We discovered a highly virulent variant of subtype-B HIV-1 in the Netherlands. One hundred nine individuals with this variant had a 0.54 to 0.74 log 10 increase (i.e., a ~3.5-fold to 5.5-fold increase) in viral load compared with, and exhibited CD4 cell decline twice as fast as, 6604 individuals with other subtype-B strains. Without treatment, advanced HIV—CD4 cell counts below 350 cells per cubic millimeter, with long-term clinical consequences—is expected to be reached, on average, 9 months after diagnosis for individuals in their thirties with this variant. Age, sex, suspected mode of transmission, and place of birth for the aforementioned 109 individuals were typical for HIV-positive people in the Netherlands, which suggests that the increased virulence is attributable to the viral strain. Genetic sequence analysis suggests that this variant arose in the 1990s from de novo mutation, not recombination, with increased transmissibility and an unfamiliar molecular mechanism of virulence.

Background Sexually transmitted acute hepatitis C virus (HCV) infections (AHIs) have been mainly described in human immunodeficiency virus (HIV)–infected men who have sex with men (MSM). Cases in HIV-negative MSM are scarce. We describe the epidemic of AHI in HIV-infected and HIV-negative MSM in Lyon, France. Methods All cases of AHI diagnosed in MSM in Lyon University Hospital from 2014 to 2017 were included. AHI incidence was determined in HIV-infected and in preexposure prophylaxis (PrEP)–using MSM. Transmission clusters were identified by construction of phylogenetic trees based on HCV NS5B (genotype 1a/4d) or NS5A (genotype 3a) Sanger sequencing. Results From 2014 to 2017, 108 AHIs (80 first infections, 28 reinfections) were reported in 96 MSM (HIV-infected, 72; HIV-negative, 24). AHI incidence rose from 1.1/100 person-years (95 confidence interval [CI], 0.7–1.7) in 2014 to 2.4/100 person-years (95 CI, 1.1–2.6) in 2017 in HIV-infected MSM (P = .05) and from 0.3/100 person-years (95 CI, 0.06–1.0) in 2016 to 3.4/100 person-years (95 CI, 2.0–5.5) in 2017 in PrEP users (P < .001). Eleven clusters were identified. All clusters included HIV-infected MSM; 6 also included HIV-negative MSM. All clusters started with ≥1 HIV-infected MSM. Risk factor distribution varied among clusters. Conclusions AHI incidence increased in both HIV-infected and HIV-negative MSM. Cluster analysis suggests initial transmission from HIV-infected to HIV-negative MSM through chemsex and traumatic sexual practices, leading to mixed patterns of transmission regardless of HIV status and no overlap with the general population.

Intravenous ZDV remains an effective tool to reduce transmission in cases of virological failure, even in cART-treated women. However, for the vast majority of women with low viral loads at delivery, in the absence of obstetrical risk factors, systematic intravenous ZDV appears to be unnecessary.

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