Nationwide Implementation of HIV Molecular Cluster Detection by Centers for Disease Control and Prevention and State and Local Health Departments, United States

Abstract

Detecting and responding to clusters of rapid HIV transmission is a core HIV prevention strategy in the United States, guiding public health interventions and identifying gaps in prevention and care services. In 2016, the Centers for Disease Control and Prevention (CDC) initiated molecular cluster detection using data from 27 jurisdictions. During 2016-2023, CDC expanded sequence reporting nationwide and deployed Secure HIV-TRACE, an application supporting health department (HD) molecular cluster detection. CDC conducts molecular cluster detection quarterly; state and local HDs analyze local data monthly. HDs began routinely reporting clusters to CDC by using cluster report forms in 2020. During 2018-2023, CDC identified 404 molecular clusters of rapid HIV transmission; 325 (80%) involved multiple jurisdictions. During 2020-2023, HDs reported 298 molecular clusters to CDC; 249 were first detected by HDs. Expanding molecular cluster detection has provided a foundation for improving service delivery to networks experiencing rapid HIV transmission.

Keywords: HIV; HIV transmission; HIV/AIDS and other retroviruses; United States; molecular cluster; molecular epidemiology; outbreak detection; sexually transmitted infections; viruses.

Figure 1

Timeline of nationwide implementation of HIV cluster detection and response by CDC and state and local HDs in the United States. CDC, Centers for Disease Control and Prevention; HD, health department; Secure HIV-TRACE, Secure HIV TRAnsmission Cluster Engine.

Figure 2

Clusters of HIV newly reported to the Centers for Disease Control and Prevention by state and local health departments, United States, during 2020–2023. Clusters were reported to Centers for Disease Control and Prevention through cluster report forms. Methods by which clusters were first detected are indicated; nonmolecular cluster detection methods include time-space cluster detection, partner services, and provider notification. Numbers on top of bars indicate exact number of HIV clusters reported each year.

Figure 3

Region of reporting health department for clusters of HIV newly reported to the Centers for Disease Control and Prevention by state and local health departments, United States, during 2020–2023. Clusters were reported to Centers for Disease Control and Prevention through cluster report forms. Numbers and percentages of clusters are indicated for each region.