CDC approves Merck's RSV vaccine for infants despite concerns

In June 2025, experts from the US Centers for Disease Control and Prevention met to discuss the approval of a new shot aimed at protecting infants from respiratory syncytial virus (RSV). The meeting concluded with a 5-2 vote by the Advisory Committee on Immunization Practices (ACIP) supporting the use of Merck’s Enflonsia vaccine, the product of rigorous clinical trials demonstrating safety and efficacy. This vaccine will especially target infants under 8 months who experience their first exposure to RSV, which affects many children under two years old, leading to hospitalization and serious illness. CDC officials highlighted the new vaccine's importance in preventing RSV-related health issues among infants, who are most vulnerable to severe infection. With approximately 58,000 hospitalizations of young children attributed to RSV each year in the United States, the need for effective preventative measures is critical. Previously, there were alternative interventions available, including an antibody shot and a vaccine for pregnant women. However, the emergence of Enflonsia is viewed as a significant advancement in providing additional protection. Opposition and concern were voiced, particularly from two committee members, about the potential safety signals from clinical trials and the newly constituted committee's approach to vaccine approval, which had seen previous panelists dismissed due to alleged conflicts of interest. This vote marks a pivotal moment not just for the prevention of RSV but also for public health policy concerning vaccines in general. The final review by the CDC director is anticipated, as the committee takes its recommendation forward into practice, emphasizing that free access to this vaccine will be provided through the Vaccines for Children Program, ultimately benefitting families in need.