PrEP Research

PrEP: Frequently Asked Questions

By now you've probably heard about PrEP's effectiveness. Naturally, that leads to more questions. Is it safe? Who will have access?

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Is it safe?
This is another complicated question to answer, given how much is still unknown. Studies, like Project T and iPrEx, have indicated safety for HIV negative people. However, that comes with a big caveat: only the particular dosage of that specific study medication was proven safe. That doesn’t mean that all doses and all medications will be considered safe. So, if you’re HIV negative, please don’t start taking anti-retroviral medications without talking to a doctor first. If that advice doesn't work for you, make sure you read our best advice.

For PrEP to be used as a prevention tool, further research will be needed to discover the optimal dose to prevent infection and maintain safety. Researchers will also have to study if different doses of PrEP are needed in different populations.  For instance, heterosexual women may need a different dose than gay men or intravenous drug users. Different age groups may also need different doses.

When will we know for sure that it works?
This is a complicated question to answer. Over the next year, there are several trials that will be releasing results that will tell us how a specific product worked within a specific population. 

It’s unlikely that these preliminary studies, however, will answer some of the big picture questions, such as:

• What is the optimal dose of PrEP to take?
• Should women be taking a different dose than men?
• Do people with different risks for HIV need different doses, or different drug formulations?

What seems certain, is that if PrEP is used, it should be used in conjunction with other prevention options, like condom use, routine testing, negotiation with partners and other risk reduction strategies.

What are the known side effects of PrEP?
One study, Project T, used the drug tenofovir, an anti-retroviral drug usually used to treat HIV.  Side effects of tenofovir for HIV treatment are minimal and are generally limited to nausea and loss of appetite. A small percentage of individuals taking tenofovir have reported more serious problems such as kidney function problems or reduction in bone density.  Among HIV negative trial participants as part of this study, no serious side effects were found in the analysis of kidney function and bone density.

The side effect profile for PrEP will be determined by both the medications that are used, as well as the dosages and how often the medications are taken.  Right now, we just don’t know what those could be.

Who will have access to PrEP?
Right now, using anti-retroviral medications to prevent HIV infections is something that hasn’t been approved by the FDA.  A doctor would have to be willing to prescribe the drugs for off-label purpose. So, if PrEP is found to work, it’s a matter of waiting for FDA approval and/or doctors being willing to prescribe it.

Another matter is the cost.  One estimate from a local pharmacy is that Truvada costs $12,000 a year without insurance coverage. If insurance or other providers cover that cost, people may be able to access PrEP.  But with budgets tight, it’s hard to know who will step up to pay the cost. 

One way of bringing down the cost is by using intermittent dosing, meaning that people would take the drug less than daily. One study is looking to see whether it’s feasible for people to take Truvada twice a week and after sex. Studies that test whether intermittent dosing is effective for preventing HIV will not be complete for some time.

Should I change what I’m doing to stay HIV negative?
It’s definitely good to be informed of new technologies coming down the pipeline. As of now, a safe and effective PrEP regimen has yet to be determined. Therefore, it is not a replacement for current prevention strategies. CDC has recently released guidelines for PrEP use for men who have sex with men.

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