Ask the Doc: PrEP Resistance, and STIs

EDGE introduces Dr. Peter Meacher, MD FAAFP AAHIVS, our new resident medical professional who will be writing the Ask the Doc column. Today's column deals with PrEP resistance and STIs.

Pre-exposure prophylaxis, or PrEP, has been a real game-changer for men who have sex with men (MSM) and other people at risk for HIV infection.

Truvada does a tremendous job keeping people who engage in high-risk sexual activities from contracting HIV. But with recent news that two men on PrEP were infected with HIV, some are expressing concerns about resistance.

In addition, the rise in PrEP use has also been associated with a concurrent rise in other STIs and hepatitis, possibly due to a decline in condom use among that cohort.

In this edition of Ask the Doc, Dr. Meacher addresses these issues, sharing some important facts about PrEP use, resistance, and issues around foregoing condom use while on this regimen.

As always, consult your physician before making any changes to your HIV regimen. This general information is not intended to diagnose any medical condition or to replace your healthcare professional.

How Well Does PrEP Really Work?

Q. I am taking PrEP to prevent HIV, but recently read that two men got HIV while taking PrEP daily anyway. Should I even bother?

A. No treatment is perfect and PrEP is no different, but this does not mean we should throw the proverbial PrEP baby out with the bathwater. Here's why: there are 80,000 people (and counting) known to have been prescribed PrEP. Of these 80,000, only two are known to have been infected with HIV.

This confirms that it is possible to become infected with a strain of virus that is resistant to the drugs in Truvada, but not likely. And if you take those numbers and contrast with the 50,000 people infected with HIV each year, the importance of PrEP as an effective prevention tool to help stop the epidemic is clear.

But as a cautionary tale, here's what we also know: taking PrEP as it is prescribed is crucial for it to work effectively. Although there appears to be some forgiveness, taking PrEP regularly (daily is optimal) is the most important factor in ensuring PrEP works and should remain the goal for patients on PrEP.

Researchers have estimated that those who take Truvada at least four times a week are more than 99 percent protected against HIV. It is also important to know that daily PrEP is only fully effective after taking it daily for 7 days before anal sex and 21 days for receptive vaginal sex.

So adherence, combined with regular testing (every 3 months) will help you stay on top of your health and catch any problems.

A Lot of Guys on PrEP Don't Use Condoms. Is This Safe?

Q. I'm living in San Francisco where a lot of guys are on PrEP to prevent contracting HIV. That means hardly anyone wears condoms anymore. Is this safe?

A. Safety is relative. What are you doing and who are you doing it with? What are they doing? Are you topping or bottoming? Are you wearing condoms sometimes, or never? If you're on PrEP, are you taking it regularly (see above)?

For those who didn't wear condoms before or after using PrEP, PrEP is a tremendous tool to protect from infection with HIV; and if you do use condoms, PrEP is an added layer of protection. However PrEP does not protect against pregnancy or STDs.

Therefore HIV and STD testing is required every 3 months for those on PrEP -- a more regular testing schedule than that of most sexually active adults. Some researchers say this accounts for the apparent 'rise' in STD infections -- they aren't actually rises, they're just being reported more often. Luckily, this means they're also being caught and treated earlier.

To fully protect against STDs, anyone on PrEP should also wear condoms. If you're not, try to reduce your risk by not using or limiting drugs and/or alcohol with sex to ensure you're as safe as possible; and get tested regularly to treat anything you might be infected with, to help prevent the spread of STDs to other partners.