During the COVID-19 pandemic, men who have sex with men (MSM) in the USA have reported similar or fewer sexual partners and reduced HIV testing and care access compared with before the pandemic. Pre-exposure prophylaxis (PrEP) use has also declined. We aimed to quantify the potential effect of COVID-19 on HIV incidence and HIV-related mortality among US MSM. We used a calibrated, deterministic, compartmental HIV transmission model for MSM in Baltimore (MD, USA) and available data on COVID-19-related disruptions to HIV services to predict effects of reductions in sexual partners (0%, 25%, 50%), condom use (5%), HIV testing (20%), viral suppression (10%), PrEP initiations (72%), PrEP adherence (9%), and antiretroviral therapy (ART) initiations (50%). In our main analysis, we modelled disruptions due to COVID-19 starting Jan 1, 2020, and lasting 6 months. We estimated the median change in cumulative new HIV infections and HIV-related deaths among MSM over 1 and 5 years, compared with a base case scenario witrelated deaths (<1% change over 1 or 5 years). A 25% reduction in sexual partnerships is estimated to offset the effect of the combined service disruptions on new HIV infections (change over 1 year median -3·9% [-7·4 to 1·0]; over 5 years median 0·0% [-0·9 to 1·4]), but not on HIV deaths (change over 1 year 11·0% [6·2 to 17·7]; over 5 years 2·6% [1·5 to 4·3]). Maintaining access to ART and adherence support is of the utmost importance to maintain viral suppression and minimise excess HIV-related mortality due to COVID-19 restrictions in the USA, even if disruptions to services are accompanied by reductions in sexual partnerships. National Institutes of Health. National Institutes of Health.In 2010, the US health insurance system underwent one of its most substantial transformations with the passage of the Affordable Care Act, which increased coverage for millions of people in the USA, including those with and at risk of HIV. Even so, the system of HIV care and prevention services in the USA is a complex patchwork of payers, providers, and financing mechanisms. People with HIV are primarily covered by Medicaid, Medicare, private insurance, or a combination of these; many get care through other programmes, particularly the Ryan White HIV/AIDS Program, which serves as the nation's safety net for people with HIV who remain uninsured or underinsured but offers modest to no support for prevention services. While uninsurance has drastically declined over the past decade, the USA trails other high-income countries in key HIV-specific metrics, including rates of viral suppression. In this paper in the Series, we provide an overview of the coverage and financing landscape for HIV treatment and prevention in the USA, discuss how the Affordable Care Act has changed the domestic health-care system, examine the major programmes that provide coverage and services, and identify remaining challenges. The ChAdOx1 nCoV-19 (AZD1222) vaccine has been approved for emergency use by the UK regulatory authority, Medicines and Healthcare products Regulatory Agency, with a regimen of two standard doses given with an interval of 4-12 weeks. The planned roll-out in the UK will involve vaccinating people in high-risk categories with their first dose immediately, and delivering the second dose 12 weeks later. Here, we provide both a further prespecified pooled analysis of trials of ChAdOx1 nCoV-19 and exploratory analyses of the impact on immunogenicity and efficacy of extending the interval between priming and booster doses. In addition, we show the immunogenicity and protection afforded by the first dose, before a booster dose has been offered. We present data from three single-blind randomised controlled trials-one phase 1/2 study in the UK (COV001), one phase 2/3 study in the UK (COV002), and a phase 3 study in Brazil (COV003)-and one double-blind phase 1/2 study in South Africa (COV005). As previously describeHealth Research (NIHR), The Coalition for Epidemic Preparedness Innovations, the Bill & Melinda Gates Foundation, the Lemann Foundation, Rede D'Or, the Brava and Telles Foundation, NIHR Oxford Biomedical Research Centre, Thames Valley and South Midland's NIHR Clinical Research Network, and AstraZeneca. UK Research and Innovation, National Institutes of Health Research (NIHR), The Coalition for Epidemic Preparedness Innovations, the Bill & Melinda Gates Foundation, the Lemann Foundation, Rede D'Or, the Brava and Telles Foundation, NIHR Oxford Biomedical Research Centre, Thames Valley and South Midland's NIHR Clinical Research Network, and AstraZeneca.The HIV epidemic in the USA began as a bicoastal epidemic focused in large cities but, over nearly four decades, the epidemiology of HIV has changed. Public health surveillance data can inform an understanding of the evolution of the HIV epidemic in terms of the populations and geographical areas most affected. We analysed publicly available HIV surveillance data and census data to describe current HIV prevalence and new HIV diagnoses by region, race or ethnicity, and age; trends in HIV diagnoses over time by HIV acquisition risk and age; and the distribution of HIV prevalence by geographical area. We reviewed published literature to explore the reasons for the current distribution of HIV cases and important disparities in HIV prevalence. We identified opportunities to improve public health surveillance systems and uses of data for planning and monitoring public health responses. The current US HIV epidemic is marked by geographical concentration in the US South and profound disparities between regions and by race or ethnicity. https://www.selleckchem.com/products/mitosox-red.html Rural areas vary in HIV prevalence; rural areas in the South are more likely to have a high HIV prevalence than rural areas in other US Census regions. Ongoing disparities in HIV in the South are probably driven by the restricted expansion of Medicaid, health-care provider shortages, low health literacy, and HIV stigma. HIV diagnoses overall declined in 2009-18, but HIV diagnoses among individuals aged 25-34 years increased during the same period. HIV diagnoses decreased for all risk groups in 2009-18; among men who have sex with men (MSM), new diagnoses decreased overall and for White MSM, remained stable for Black MSM, and increased for Hispanic or Latino MSM. Surveillance data indicate profound and ongoing disparities in HIV cases, with disproportionate impact among people in the South, racial or ethnic minorities, and MSM.