A new study suggests that a maternal vaccine and a monoclonal antibody may have contributed to last winter’s milder RSV season for U.S. babies. The 2024-25 season was the first time these preventive tools were widely available, and data from two hospital surveillance systems show a significant decrease in RSV hospitalization rates among infants up to 7 months old.
RSV is a major cause of infant hospitalizations, particularly in young children. The virus is difficult for infants to fight due to their immature airways and lack of pre-existing immunity. This can lead to severe lung infections, such as bronchiolitis.
The new study analyzed data from two surveillance systems that track RSV-associated hospitalizations. The results show a 43% decrease in RSV hospitalization rates among infants up to 7 months old compared to the two previous seasons before the COVID-19 pandemic. This drop was even more pronounced for the youngest infants, with hospitalization rates falling by 52% and 45% for those up to 2 months old.
The U.S. Centers for Disease Control and Prevention recommends using one of these preventive tools: a maternal vaccine given to pregnant people during a specific window in the last trimester, or a monoclonal antibody called nirsevimab that can be given to babies born during RSV season. Both of these tools target a protein on the virus that it needs to enter cells.
Experts are optimistic about the impact of these preventive tools and predict that RSV hospitalizations in young infants will become much rarer in the future. The availability of these products is also crucial for vulnerable children in countries with limited access to healthcare, where most RSV-related deaths occur.
Source: https://www.sciencenews.org/article/rsv-babies-virus-vaccine-antibodies