The discovery emerged in late 2016 even as PrEP is continually used by thousands of people around the world to prevent HIV infections at an estimated rate of 99%. However, it is not 100% at preventing HIV and needs a combination of prevention methods such as the use of condoms.
The study involved a Dutch man aged 50 years engaging in sex with men (MSM). The man was first tested for HIV and then put under PrEP on a daily basis.
The tests included an antibody test which looks for HIV antibodies and an HIV RNA test which is more sensitive to early infections and typically looks for HIV genetic material. Both tests proved that the man was HIV negative before taking part in the study.
After his HIV status was known, the Dutch man was put under PrEP on a daily basis. Study visits and day-to-day daily information showed that he was observing the daily Truvada regimen well.
Even after the start of the PrEP regimen, the man was then tested for HIV using the fourth-generation tests in the first, third, and sixth month of which he tested negative.
Unprotected Sex Cases During Treatment
The man was also expected to keep a record of his sexual encounters where he reported to have engaged in unprotected anal sex with 90 sexual partners in the first 3 months of the study.
He also reported 51 cases of unprotected sex in the next 3 months. However, there was no information documented for the successive 3 month period since the man began showing signs of HIV infection.
Additionally, the man reported having used recreational drugs during his sex escapades which involved crystal meth, cocaine, mephedrone, ketamine and GHB.
How Then did He Get the Virus?
After a period of 8 months on PrEP, the Dutch man began to develop HIV-related symptoms such as fever, pain while urinating as well as difficulty in urinating (dysuria). It is then that the researchers decided to test him for the virus which showed that he had just recently contracted HIV.
Various tests were carried out on the man’s blood which showed peculiar results from the norm. They could not detect the virus at its very early stage.
For fear that the man could develop drug resistance if the man continued to take Truvada, the researchers kept him off the regimen and monitored him on a weekly basis. After three weeks off the PrEP regimen, the man showed very high viral loads which led the researchers to give him a blend of ARV treatment to treat his new HIV infection. Within four weeks, the man’s viral load was undetectable.
Researchers suggested that the man’s high exposure to the virus may have caused a localised infection in his rectum which was kept in check by Truvada. They further continue to say that maybe a drop in Truvada concentration in the rectum without a subsequent drop in blood levels may have provided the opportunity for the localised infection to spread through the body.
The findings of the study were interesting because in this particular case, the virus did not have detectable resistance mutations as compared to the only two other cases of failed PrEP reported before which were highly drug-resistant.
Reference: 2017 Conference on Retroviruses and Opportunistic Infections