Jonathan Volk’s group at Kaiser Permanente in California followed a group of outpatients who began taking PrEP (pre-exposure prophylaxis) in order to reduce their risk of contracting HIV. PrEP is sold as Truvada, a drug sold by Gilead Pharmaceuticals to treat HIV infection, although the FDA recently gave its approval to use Truvada to prevent HIV infection in high risk individuals. Volk’s group enrolled subjects (99% of whom were men who have sex with men) over the course of 2.5 years – ultimately enrolling 657 PrEP-initiators. 388 person years of PrEP use were observed, with an individual mean duration of PrEP use of 7.2 months. And their results were astounding.
There were zero HIV infections in PrEP users during the 2.5 year period. Yes… ZERO.
These days, that’s almost unheard of in science and medicine. And it’s pretty amazing. The study is the first real world study of PrEP use, as opposed to a rigorous clinical trial, and shows that PrEP is actually, and astoundingly, effective for preventing HIV transmission.
The only downside? After 6 months of PrEP use, 30% of users in the study were diagnosed with at least one STI; after 12 months, that increased to 50% of those still using PrEP – a finding that PrEP critics suggest supports their arguments that PrEP promotes irresponsible sexual practices, declining condom use, and rising rates of other STIs.
The battle over the best way to prevent HIV will continue to rage on, with critics and supporters on both sides of the issue. Our whole lives, we’ve been taught that the only way to truly prevent HIV transmission is through abstinence, as even condoms have a 1-2% failure rate. Well… now there might be another way. More exciting – PrEP could herald the beginning of the end of the HIV era as we know it. Only time will tell.