Does PrEP change sexual behaviour?
For a while the jury was still out on whether PrEP caused a shift in sexual behavior. The original studies mimicking real-world usage concluded that there was no increase in number of partners or “higher-risk” sexual practices.
However the widespread introduction and increased use of PrEP provided much more data to work with. A recent meta-analysis was conducted on studies performed between 2014 and 2017 to see whether there was an overall change in condom usage or number of sexual partners. They found that across most studies there was a decline in condom usage over time; specifically with regular or casual partners and that more men had reported condomless sex with HIV-positive or HIV-unknown partners. In contrast, researchers found no evidence of increased number of sexual partners in PrEP users across multiple studies.
This most recent data suggests that PrEP does in fact alter some aspects of sexual behavior - specifically in regards to condom usage. However, it is important to point out that new HIV diagnoses in many of these studies have remained virtually non existent in PrEP users with high adherence; demonstrating that PrEP has become an essential part of HIV prevention. 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.
Does PrEP usage lead to increased STI rates?
While correct use of PrEP does decrease the risk of HIV infection, it does not protect against other common STIs such as gonorrhea, syphilis or chlamydia; consistent and correct condom usage is still the best way to prevent these infections.
Perceived risk of HIV infection is decreased in PrEP users, and as a result individuals may ‘compensate’ for this increased protection through less diligent condom usage. This idea has been coined as risk compensation, and has been a major area of interest in research on PrEP. Overall, the consensus findings of recent studies regarding real-world PrEP usage has demonstrated that PrEP is associated with marginal increases in all STI diagnoses and significant increases in rectal STI diagnoses from baseline.
It is important to note that an STI diagnosis does not reduce the efficacy of PrEP. Rather, PrEP provides a unique opportunity to detect and treat STIs early on while still providing protection from HIV. Required testing at frequent intervals for individuals on PrEP may lead to the early diagnosis and treatment of STIs which might have gone undetected and been passed unknowingly to sexual partners otherwise.
Further research is required to fully explore whether increased testing and retention in care positively impacts STI rates. In the meantime, it is important to remember that PrEP is not a wonder-drug that is meant to replace condoms. Rather, it is meant to be used alongside existing strategies as part of a combination approach to improve sexual health outcomes.
Can PrEP be taken during/immediately following pregnancy?
There is limited research on PrEP use in pregnant individuals, however the consensus is that PrEP use during pregnancy and while breastfeeding poses no significant harm to either you or the baby. PrEP can be beneficial in protecting both the mother and infant in situations where there is a substantial risk of acquiring HIV from a partner. Additionally, because there is a chance that HIV can be transmitted via breast milk - specifically right after infection - PrEP usage during breastfeeding can also be beneficial to protect newborns. To learn more about PrEP and pregnancy, visit the Alberta PrEP Guidelines.
Can PrEP be taken with hormones?
PrEP is safe to take while on hormone therapy regimens, and does not demonstrate any adverse interactions. An analysis conducted by the Centre of Excellence for Transgender Health has stated that tenofovir disoproxil fumarate (TDF) and emtricitabine (FTC) are metabolized completely separate from gender-affirming hormones, and thus do not pose a health risk when taken together. A more recent study has shown that hormone levels remain unaffected during PrEP usage. In addition, minimal decreases in TDF blood plasma concentration were observed in patients undergoing hormone therapy; however the level of TDF measured remain above the threshold known to confer protection against HIV. These messages are supported by the Alberta PrEP Guidelines.