There are many myths and misconceptions around PrEP. Let’s address two of the largest ones.
PrEP will Lead to Riskier Sex
Several PrEP studies, which mimicked real world usage, addressed these concerns by looking at the changes in sexual behaviour of PrEP users. The iPrEX and IPERGAY studies found that there was actually a general trend towards fewer sexual partners amongst PrEP users, with no increase in “high-risk” sexual practices (and here). The PROUD study reported similar findings, with no significant increase in the number of sexual partners amongst PrEP users.
In terms of condom usage, the PROUD study, along with a trial conducted by the Centers for Disease Control, reported that instances of condomless intercourse either remained unchanged or decreased for PrEP users during the study period. While the majority of participants in the PROUD study reported a decrease in the number of condomless sexual encounters, there was a small subset of men who reported engaging in condomless sex with a larger number of sexual partners at one year of follow-up. This increase in the number of condomless sexual encounters, however, was not associated with a higher number of STI diagnoses. Both studies corroborated previous findings regarding the introduction of pharmaceutical prevention strategies.
To conclude, although increased data from real-world PrEP use will continue to inform our understanding of PrEP’s impact on sexual behaviour, there does not appear to be a clear link between PrEP use and an increase in sexual “risk-taking” amongst most PrEP users. Instead, those who choose to take PrEP are often already engaging in sexual behaviours that place them at a higher risk of HIV infection and PrEP simply provides them with additional protection or a more suitable HIV prevention method to serve their current sexual health needs.
PrEP Leads to Increases in STI Rates
While correct use of PrEP does decrease the risk of HIV infection, it does not protect against other common STIs such as gonorrhoea, syphilis or chlamydia; consistent and correct condom usage is still the best way to prevent these infections.
In addition to examining the efficacy and safety of PrEP, previous studies have also compared the number of STI diagnoses between PrEP users and those not taking PrEP to determine if there was a measurable increase in the number of bacterial STIs (syphilis, gonorrhoea, chlamydia) amongst those taking PrEP. Both the PROUD and IPERGAY studies reported no significant differences in the number of reported STIs between the two groups.
On the other hand, there have been some analyses which have reported an increase in the total number of STI diagnoses amongst PrEP users. With no control group of non-PrEP users to compare the data to, however, the significance of the data is limited and the increase in STIs cannot be attributed solely to the use of PrEP. Therefore, further research will need to be undertaken to truly establish whether or not increased PrEP use will lead to an increase in other STIs in the real world.
In the meantime, PrEP does provide a unique opportunity as it relates to the prevention and control of STIs. Recommended monitoring and follow-up for PrEP users requires regular STI screening to assist in the early detection of STIs. When STIs are diagnosed early they can also be treated early, meaning there is less opportunity for them to be passed on to other sexual partners. Therefore, the increased frequency of testing amongst PrEP users can actually have a positive impact on STI rates, ensuring that those on PrEP are being diagnosed and treated early as opposed to carrying STIs for a longer period of time and unknowingly passing them onto their sexual partners.
Finally, regardless of the challenges we face controlling STI rates, it does not change the fact that certain communities within Nova Scotia continue to experience high rates of new HIV infections. Nor does it change the fact that when PrEP is used as prescribed it is nearly 100% effective in preventing those infections. So, yes, we must address the potential impacts of expanded PrEP use on STI rates. However, concerns about STI rates are not a valid reason to withhold an effective prevention option that can prevent new – incurable – HIV infections.