One in five adults in New York are putting themselves at risk of HIV by having sex with multiple partners or using needles to inject drugs, a study by the US Health Department stated.
Around 92 per cent of them do not think they are at risk, the study found.
The survey also found that out of the people with multiple sex partners, almost 60 per cent put themselves at risk by not always using condoms.
Compared to the national data, sexual risk-taking appears to be more common among New York City adults, but injection drug use appears to be roughly the same.
The findings highlight common misperceptions about HIV and underscore the importance of education and routine HIV testing.
"Far too many people are in danger of contracting HIV through risky behaviour," Dr Thomas R Frieden, Health Commissioner for New York City, said.
"Reducing the number of sex partners and protecting yourself and your partners by consistently using condoms will help you stay safe. We should all know our HIV status, regardless of whether we think we're at risk and health care providers should offer this test to their patients," he said.
The study, whose lead author is Trang Nguyen, is the first in a US to use a citywide survey of blood samples to estimate HIV prevalence.
The findings suggest that approximately 1.4 per cent of New York City adults are infected with HIV, about the same proportion that past studies have obtained by pooling case reports from hospitals, clinics and doctors' offices. (MORE)
The rate of those infected by HIV in New York City is nearly four times the national rate (0.37 per cent) and is a likely reflection of a larger population of ethnic minorities and men who have sex with men, the study found.
Keeping with past surveys, the new study found an especially large HIV burden among men who have sex with other men. Their infection rate was 14 per cent, approximately 38 times the citywide average.
Black and Hispanic New Yorkers have long been disproportionately affected by the HIV epidemic. Indeed, this survey showed that rates of HIV are nearly six times higher among black New Yorkers than white New Yorkers (3.3 versus 0.6 per cent), a trend that has been documented through other surveillance methods since the early 1980s.
The HIV rate among Hispanic New Yorkers (1.3 per cent) was more than twice that of whites. While HIV infection due to injection drug use has declined in New York City since the 1990s, the new study suggests the disease is still common among needle users, 21 per cent of whom have tested positive for HIV.
"If you are using drugs, get help to stop," added Frieden. "But protect yourself until you stop by not sharing equipment."
To reduce risky sexual behaviour, the Health Department is planning an educational campaign targeting men who have sex with men. The agency also distributes more than three million branded NYC condoms each month.
To reduce transmission among drug users, the US Health Department sponsors needle-exchange programmes in several boroughs, helps health care providers get their patients off drugs, and contracts with service organisations to provide treatment for addiction.
People who have HIV and Aids and who are on anti-retroviral treatment (ART) tend to take greater sexual risks than those who are positive but who are not on treatment.
That's according to a recent study by the Human Sciences Research Council (HSRC) into perceptions and behavioural risk relating to people who are HIV-positive.
The study's findings indicate that HIV-positive people on treatment tend to practise safe sex less frequently compared to those who are not on treatment.
They appear not to view the disease as a threat.
The study was conducted by Vuyiswa Mathambo, a research manager in the Child, Youth, Family and Social Development research programme.
The research was conducted by sampling a group of 104 HIV-positive men and women who had been receiving ART for more than six months and 111 HIV-positive men and women who were not receiving ART at the time of the study.
Most of those surveyed were women aged 26 to 30, unmarried, with a secondary level qualification and unemployed.
People in both groups were asked about their perceptions of the impact of HIV and Aids on the frequency with which they practised safe sex.
The report is published in the HSRC Review.
In terms of the statistics, more people who were in the treatment group viewed Aids as a disease that was no longer life-threatening and reported practising safe sex less often since starting treatment.
Of those interviewed, 84 percent of those in the treatment group said Aids was no longer a threat compared to 76 percent in the non-treatment group.
Sixty-three percent of those in the treatment group practised safe sex compared to 51 percent of those in the non-treatment group.
Mathambo writes that the study's findings showed a need to communicate appropriate HIV-prevention messages to those on treatment as it was still important to practise safe sex.
"ART is known to reduce viral loads, Aids-related illnesses and death and to improve the quality of life of those taking this treatment but concerns have been raised about the perceptions of risk as well as the behaviour of those receiving ART...
"While acknowledging the difficulty of linking risk perception and sexual practices, it was notable that some respondents had sought treatment for STIs (sexually transmitted infections) in both groups in the past two to three months," she says.
Mathambo adds that the study site was located within a hospital founded on a Catholic ethos, meaning that condoms may not have been as readily available.
Meanwhile, a comprehensive study by the Institute of Security Studies says that the politicisation of HIV and Aids has impacted on corruption and accountability.
The study, A Lethal Cocktail by Collette Schulz-Herzenberg, explores the impact of corruption on HIV and Aids prevention and treatment efforts in South Africa.
"It (politicisation) appears to relate indirectly to instances of abuse and corruption on the part of public officials and other individuals by affording a degree of protection."
