Retrospective Seroprevalence of Orthopoxvirus Antibodies among Key Populations, Kenya.

We identified a cluster of mpox exposures among key populations in Kenya through retrospective serologic screening. We identified strong seropositivity among sex workers and gay, bisexual, and other men who have sex with men. These findings demonstrate the need for increased mpox surveillance among mpox-endemic and mpox-endemic-adjacent regions in Africa.

Clade I-Associated Mpox Cases Associated with Sexual Contact, the Democratic Republic of the Congo.

We report a cluster of clade I monkeypox virus infections linked to sexual contact in the Democratic Republic of the Congo. Case investigations resulted in 5 reverse transcription PCR-confirmed infections; genome sequencing suggest they belonged to the same transmission chain. This finding demonstrates that mpox transmission through sexual contact extends beyond clade IIb.

Presumed Transmission of 2 Distinct Monkeypox Virus Variants from Central African Republic to Democratic Republic of the Congo.

We linked 4 mpox cases in South Ubangi, Democratic Republic of the Congo, to transboundary transmission from Central African Republic. Viral genome sequencing demonstrated that the monkeypox virus sequences belonged to distinct clusters of subclade Ia. This finding demonstrates the borderless nature of mpox and highlights the need for vigilant regional surveillance.

Describing the effect of COVID-19 on sexual and healthcare-seeking behaviours of men who have sex with men in three counties in Kenya: a cross-sectional study.

BACKGROUND: While the COVID-19 pandemic disrupted HIV preventative services in sub-Saharan Africa, little is known about the specific impacts the pandemic has had on men who have sex with men (MSM) in Kenya. METHODS: Data were from an HIV self-testing intervention implemented in Kisumu, Mombasa and Kiambu counties in Kenya. Baseline data collection took place from May to July 2019, and endline in August-October 2020, coinciding with the lifting of some COVID-19 mitigation measures. Using endline data, this study characterised the impact the pandemic had on participants' risk behaviours, experience of violence and behaviours related to HIV. Logistic regression was used to understand factors related to changes in risk behaviours and experiences of violence; adjusted AORs (AORs) and 95% CIs are reported. RESULTS: Median age was 24 years (IQR: 21-27). Most respondents (93.9%) reported no change or a decrease in the number of sexual partners (median number of male sexual partners: 2, IQR: 2-4). Some participants reported an increase in alcohol (10%) and drug (16%) consumption, while 40% and 28% reported decreases in alcohol and drug consumption, respectively. Approximately 3% and 10% reported an increase in violence from intimate partners and police/authorities, respectively. Compared with those with primary education, those with post-secondary education were 60% less likely to report an increase in the number of male sexual partners per week (AOR: 0.4, 95% CI: 0.2 to 0.9), while those who were HIV positive were at twofold the odds of reporting an increase or sustained levels of violence from intimate partners (AOR: 2.0, 95% CI: 1.1 to 4.0). CONCLUSION: The results of this study demonstrate heterogeneity in participants' access to preventative HIV and clinical care services in Kenya after the onset of the COVID-19 epidemic. These results indicate the importance of responding to specific needs of MSM and adapting programmes during times of crisis.

Riding high: seroprevalence of SARS-CoV-2 after 4 pandemic waves in Manitoba, Canada, April 2020-February 2022.

BACKGROUND: Canada is emerging from the largest SARS-CoV-2 Omicron wave to date, with over 3.3 million confirmed cases. Unfortunately, PCR confirmed cases illuminate only a small portion of infections in the community and underestimate true disease burden. Population based seroprevalence studies, which measure antibody levels against a virus can more accurately estimate infection rates in the community and identify geographical and epidemiological trends to inform public health responses. METHODS: The Manitoba COVID-19 Seroprevalence (MCS) study is a population-based cross-sectional study to assess the prevalence of SARS-CoV-2 antibodies across the province. Residual convenience specimens (n = 14,901) were tested for anti-SARS-CoV-2 nucleocapsid and spike IgG antibodies from April 1, 2020 to February 31, 2022. We estimated the monthly and cumulative prevalence using an exponential decay model, accounting for population demographics, sensitivity/specificity, and antibody waning. This approach generated estimates of natural infection as well as total antibody including vaccine-induced immunity within the community. FINDINGS: After four waves of the pandemic, 60.1% (95%CI-56.6-63.7) of Manitobans have generated SARS-CoV-2 antibodies due to natural exposure independent of vaccination. Geographical analysis indicates a large portion of provincial prevalence stems from increased transmission in the Northern (92.3%) and Southern (71.8%) regional health authorities. Despite the high mortality rates reported by Manitoba, infection fatality ratios (IFR) peaked at 0.67% and declined to 0.20% following the Omicron wave, indicating parity with other national and international jurisdictions. Manitoba has achieved 93.4% (95%CI- 91.5-95.1) total antibody when including vaccination. INTERPRETATION: Our data shows that more than 3 in 5 Manitobans have been infected by SARS-CoV-2 after four waves of the pandemic. This study also identifies key geographical and age specific prevalence rates that have contributed greatly to the overall severity of the pandemic in Manitoba and will inform jurisdictions considering reduction of public health measures.

A cross-sectional survey exploring HIV and HCV prevalence among men who purchase sex in Dnipro, Ukraine.

BACKGROUND: HIV programming in Ukraine largely targets "key population" groups. Men who purchase sex are not directly reached. The aim of our study was to explore the prevalence of sexually transmitted and blood-borne infections (STBBIs) among men who purchase sex from female sex workers. METHODS: Following geographic mapping and population size estimation at each "hotspot", we conducted a cross-sectional bio-behavioural survey with men who purchase sex between September 2017 and March 2018 in Dnipro, Ukraine. Eligibility criteria included purchasing sex services at a "hotspot" and being ≥ 18 years. Participants completed a structured questionnaire, followed by HIV/HCV rapid testing and a dried blood spot (DBS) sample collection for confirmatory serology. RESULTS: The study enrolled 370 participants. The median age was 32 (interquartile range [IQR] = 27-38) and the median age of first purchase of sexual services was 22 (IQR = 19-27). Over half (56%) of participants reported ever testing for HIV; four participants (2%, N = 206) reported having tested positive for HIV, with three out of the four reporting being on ART. Forty percent of participants had ever tested for HCV, with three (2%, N = 142) having ever tested positive for HCV. In DBS testing, nine participants (2.4%) tested positive for HIV and 24 (6.5%) tested positive for ever having an HCV infection. CONCLUSION: Prevalence of HIV and HCV in this population was high. Given high rates of study enrolment and testing, efforts should be made to reach men who purchase sex with expanded STBBI programming.

Comparing the Ecological Niches of Chlamydial and Gonococcal Infections in Winnipeg, Canada: 2007-2016.

BACKGROUND: Previous studies have shown substantial differences in geographic clustering of sexually transmitted infections (STI), such as chlamydia (CT) and gonorrhea (NG), conditional on epidemic phase. Chlamydia and NG have recently shown resurgent epidemiology in the northern hemisphere. This study describes the recent epidemiology of CT and NG in Winnipeg, Canada, combining traditional surveillance tools with place-based analyses, and comparing the ecological niches of CT and NG, in the context of their evolving epidemiology. METHODS: Data were collected as part of routine public health surveillance between 2007 and 2016. Secular trends for CT and NG, and CT/NG coinfection were examined. Gini coefficients and population attributable fractions explored the distribution, and concentration of infections over time and space. RESULTS: Rates of CT increased from 394.9/100,000 population to 476.2/100,000 population from 2007 to 2016. Gonorrhea rates increased from 78.0/100,000 population to 143.5/100,000 population during the same period. Each pathogen had its own ecological niche: CT was widespread geographically and socio-demographically, while NG was clustered in Winnipeg's inner-core. CT/NG co-infections had the narrowest space and age distribution. NG was shown to be undergoing a growth phase, with clear signs of geographic dispersion. The expansion of NG resembled the geographic distribution of CT. CONCLUSIONS: We demonstrated that NG was experiencing a growth phase, confirming theoretical predictions of geographic dispersion during a growth phase. During this phase, NG occupied similar geographic spaces as CT. Knowledge of different ecological niches could lead to better targeting of resources for subpopulations vulnerable to STIs.

Prior history of testing for syphilis, hepatitis B and hepatitis C among a population-based cohort of HIV-positive individuals and their HIV-negative controls.

Understanding patterns of serological testing for hepatitis B & C, and syphilis among HIV-positive individuals, prior to HIV diagnosis, can inform HIV diagnosis, engagement and prevention strategies. This was a population-based, retrospective analysis of prior serological testing among HIV-positive individuals in Manitoba, Canada. HIV cases were age-, sex- and region-matched to HIV-negative controls at a 1:5 ratio. Conditional logistic regression was used to examine previous serological tests and HIV status. Odds ratios (ORs) and their 95% confidence intervals (95% CI) were reported. A total of 193 cases and 965 controls were included. In the 5 years prior to diagnosis, 50% of cases had at least one test, compared to 26% of controls. Compared to those who did not have serological testing in the 5 years prior to HIV infection, those who had one serological test were at twice the odds of being HIV positive (OR: 1.9, 95% CI: 1.2-2.9), while those with 2 or more tests were at even higher odds (OR: 5.5, 95%CI: 3.7-8.4). HIV cases had higher serological testing rates. Interactions between public health and other healthcare providers should be strengthened.

Teen clinics: missing the mark? Comparing pregnancy and sexually transmitted infections rates among enrolled and non-enrolled adolescents.

BACKGROUND: In Manitoba, Canada, school-based clinics providing sexual and reproductive health services for adolescents have been implemented to address high rates of sexually transmitted infections (STIs) and pregnancies. METHODS: The objectives of this population-based study were to compare pregnancy and STI rates between adolescents enrolled in schools with school-based clinics, those in schools without clinics, and those not enrolled in school. Data were from the PATHS Data Resource held in the Population Health Research Data Repository housed at the Manitoba Centre for Health Policy. Adolescents aged 14 to 19 between 2003 and 2009 were included in the study. Annualized rates of pregnancies and positive STI tests were estimated and Poisson regression models were used to test for differences in rates amongst the three groups. RESULTS: As a proportion, pregnancies among non-enrolled female adolescents accounted for 55 % of all pregnancies in this age group during the study period. Pregnancy rates were 2-3 times as high among non-enrolled female adolescents. Compared to adolescents enrolled in schools without school-based clinics, age-adjusted STI rates were 3.5 times (p < .001) higher in non-enrolled males and 2.3 times (p < .001) higher in non-enrolled females. CONCLUSIONS: The highest rates for pregnancies and STIs were observed among non-enrolled adolescents. Although provision of reproductive and health services to in-school adolescents should remain a priority, program planning and design should consider optimal strategies to engage out of school youth.

Risk Factors for HIV Acquisition in a Prospective Nairobi-Based Female Sex Worker Cohort.

With two million new HIV infections annually, ongoing investigations of risk factors for HIV acquisition is critical to guide ongoing HIV prevention efforts. We conducted a prospective cohort analysis of HIV uninfected female sex workers enrolled at an HIV prevention clinic in Nairobi (n = 1640). In the initially HIV uninfected cohort (70 %), we observed 34 HIV infections during 1514 person-years of follow-up, i.e. an annual incidence of 2.2 % (95 % CI 1.6-3.1 %). In multivariable Cox Proportional Hazard analysis, HIV acquisition was associated with a shorter baseline duration of sex work (aHR 0.76, 95 % CI 0.63-0.91), minimum charge/sex act (aHR 2.74, 0.82-9.15, for low vs. intermediate; aHR 5.70, 1.96-16.59, for high vs. intermediate), N. gonorrhoeae infection (aAHR 5.89, 95 % CI 2.03-17.08), sex with casual clients during menses (aHR 6.19, 95 % CI 2.58-14.84), Depo Provera use (aHR 5.12, 95 % CI 1.98-13.22), and estimated number of annual unprotected regular partner contacts (aHR 1.004, 95 % CI 1.001-1.006). Risk profiling based on baseline predictors suggested that substantial heterogeneity in HIV risk is evident, even within a key population. These data highlight several risk factors for HIV acquisition that could help to re-focus HIV prevention messages.

Fertility intentions, power relations and condom use within intimate and other non-paying partnerships of women in sex work in Bagalkot District, South India.

This study aimed to: (1) examine the relationship between interpersonal as well as social-demographic, cultural and structural factors, and condom non-use by sex workers' main intimate or other non-paying male sex partners (NPPs), as reported by a sample of sex workers (SWs); and (2) understand HIV/sexually transmitted infections (STIs) risk (e.g., numbers of sexual partners; condom use with different partners) among couples comprised of a sub-set of SWs and their NPPs. Bivariate and multivariable logistic regression was used to identify factors associated with condom non-use at last sex by the main NPP, as reported by SWs. Adjusted odds ratios and 95% confidence intervals are reported (AOR[95%CIs]). Data were drawn from cross-sectional surveys in Bagalkot District, Karnataka State, South India. Responses by SWs whose main NPPs agreed to enrol in the study and the main NPP enroled were linked; these responses by couples (pairs of SWs and NPPs) were examined to assess sexual risk for HIV/STIs. Overall, this study included 257 SWs and 76 NPPs. The data from 67 couples (88.2%) could be linked. In over a quarter of partnerships, at least one (SW or NPP) partner reported having another type of partner besides each other (and clients of SWs). In multivariable analysis, significantly increased odds of condom non-use at last sex with the main NPP were found for the following key factors: planning to have a child with their main NPP (AOR = 3.71[1.44-9.58]); and having decisions about condom use made by their main NPP (AOR = 9.87[4.03-24.16]) or both equally (AOR = 3.18[1.39-7.80]) (versus by the SWs herself). Our study highlights the potential risk for HIV/STI acquisition and transmission between NPPs and SWs, and between NPPs and their non-SWs wives and other sex partners. Study results underscore the need for HIV/STI prevention approaches that incorporate informed decision-making about childbearing and parenting, and empowerment strategies for SWs in the context of their relationships with NPPs.

Association between spring season of birth and Crohn's disease.

BACKGROUND & AIMS: As for many complex diseases, the incidence of inflammatory bowel disease (IBD) is higher among individuals born during certain seasons. This difference could arise from seasonal variations in many factors, including exposure to sunlight, antibiotics, or infectious agents. We investigated the relationship between season of birth, early childhood exposure to antibiotics, and incidence of IBD. METHODS: We performed a nested case-control analysis using data from the University of Manitoba inflammatory bowel disease epidemiology database. We compared seasons of birth among 11,145 individuals with IBD (cases) and 108,633 controls using conditional logistic regression models. We collected data on use of antibiotics in the first year of life for cases and controls from the Manitoba Drug Program Information Network-a comprehensive database of all prescriptions given to residents of Manitoba since 1995. RESULTS: Approximately 27.0% of cases were born from April through June, compared with 25.6% of controls (odds ratio, 1.07; 95% confidence interval, 1.02-1.12; P = .002). Comparisons made by sex (male vs female) and type of IBD (ulcerative colitis vs Crohn's disease) showed statistical significance only for men with Crohn's disease (odds ratio, 1.13; 95% confidence interval, 1.03-1.25; P = .009). At ages 6 months and older, cases and controls born from April through June received a significantly greater number of prescriptions for antibiotics than cases and controls born in other months. CONCLUSIONS: Men with Crohn's disease are more likely to have been born in the months of April through June.

High HIV risk in a cohort of male sex workers from Nairobi, Kenya.

OBJECTIVES: Men who have sex with men (MSM) are at high risk of HIV-1 acquisition and transmission, yet there remains limited data in the African context, and for men who sell sex to men (MSM SW) in particular. METHODS: We enrolled 507 male sex workers in a Nairobi-based prospective cohort study during 2009-2012. All participants were offered HIV/STI screening, counselling and completed a baseline questionnaire. RESULTS: Baseline HIV prevalence was 40.0% (95% CI 35.8% to 44.3%). Prevalent HIV infection was associated with age, less postsecondary education, marijuana use, fewer female partners and lower rates of prior HIV testing. Most participants (73%) reported at least two of insertive anal, receptive anal and insertive vaginal sex in the past 3 months. Vaginal sex was reported by 37% of participants, and exclusive MSM status was associated with higher HIV rates. Condom use was infrequent, with approximately one-third reporting 100% condom use during anal sex. HIV incidence was 10.9 per 100 person-years (95% CI 7.4 to 15.6). Predictors of HIV risk included history of urethral discharge (aHR 0.29, 95% CI 0.08 to 0.98, p=0.046), condom use during receptive anal sex (aHR 0.05, 95% CI 0.01 to 0.41, p=0.006) and frequency of sex with male partners (aHR 1.33/sex act, 95% CI 1.01 to 1.75, p=0.04). CONCLUSIONS: HIV prevalence and incidence were extremely high in Nairobi MSM SW; a combination of interventions including increasing condom use, pre-exposure prophylaxis and access to effective treatment is urgently needed to decrease HIV transmission in this key population.

Prevention of mother-to-child transmission of HIV in Kenya: challenges to implementation.

BACKGROUND: The prevention of mother-to-child transmission of human immunodeficiency virus (HIV) is lauded as one of the more successful HIV prevention measures. However, despite some gains in the prevention of mother-to-child transmission of HIV (PMTCT) in sub-Saharan Africa, mother-to-child transmission rates are still high. In Kenya, mother-to-child transmission is considered one of the greatest health challenges and scaling up PMTCT services is crucial to its elimination by 2015. However, guideline implementation faces barriers that challenge scale-up of services. The objective of this paper is to identify barriers to PMTCT implementation in the context of a randomized control trial on the use of structured mobile phone messages in PMTCT. METHODS: The preliminary analysis presented here is based on survey data collected during enrolment in PMTCT services at one of two health facilities in Nairobi, Kenya, with overall number of antenatal care (ANC) visits determined from 48 hour follow up data. RESULTS: Data was collected for 503 women. Despite significant differences in the type of facility and sample characteristics between sites, all women presented to care at 20 weeks gestation or later and 88.8% attended less than four ANC visits. PMTCT counselling at first visit had high coverage (86%), however less than a third of women (31.34%) reported receiving contraception counselling. Although 60.8% of women had reportedly disclosed their status to their partners, only 40% were aware of their partner's status. Very few women had been tested for TB (10%) or received single dose nevirapine during their first antenatal care appointment (20%). CONCLUSION: Revised PMTCT guidelines aim to reduce the inequity between PMTCT services in high and low resource settings in efforts to eliminate mother-to-child transmission. However, guideline implementation in low resource settings continues to be confronted with challenges related to late presentation, less than four ANC visits, low screening rates for opportunistic infections, and limited contraception counselling. These challenges are further complicated by lack of disclosure to partners. Effective scale up and implementation of PMTCT services requires that such ongoing program challenges be identified and appropriately addressed within the local context.

Stigmatization of Ebola virus disease survivors in 2022: A cross-sectional study of survivors in Sierra Leone.

BACKGROUND: Evidence has demonstrated a high proportion of Ebola virus disease (EVD) survivors experienced stigma due to the disease. This study sought to understand the longer-term effects of stigma encountered by survivors of the 2014-2016 EVD epidemic living in Sierra Leone. METHODS: This was a cross-sectional study of 595 EVD survivors and 403 close contacts (n = 998) from Sierra Leone. Assessments were conducted using a three-part survey between November 2021 to March 2022. We explored the socio-demographic factors associated with stigma experienced by EVD survivors. FINDINGS: 50·6 % (n = 301) of EVD survivors reported that they continued to experience at least one aspect of stigma. Females were disproportionately affected by stigma, with 45·2 % of females reporting isolation from friends and family compared to 33·9 % of men (p = 0·005). Multivariable logistic regression models revealed those aged 40-44, living rurally, and reporting an acute infection longer than seven days was associated with EVD-related stigma at the time of survey. INTERPRETATION: This study demonstrates stigma is still prevalent among people who survived EVD in 2022. It also identified socio-demographic factors associated with stigma that can be used for targeting interventions. Importantly, this highlights the continued need for EVD survivors to access mental healthcare and social support systems well after disease recovery. FUNDING: This study was funded by the Canadian Institutes for Health Research (Grant no. PJT-175098. JK is funded by a Tier 2 Canada Research Chair in the Molecular Pathogenesis of Emerging and Re-Emerging Viruses. SS is funded by a Tier 2 Canada Research Chair in Program Science and Global Public Health.

Research on the barriers to accessing sexual healthcare for sexually diverse Muslim men: protocol for a scoping review.

INTRODUCTION: Sexually diverse Muslim men are seen to be at a higher risk for HIV and other sexually transmitted infections due to their limited access to sexual healthcare services. We outline a protocol to conduct a scoping review of research on the barriers that may impede these men's access to sexual healthcare. METHODS AND ANALYSIS: To conduct this scoping review, we will follow the methodological framework developed by Arksey and O'Malley and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses' extension for scoping reviews. To classify the barriers to sexual healthcare, we will employ Bronfenbrenner's socioecological model as a conceptual framework. We will conduct a literature search via Medline, Embase and Global Health (OVID); Scopus; CINAHL on EBSCOhost along with several other EBSCOhost databases (Academic Search Complete, Canadian Reference Centre, Alternative Press Index, Family & Society Studies Worldwide, Social Work Abstracts) and Google Scholar, published until November 2023. Journal articles, published in the English language, describing quantitative and qualitative research on sexual healthcare access barriers for sexually diverse Muslim men will be included in the review. Commentaries and correspondences, along with grey literature including research reports and conference abstracts, as well as studies that do not include men with the Muslim faith, will be considered ineligible. Following screening of titles and abstracts, we will conduct a full-text screening to determine the final number of studies to be included in the review. A Microsoft Excel spreadsheet will be used to extract study characteristics, and information on sexual healthcare access barriers will be classified according to the socioecological model's core concepts. ETHICS AND DISSEMINATION: Our review does not require ethics approval. We will disseminate the review findings through peer-reviewed academic journals, seminars and conference presentations.

Clinical health outcomes of Ebola virus disease survivors eight years post recovery: a cross-sectional study in Sierra Leone.

Background: The West African Ebola virus disease (EVD) epidemic that occurred between 2013-2016 resulted in >28,000 confirmed cases and >11,000 fatalities. Thousands of survivors necessitate an understanding of the long-term health effects and future medical needs of these patients. Methods: A cross-sectional study of 595 EVD survivors from Sierra Leone and 403 close contacts (n=998). An in-person survey conducted between November 2021 and March 2022 included demographics, clinical health symptomology assessment of each organ system and a reproductive health assessment including sexual dysfunction question sets. The frequency of each disorder was examined and the association of each disorder with EVD survival was assessed. Results: Of 12 number of symptom types, five were reported by >50% of EVD survivors (Ocular, Neurological, Constitutional, Genitourinary, Dermatological), and all but one were reported by >40% of EVD survivors. Symptom types associated with EVD survival included ENT symptoms (AOR: 8.75, 95% CI: 5.63 - 13.60, p < 0.001), ocular symptoms (AOR: 7.18, 95% CI: 5.02 - 10.25, p < 0.001), dermatological symptoms (AOR: 4.16, 95% CI: 3.06 - 5.65, p < 0.001) and cardiovascular symptoms (AOR: 2.96, 95% CI: 2.12 - 4.13, p < 0.001). Conclusion: The West Africa EVD epidemic resulted in a high prevalence of persistent health issues among disease survivors. Continued support for survivor services in West Africa is crucial, and future outbreak response planning should include dedicated funding to ensure adequate care for survivors, both during the acute phase of infection and throughout the post recovery period.

A Population-Based Study of SARS-CoV-2 IgG Antibody Responses to Vaccination in Manitoba.

Understanding variables that influence antibody responses to COVID-19 vaccination within a population can provide valuable information on future vaccination strategies. In this population-based study, we examined the antibody responses to COVID-19 vaccination in Manitoba using residual serum specimens collected between January 2021 and March 2022 (n = 20,365). Samples were tested for spike and nucleocapsid IgG against SARS-CoV-2 using clinically validated assays. We assessed the impacts of multiple factors on post-vaccination antibody titres including type of vaccine, age, sex, geographic location, number of doses received, and timing of vaccination. Our investigation demonstrated that vaccination with one dose of Moderna mRNA-1273 elicited higher anti-spike IgG titres overall compared to Pfizer BNT162b2 vaccination, while one dose of Pfizer BNT162b2 followed by a second dose of Moderna mRNA-1273 exhibited higher titres than two doses of Pfizer BNT162b2 or Moderna mRNA-1273, irrespective of age. Age and time post-vaccination had considerable effects on antibody responses, with older age groups exhibiting lower anti-spike IgG titres than younger ages, and titres of those vaccinated with Pfizer BNT162b2 waning faster than those vaccinated with Moderna mRNA-1273 or a combination of Pfizer BNT162b2 and Moderna mRNA-1273. Antibody titres did not appear to be affected by sex or geographic location. Our results identify how factors such as age and type of vaccine can influence antibody responses to vaccination, and how antibody titres wane over time. This information highlights the importance of tailoring vaccine regimens to specific populations, especially those at increased risk of severe COVID-19 and can be used to inform future vaccination strategies, scheduling of booster doses, and public health measures.

Advancing Programme Science approaches to understand gaps in HIV prevention programme coverage for key populations in 12 Nigerian states: findings from the 2020 Integrated Biological and Behavioural Surveillance Survey.

INTRODUCTION: Effective HIV prevention programme coverage is necessary to achieve Nigeria's goal of ending the epidemic by 2030. Recent evidence highlights gaps in service coverage and utilization across the country. The Effective Programme Coverage framework is a Programme Science tool to optimize a programme's population-level impact by examining gaps in programme coverage using data generated through programme-embedded research and learning. We apply the framework using Integrated Biological and Behavioural Surveillance Survey (IBBSS) data from Nigeria to examine coverage of four prevention interventions-condoms, HIV testing, and needle and syringe programmes (NSP)-among four key population groups-female sex workers (FSW), men who have sex with men (MSM), people who inject drugs (PWID) and transgender people. METHODS: Data from Nigeria's 2020 IBBSS, implemented in 12 states, were analysed to examine HIV prevention programme coverage among key populations. For each key population group and prevention intervention of interest, weighted IBBSS data were used to retrospectively generate coverage cascades that identify and quantify coverage gaps. Required coverage targets were informed by targets articulated in Nigeria's National HIV/AIDS Strategic Framework or, in their absence, by guidelines from policy normative bodies. Availability-, outreach- and utilization coverage proxy indicators were defined using variables from IBBSS data collection tools. Sankey diagrams are presented to visualize pathways followed by participants between coverage cascade steps. RESULTS: Required coverage targets were missed for HIV testing and NSP among all key population groups. Condom availability coverage surpassed required coverage targets among FSW and MSM, while utilization coverage only among FSW exceeded the 90% required coverage target. Outreach coverage was low for all key population groups, falling below all required coverage targets. CONCLUSIONS: Our findings identify critical gaps in HIV prevention programme coverage for key populations in Nigeria and demonstrate non-linear movement across coverage cascades, signalling the need for innovative solutions to optimize coverage of prevention services. Programme-embedded research is required to better understand how key population groups in Nigeria access and use different HIV prevention services so that programmes, policies and resource allocation decisions can be optimized to achieve effective programme coverage and population-level impact.

Modelling vaccination approaches for mpox containment and mitigation in the Democratic Republic of the Congo.

BACKGROUND: Mpox was first identified in the Democratic Republic of the Congo (DRC) in 1970. In 2023, a historic outbreak of mpox occurred in the country, continuing into 2024. Over 14 000 cases and 600 deaths were reported in 2023 alone, representing a major increase from previous outbreaks. The modified vaccinia Ankara vaccine (brand names JYNNEOS, Imvamune, and Imvanex) was used in the 2022 mpox outbreak in the USA and Europe. However, at the time of the study, vaccination had not been made available in the DRC. We aimed to inform policy and decision makers on the potential benefits of, and resources needed, for mpox vaccination campaigns in the DRC by providing counterfactual scenarios evaluating the short-term effects of various vaccination strategies on mpox cases and deaths, if such a vaccination campaign had been undertaken before the 2023-24 outbreak. METHODS: A dynamic transmission model was used to simulate mpox transmission in the DRC, stratified by age (<5, 5-15, and >15 years) and province. The model was used to simulate potential vaccination strategies, varying by age and region (endemic provinces, non-endemic provinces with historic cases, and all provinces) assessing the effect the strategies would have on deaths and cases in an epidemic year similar to 2023. In addition, we estimated the number of vaccine doses needed to implement each strategy. FINDINGS: Without vaccination, our model predicted 14 700 cases and 700 deaths from mpox over 365 days. Vaccinating 80% of all children younger than 5 years in endemic regions led to a 27% overall reduction in cases and a 43% reduction in deaths, requiring 10·5 million vaccine doses. Vaccinating 80% of all children younger than 5 years in all regions led to a 29% reduction in cases and a 43% reduction in deaths, requiring 33·1 million doses. Vaccinating 80% of children aged 15 years or younger in endemic provinces led to a 54% reduction in cases and a 71% reduction in deaths, requiring 26·6 million doses. INTERPRETATION: When resources are limited, vaccinating children aged 15 years or younger, or younger than 5 years, in endemic regions of the DRC would be the most efficient use of vaccines. Further research is needed to explore long-term effects of a one-time or recurrent vaccination campaign. FUNDING: Canadian Institutes of Health Research, Canadian International Development Research Centre, US Department of Defense (Defense Threat Reduction Agency, Mpox Threat Reduction Network), Global Affairs Canada (Weapons Threat Reduction Program), US Department for Agriculture (Agriculture Research Service, Non-Assistance Cooperative Agreement).