Roberto Rossotti1, Vanni Borghi2, Anna Paola Callegaro3, Valeria Micheli4, Bianca Bruzzone5, Grazia Colao6, Maria Rita Gismondo4, Ilaria Vicenti7, Giovanni Penco8, Maurizio Zazzi7, Stefano Rusconi9. 1. Infectious Diseases Department, ASST GOM "Niguarda", Milan, Italy. Electronic address: Roberto.rossotti@ospedaleniguarda.it. 2. Infectious Diseases Clinics, Azienda Ospedaliero-Universitaria Policlinico, Modena, Italy. 3. Laboratory of Virology and Microbiology, AO Papa Giovanni XXIII Bergamo, Bergamo, Italy. 4. Clinical Microbiology, Virology and Bioemergency, Luigi Sacco Hospital, Milan, Italy. 5. Hygiene Unit, IRCSS A.O.U. San Martino-IST, Genoa, Italy. 6. Laboratory of Virology, Careggi Hospital, Florence, Italy. 7. Department of Medical Biotechnologies, University of Siena, Italy. 8. Infectious Diseases Department, Ente Ospedaliero Ospedali Galliera, Genoa, Italy. 9. Clinic of Infectious Diseases, DIBIC Luigi Sacco, Milan, Italy.
Abstract
BACKGROUND: PrEP with FTC/TDF has shown great efficacy in preventing new HIV infections but issues remain (low adherence, high costs, toxicity and resistance development). No data are available about the impact of circulating Resistance-Associated Mutations (RAMs) on its efficacy. OBJECTIVES: describe the prevalence of FTC and/or TDF-related RAMs in Italian HIV-infected population and their potential impact on PrEP efficacy. STUDY DESIGN: ARCA is a national database that collects data about RAMs and epidemiological correlates from sites throughout Italy; it was queried about the prevalence of these RAMs in the last decade. PrEP efficacy was adjusted for a dynamic score based on RAMs prevalence. Absolute and relative risk increases (ARI and RRI) and number needed to harm (NNH) were calculated after this score. RESULTS: the query retrieved 3579 HAART-naïve and 5781 experienced subjects. Resistance to TDF is low and more common among naïve MSM in the area of Milan (where it topped to 14.3%), without other significant differences. If good adherence is not attained, RRI for receptive anal sex increases by 16% (in naïve) and 93.4% (in experienced MSM). NNH is largely above 10000 except for having receptive anal sex with a HAART-experienced MSM on a failing treatment (970). CONCLUSIONS: according to this model, PrEP may be introduced in Italy without general concerns, but efficacy may be partly reduced in young MSM having sex in Rome and Milan.
BACKGROUND: PrEP with FTC/TDF has shown great efficacy in preventing new HIV infections but issues remain (low adherence, high costs, toxicity and resistance development). No data are available about the impact of circulating Resistance-Associated Mutations (RAMs) on its efficacy. OBJECTIVES: describe the prevalence of FTC and/or TDF-related RAMs in Italian HIV-infected population and their potential impact on PrEP efficacy. STUDY DESIGN: ARCA is a national database that collects data about RAMs and epidemiological correlates from sites throughout Italy; it was queried about the prevalence of these RAMs in the last decade. PrEP efficacy was adjusted for a dynamic score based on RAMs prevalence. Absolute and relative risk increases (ARI and RRI) and number needed to harm (NNH) were calculated after this score. RESULTS: the query retrieved 3579 HAART-naïve and 5781 experienced subjects. Resistance to TDF is low and more common among naïve MSM in the area of Milan (where it topped to 14.3%), without other significant differences. If good adherence is not attained, RRI for receptive anal sex increases by 16% (in naïve) and 93.4% (in experienced MSM). NNH is largely above 10000 except for having receptive anal sex with a HAART-experienced MSM on a failing treatment (970). CONCLUSIONS: according to this model, PrEP may be introduced in Italy without general concerns, but efficacy may be partly reduced in young MSM having sex in Rome and Milan.