BACKGROUND: Clusters of rapid HIV transmission indicate larger underlying networks that are not effectively reached by HIV prevention, testing, and care services. Starting in 2018, the Centers for Disease Control and Prevention (CDC) funded 59 U.S. health departments (HDs) to detect and respond to HIV clusters; HDs began reporting clusters to CDC in January 2020. METHODS: For clusters reported to CDC, we described cluster characteristics at detection, including detection method; size; HIV transmission category, defined as that of >50% of cluster members; and HD investigation and response activities. RESULTS: During 2020-2022, 45 HDs reported 322 HIV clusters, with most detected by molecular analysis of HIV sequences (75%). Most were detected in the South (46%) and three-quarters were predominant sexual transmission. Median cluster size at detection for molecular clusters was 10 persons (interquartile range 7-18). Among 205 clusters with follow-up data, investigation and response activities were conducted for 95%, including direct outreach to persons in clusters for partner services (64%), medical chart reviews (42%), and focused testing events (13%). Limited data on named partners tested showed that 11% received new HIV diagnoses. CONCLUSIONS: HD HIV cluster detection activities detected many clusters. Response activities were tailored for different clusters and intervened in networks with rapid transmission and high undiagnosed infection, as indicated by high positivity among partners. Cluster detection and response is an important tool to identify and address gaps in HIV prevention, testing, and care that facilitate rapid transmission.

High prevalences of HIV and other sexually transmitted infections (STIs) have been reported in the current global monkeypox outbreak, which has affected primarily gay, bisexual, and other men who have sex with men (MSM) (1-5). In previous monkeypox outbreaks in Nigeria, concurrent HIV infection was associated with poor monkeypox clinical outcomes (6,7). Monkeypox, HIV, and STI surveillance data from eight U.S. jurisdictions* were matched and analyzed to examine HIV and STI diagnoses among persons with monkeypox and assess differences in monkeypox clinical features according to HIV infection status. Among 1,969 persons with monkeypox during May 17-July 22, 2022, HIV prevalence was 38%, and 41% had received a diagnosis of one or more other reportable STIs in the preceding year. Among persons with monkeypox and diagnosed HIV infection, 94% had received HIV care in the preceding year, and 82% had an HIV viral load of <200 copies/mL, indicating HIV viral suppression. Compared with persons without HIV infection, a higher proportion of persons with HIV infection were hospitalized (8% versus 3%). Persons with HIV infection or STIs are disproportionately represented among persons with monkeypox. It is important that public health officials leverage systems for delivering HIV and STI care and prevention to reduce monkeypox incidence in this population. Consideration should be given to prioritizing persons with HIV infection and STIs for vaccination against monkeypox. HIV and STI screening and other recommended preventive care should be routinely offered to persons evaluated for monkeypox, with linkage to HIV care or HIV preexposure prophylaxis (PrEP) as appropriate.

During October 2019, the West Virginia Bureau for Public Health (WVBPH) noted that an increasing number of persons who inject drugs (PWID) in Kanawha County received a diagnosis of HIV. The number of HIV diagnoses among PWID increased from less than five annually during 2016-2018 to 11 during January-October 2019 (Figure). Kanawha County (with an approximate population of 180,000*) has high rates of opioid use disorder and overdose deaths, which have been increasing since 2016,(†) and the county is located near Cabell County, which experienced an HIV outbreak among PWID during 2018-2019 (1,2). In response to the increase in HIV diagnoses among PWID in 2019, WVBPH released a Health Advisory(§); and WVBPH and Kanawha-Charleston Health Department (KCHD) convened an HIV task force, conducted care coordination meetings, received CDC remote assistance to support response activities, and expanded HIV testing and outreach.