Preventive efficacy of tenofovir/emtricitabine against SARS-CoV-2 among PREP users

Background The preventive effect which tenofovir/emtricitabine could have against SARS-CoV-2 in HIV-negative people is unknown. The objective of this study was to analyse the seroprevalence and clinical manifestations of COVID-19 among users of PrEP, TDF/FTC or TAF/FTC, and to compare it to that of a control group. Methods Observational descriptive study of the seroprevalence of antibodies for SARS-CoV-2 among men who have sex with men and transgender women without use of PrEP(Group1;n=250) and PrEP users with TDF/FTC(n=409) or TAF/FTC(n=91) (Group2;n=500), conducted from 11-May-2020 to 27-Jun-2020. All were provided with a structured questionnaire which collected information on the variables to be analysed and testing for IgG antibodies to SARS-CoV-2 (CMIA) was then carried out. Results The seroprevalence of SARS-CoV-2 was 9·2%(95% CI: 5·9-13·5) in the group without PrEP and 15.0%(95% CI: 12·0-18·4) in the group with PrEP(p=0·026). Among users of TDF/FTC it was 14.7%(95% CI: 11·4-18·5) and in users of TAF/FTC it was 16·5%(95% CI: 9·5-25·7)(p=0·661). In those positive for SARS-CoV-2 receiving PrEP, 57·4% manifested symptoms compared to 78·3% in the control group (p=0·070). In users of TDF/FTC the figure was 53·3% and TAF/FTC 73·3%(p=0·100). The duration of symptoms was 11·5 days in the control group, 9·0 in PrEP users(p=0·116), 7·0 in users of TDF/FTC and 13·0 in users of TAF/FTC(p = 0·100). Conclusion Users of PrEP, TDF/FTC or TAF/FTC presented a higher seroprevalence to SARS-CoV-2 than the control group. No statistically significant differences were found in relation to clinical manifestations. PrEP users should use the same prevention measures as those indicated for the general population.