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. 2023 Feb;99(1):53-56.
doi: 10.1136/sextrans-2021-055289. Epub 2022 Apr 20.

Non-B subtypes account for a large proportion of clustered primary HIV-1 infections in Italy

Giorgio Bozzi #  1 , Lavinia Fabeni #  2 , Isabella Abbate  2 , Giulia Berno  2 , Antonio Muscatello  3 , Lucia Taramasso  3   4 , Massimiliano Fabbiani  5 , Silvia Nozza  6 , Giuseppe Tambussi  6 , Stefano Rusconi  7   8 , Andrea Giacomelli  7 , Emanuele Focà  9 , Carmela Pinnetti  2 , Gabriella d'Ettorre  10 , Cristina Mussini  11 , Vanni Borghi  11 , Benedetto Maurizio Celesia  12 , Giordano Madeddu  13 , Antonio Di Biagio  14 , Diego Ripamonti  15 , Nicola Squillace  16 , Andrea Antinori  2 , Andrea Gori  3   17 , Maria Rosaria Capobianchi #  2 , Alessandra Bandera #  3   17 ; INACTION study group
Collaborators, Affiliations
Free article

Non-B subtypes account for a large proportion of clustered primary HIV-1 infections in Italy

Giorgio Bozzi et al. Sex Transm Infect. 2023 Feb.
Free article

Abstract

Objectives and design: Using pol sequences obtained for routine resistance testing, we characterised the molecular patterns of HIV-1 transmission and factors associated with being part of a transmission cluster among individuals who in 2008-2014 presented with primary HIV-1 infection (PHI) at 11 urban centres across Italy.

Methods: Pol sequences were obtained by Sanger sequencing. Transmission clusters were identified by phylogenetic analysis (maximum likelihood method, confirmed by Bayesian analysis). Multivariable logistic regression explored factors associated with a participant being part of a transmission cluster.

Results: The PHI cohort comprised 186 participants (159/186, 85.5% males) with median age 44 years, median CD4 count 464 cells/mm3 and median plasma HIV-1 RNA 5.6 log10 copies/mL. Drug resistance associated mutations were found in 16/186 (8.6%). A diversity of non-B subtypes accounted for 60/186 (32.3%) of all infections. A total of 17 transmission clusters were identified, including 44/186 (23.7%) participants. Each cluster comprised 2-6 sequences. Non-B subtypes accounted for seven clusters and 22/44 (50%) of clustered sequences. In multivariable logistic regression analysis, factors associated with being part of a transmission cluster comprised harbouring a non-B subtype (adjusted OR (adjOR) 2.28; 95% CI 1.03 to 5.05; p=0.04) and showing a lower plasma HIV-1 RNA (adjOR 0.80, 95% CI 0.64 to 0.99; p=0.04).

Conclusions: There was a large contribution of diverse non-B subtypes to transmission clusters among people presenting with acute or recent HIV-1 infection in this cohort, illustrating the evolving dynamics of the HIV-1 epidemic in Italy, where subtype B previously dominated.

Keywords: Disease Transmission, Infectious; HIV; MOLECULAR EPIDEMIOLOGY.

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Conflict of interest statement

Competing interests: LT reports past (within 36 months) financial relationships (advisory board membership or consultancy fees, speakers’ honoraria or travel support) with Gilead Sciences, Janssen, Viiv Healthcare and no other conflict of interest. MF reports past (within 36 months) financial relationships (advisory board membership or consultancy fees, speakers’ honoraria or travel support) with Gilead Sciences, Janssen, Viiv Healthcare, BMS, MSD and no other conflict of interest. SR reports past (within 36 months) financial relationships (advisory board membership or consultancy fees, speakers’ honoraria or travel support) with Gilead Sciences, Janssen, Viiv Healthcare and no other conflict of interest. AG reports past (within 36 months) financial relationships (educational support) with Mylan and no other conflict of interest. EF reports past (within 36 months) financial relationships (advisory board membership or consultancy fees, speakers’ honoraria or travel support) with Gilead Sciences, Janssen, Viiv Healthcare, MSD and no other conflict of interest. CP reports past (within 36 months) financial relationships (advisory board membership or consultancy fees, speakers’ honoraria or travel support) with Janssen. GM reports past (within 36 months) financial relationships (advisory board membership or consultancy fees, speakers’ honoraria or travel support) with Gilead Sciences, Janssen, Viiv Healthcare, MSD and no other conflict of interest. AG reports past (within 36 months) grant/research supports, honoraria or consultation fees, speaker’s bureau compensation and/or travel support from Abbvie, Astellas, BMS, Boeringher, Gilead, Janssen, MSD, Novartis, Pfizer, Roche, ViiV and no other conflict of interest.