Over 600 people have been found to not have contracted HIV after using PrEP for two and a half years.
Researchers at the Kaiser Pemanente Medical Center in San Francisco have given over 600 people Truvada to use daily.
No one contracted HIV.
The average age of the study participants was 37, 99% were gay or bisexual men and the average length of individual usage was 7.2 months.
This group was more likely to have multiple sex partners than those who did not use PrEP.
Published in Clinical Infectious Diseases, lead author Jonathan Volk said this is the first time to understand the use of PrEP in a real-world setting.
‘[It] suggests the treatment may prevent new HIV infections even in a high-risk setting,’he said.
‘Until now, evidence supporting the efficacy of PrEP to prevent HIV infection had come from clinical trials and a demonstration project.’
While no one contracted HIV, 30% of participants did get a STI within six months after the study started. This number then jumped to 50% after one year.
In addition, 41% admitted they used condoms less, compared to the 56% who said their use of condoms remained unchanged.
This suggests that many used the drug as a way of not using condoms anymore.
‘Without a control group, we don’t know if these STI rates were higher than what we would have seen without PrEP,’ co-author Julia Marcus said. ‘Ongoing screening and treatments for STIs, including hepatitis C, are an essential component of a PrEP treatment program.’
PrEP has divided the LGBTI community since it was approved by the FDA in 2012.
Michael Weinstein, head of the AIDS Healthcare Foundation, has opposed it, calling Truvada a ‘party drug’ that discourages condom use.
But last year, the World Health Organization suggested that every single sexually active gay and bisexual man should be on the drug saying it could save lives.