U of T study finds rate of increase in HIV diagnoses highest among heterosexuals
In HIV research, they’re called “low-risk heterosexuals,” yet this group experienced the most dramatic increase in HIV diagnoses – 114 per cent – in Ontario between 2000 and 2004 (overall, HIV diagnoses increased by 39 per cent in the same period).
The information was released in the eighth annual Ontario HIV/AIDS Surveillance Report, conducted by Dr. Robert Remis, a professor in U of T’s Department of Public Health Sciences. “The situation is of great concern,” says Remis. “The epidemic is growing in almost every category.”
Remis says further study is required to understand why HIV prevalence is increasing in the heterosexual population by 13 per cent a year. He surmises that people could have been infected by current or previous injection drug users, by people from endemic regions (sub-Saharan Africa and the Caribbean) now living in Canada, or by people they met while travelling to endemic or emerging endemic regions. “The list of endemic countries needs to be modified,” says Remis. “There are epidemics brewing in eastern Europe, parts of south Asia and pockets of Latin America and Central America.”
According to Remis’s statistical model, an estimated 24,250 Ontarians are living with HIV (as of 2004) but only 66 per cent of them know they are infected. The statistical model is based in part on data collected from newly diagnosed cases, surveillance systems for HIV and AIDS already in place and research studies of people tested more than once for HIV.
In terms of overall numbers, the most affected remain men who have sex with men. While the majority of gay men practise safe sex, Remis says new infections are occurring within the 15 to 20 per cent who engage in risky behaviour. He blames safe-sex fatigue, treatment optimism, and the drug crystal meth and other kinds of substance abuse. “Since highly active antiretroviral therapy became available in 1996, there’s less fear about the nasty consequences of HIV infection,” says Remis. But the honeymoon with this new therapy could be over. “These drugs have been so recent, we don’t really know the long-term prognosis,” he says. “They improve life expectancy and the quality of life in the short term, but there are issues of emerging resistance and such side effects as strokes, diabetes and high cholesterol.”
The good news is that statistical modelling can drive effective public policy. When researchers discovered that pregnant mothers taking highly active antiretroviral therapy could lower HIV transmission to their offspring to about one per cent, Remis conducted a study that showed that fewer than 40 per cent of pregnant women in Ontario were being tested for HIV. A new policy offering universal testing pushed that number to 90 per cent in 2004. “It’s one of the most successful prenatal programs in North America,” says Remis. Other studies led to the creation of the African and Caribbean Council on HIV/AIDS in Ontario. “As a result of putting numbers around this epidemic, we can say it’s important,” says Remis. “We started to mobilize provincial and federal governments to act.”
But to stabilize the epidemic, Remis says governments have to invest still more in primary prevention – in safe-sex education campaigns and increased testing. He also advocates a more comprehensive practice, supported by the health system, of informing previous partners when someone tests positive. “If people know they’re positive, they tend to take precautions against infecting others.”