Data linkage to evaluate the long-term risk of HIV infection in individuals seeking post-exposure prophylaxis. Nature Communications
Hovaguimian et al. aimed to estimate the long-term risk of HIV infection in post-exposure prophylaxis (PEP-) seekers in a tertiary referral center. As previous evidence suggests that sexual risk taking occurs in phases lasting 12 to 24 months, they hypothesized that HIV infections would be clustered shortly after the time of PEP consultation.
Overall, there were 975 PEP-seekers between 2007 and 2013. Using privacy preserving probabilistic linkage, the authors linked these 975 records with two observational databases providing data on HIV events, the Zurich Primary HIV Infection study and the Swiss HIV Cohort Study, respectively. With this approach, they identified 22 HIV infections and obtained long-term follow-up data, which reveal a median of 4.1 years between consultation for post-exposure prophylaxis and HIV diagnosis. Even though men who have sex with men constituted only 35.8% of those seeking post-exposure prophylaxis, all 22 events occur in this subgroup.
In conclusion, in this retrospective data linkage study, the proportion of PEP seekers tested positive for HIV after PEP intake was 2.3%, and this proportion reached 6.3% in MSM. This study identified that most seroconversions occurred 4 years after PEP consultation, thereby bringing long-term insights into the risk of contracting HIV following PEP seeking. Those who seroconverted were all MSM, which should strongly encourage early consideration of PrEP in MSM after a first episode of PEP.