The following is a guest post by Daniel Halperin, who is on the faculty of Harvard School of Public Health and is finishing a co-authored book on AIDS. The opinions expressed are his own.

During the biannual International AIDS Conference this week in Vienna, there will be a strong push to increase funding for HIV/AIDS, along with calls to focus more on prevention of it. Given the poor track record of technological advances in HIV prevention, there is eager anticipation about a possible new vaginal gel that could help protect women from getting the virus. While future possibilities, such as the gel, and rhetoric in Vienna are well-intentioned, some of the assertions about AIDS are quite flawed. Here are four key misconceptions about AIDS:

1) Providing AIDS medications to everyone is the best prevention method. A new buzz phrase in the AIDS world is the “test and treat” notion. Some mathematical models have suggested that if tens of millions of people across Africa were tested for HIV, and everyone who tested positive was immediately placed on life-long antiretroviral medications, it would eventually end the epidemic. Such assertions are financially unrealistic, and rely on extremely optimistic and flawed modeling.

Real world evidence, in places such as America and Europe, suggests that although widespread treatment probably helps to reduce the infection rate, it does not eliminate it. So, instead, we should provide life-saving drugs to the people who urgently need them, rather than diverting expensive drugs, which can often have serious side effects, to millions of otherwise healthy individuals for a mainly speculative prevention benefit.

Preliminary research about potential “antiretroviral vaginal gels” will be presented Tuesday in Vienna. Such approaches could eventually help protect some women but, like condoms, they would need to be applied each time prior to sex. The gels may also have long-term toxic side effects and carry the risk that people will stop using more effective methods, like condoms or mutual fidelity, on the assumption they are now “protected” against HIV.