they have sex. The lack of awareness may trigger a disastrous outbreak among young adults.

One-night stands have become increasingly popular among youths, many of whom meet through the Internet. Studies by the Department of Health show that 10 to 15% of male teens have had premarital sex, up from just 4% ten years ago. In the same period, premarital sex among female teens rose from 2% to 7%.

In terms of gender,the disease has predominantly affected males. In 2003, the male-to-female ratio was 21:1, and men accounted for 95% of all HIV-positive cases. However, there has been a steady increase in female cases over recent years, and the male-to-female ratio reduced to 9:1 in 2006
Although female cases only add up to 7.4% of the total number of HIV infection in Taiwan, most women contracted HIV through sexual acts with their male partners. One of the issues of great concern to Taiwan CDC is the significant increase over the past decade in married women among HIV patients. Moreover, woman's physiological features make them more vulnerable to the virus than men. ? In recent years, Taiwanese businessmen have been traveling frequently to various parts of Mainland China to pursue new entrepreneurial opportunities, at the same time exposing themselves to and being infected with HIV through prostitutes and escorts. One of the many consequences is that wives of those traveling Taiwanese businessmen unknowingly become vulnerable to and victims of the spread of HIV.

Sex workers are also a vulnerable population at high risk of HIV infection. Prostitution has been prohibited in Taiwan since the enforcement of the Law of Maintaining Public Order in 1990.However, the sex industry never disappeared and simply went underground. A recent survey of 39 sex workers still operating shows that 86% of them do not persuade clients to use condoms.In this business, it appears that the use of condoms has not become a general practice and thus the risk of HIV infection is extremely high.The problem is that both sex workers and the clients believe that luck is on their side. Unsafe drug-injecting practices often come hand-in-hand with commercial sex in furthering HIV spread.Moreover, many women have entered Taiwan recently from neighboring Asian countries to illegally work in the local underground sex industry. These foreign females are particularly vulnerable to the infection because they usually have a language barrier and they have no valid visas, which discourages them from seeking appropriate medical care.