Factors affecting transmission of mucosal human papillomavirus

Human papillomavirus (HPV) is the most common sexually transmitted infection. The effect of HPV on public health is especially related to the burden of anogenital cancers, most notably cervical cancer. Determinants of exposure to HPV are similar to those for most sexually transmitted infections, but determinants of susceptibility and infectivity are much less well established. Gaps exist in understanding of interactions between HPV, HIV, and other sexually transmitted infections. The roles of mucosal immunology, human microbiota at mucosal surfaces, host genetic factors and hormonal concentrations on HPV susceptibility and infectivity are poorly understood, as are the level of effectiveness of some primary or secondary preventive measures other than HPV vaccination (such as condoms, male circumcision, and combination antiretroviral therapy for HIV). Prospective couples studies, studies focusing on mucosal immunology, and in-vitro raft culture studies mimicking HPV infection might increase understanding of the dynamics of HPV transmission.

Effectiveness of bivalent mRNA booster vaccination against SARS-CoV-2 Omicron infection, the Netherlands, September to December 2022

We used data of 32,542 prospective cohort study participants who previously received primary and one or two monovalent booster COVID-19 vaccinations. Between 26 September and 19 December 2022, relative effectiveness of bivalent original/Omicron BA.1 vaccination against self-reported Omicron SARS-CoV-2 infection was 31% in 18-59-year-olds and 14% in 60-85-year-olds. Protection of Omicron infection was higher than of bivalent vaccination without prior infection. Although bivalent booster vaccination increases protection against COVID-19 hospitalisations, we found limited added benefit in preventing SARS-CoV-2 infection.

Antimicrobial susceptibility patterns amongst group B streptococci from women in Harare, Zimbabwe

As part of a larger study of vaginal pathogens in women in Harare, we have examined the antimicrobial susceptibility patterns of 130 isolates of group B streptococci (GBS). These organisms are important because of their association with preterm labour, premature rupture of membranes and neonatal sepsis. All of the isolates in Harare were fully sensitive to beta-lactams, with an MIC(90) for ampicillin of 0.38 mg/l, but five isolates were resistant in vitro to erythromycin, and each of these had an MIC >4 mg/l. Seven isolates showed resistance to clindamycin. Some isolates showed an intermediate sensitivity to gentamicin, but the great majority were resistant to this antibiotic. Studies in developed countries have shown that an intervention strategy, using intrapartum chemoprophylaxis, is effective in reducing the incidence of complications of GBS colonization in pregnant women. Our data suggest that ampicillin would be a suitable antibiotic for use in an intervention programme of intrapartum chemoprophylaxis in Harare.

Prospective cohort study of fatigue before and after SARS-CoV-2 infection in the Netherlands

Fatigue is one of the most common persistent symptoms of SARS-CoV-2 infection. We aimed to assess fatigue during and after a SARS-CoV-2 infection by age, sex, presence of a medical risk condition, SARS-CoV-2 variant and vaccination status, accounting for pre-infection fatigue and compared with uninfected individuals. We used data from an ongoing prospective cohort study in the Netherlands (VASCO). We included 22,705 first infections reported between 12 July 2021 and 9 March 2024. Mean fatigue scores increased during infection, declined rapidly in the first 90 days post-infection, but remained elevated until at least 270 days for Delta and 120 days for Omicron infections. Prevalence of severe fatigue was 18.5% before first infection. It increased to 24.4% and 22.5% during acute infection and decreased to 21.2% and 18.9% at 90 days after Delta and Omicron infection, respectively. The prevalence among uninfected participants was lower than among matched Delta-infected participants during the acute phase of the infection and 90 days post-infection. For matched Omicron-infected individuals this was only observed during the acute phase. We observed no differences in mean post- vs pre-infection fatigue scores at 90-270 days post-infection by vaccination status. The impact of SARS-CoV-2 infection on the prevalence of severe fatigue was modest at population level, especially for Omicron.

Effectiveness of Omicron XBB.1.5 vaccine against infection with SARS-CoV-2 Omicron XBB and JN.1 variants, prospective cohort study, the Netherlands, October 2023 to January 2024

We estimated vaccine effectiveness (VE) of SARS-CoV-2 Omicron XBB.1.5 vaccination against self-reported infection between 9 October 2023 and 9 January 2024 in 23,895 XBB.1.5 vaccine-eligible adults who had previously received at least one booster. VE was 41% (95% CI: 23-55) in 18-59-year-olds and 50% (95% CI: 44-56) in 60-85-year-olds. Sequencing data suggest lower protection against the BA.2.86 (including JN.1) variant from recent prior infection (OR = 2.8; 95% CI:1.2-6.5) and, not statistically significant, from XBB.1.5 vaccination (OR = 1.5; 95% CI:0.8-2.6).

Vaginal bacterium Prevotella timonensis turns protective Langerhans cells into HIV-1 reservoirs for virus dissemination

Dysbiosis of vaginal microbiota is associated with increased HIV-1 acquisition, but the underlying cellular mechanisms remain unclear. Vaginal Langerhans cells (LCs) protect against mucosal HIV-1 infection via autophagy-mediated degradation of HIV-1. As LCs are in continuous contact with bacterial members of the vaginal microbiome, we investigated the impact of commensal and dysbiosis-associated vaginal (an)aerobic bacterial species on the antiviral function of LCs. Most of the tested bacteria did not affect the HIV-1 restrictive function of LCs. However, Prevotella timonensis induced a vast uptake of HIV-1 by vaginal LCs. Internalized virus remained infectious for days and uptake was unaffected by antiretroviral drugs. P. timonensis-exposed LCs efficiently transmitted HIV-1 to target cells both in vitro and ex vivo. Additionally, P. timonensis exposure enhanced uptake and transmission of the HIV-1 variants that establish infection after sexual transmission, the so-called Transmitted Founder variants. Our findings, therefore, suggest that P. timonensis might set the stage for enhanced HIV-1 susceptibility during vaginal dysbiosis and advocate targeted treatment of P. timonensis during bacterial vaginosis to limit HIV-1 infection.