Particularly in southern Vietnam, only seven percent of men surveyed while attending clinics for sexually transmitted infections had used condoms.
Cambodia and Thailand are the only two Asian countries where HIV/AIDS cases are declining, largely because of widespread condom usage -- more than 90 percent -- in their commercial sex establishments.
Prostitution is also no longer the driving force of AIDS/HIV infections in these countries, the WHO says.
Only 16 percent of HIV/AIDS cases in Thailand and 21 percent cases in Cambodia developed from the sex industry compared with 80 to 90 percent previously during the peak of the epidemic in the last decade.
At one time, about half the number of sex workers in Thailand's northern Chiang Mai city and Cambodia's Sihanoukville city were ill with HIV/AIDS.
Most new infections are contracted through marital and casual sex, where condom use is low.
RSS