Cases of respiratory syncytial virus (RSV) continue to be a cause for concern as the winter season approaches in the United States. According to the Centers for Disease Control and Prevention (CDC), RSV activity "remains elevated" across the country, with some areas experiencing decreases in cases. Hospitalization rates have also seen an increase, particularly among young children and older adults.

Last winter, the U.S. saw a significant increase in RSV cases, with many parents hearing about the illness for the first time. RSV, a common childhood illness that typically starts in the fall and peaks in the winter, often presents cold-like symptoms in kids, such as cough, runny nose, and fever, according to the American Academy of Pediatrics (AAP). In severe cases, children may develop bronchiolitis, with symptoms including rapid or difficult breathing.

A recent study published in the journal JAMA Network Open analyzed data from 600 infants across 39 hospitals in the U.S. who required intensive care for an RSV infection in 2022. The study found that most of these infants were delivered at full term and previously healthy. The highest risk of intubation was observed among children under 3 months old and those born prematurely.

While RSV can affect anyone, doctors emphasize that children born prematurely or with underlying health conditions are at the highest risk of developing serious complications from the virus. However, healthy individuals can also experience severe illness and may require hospitalization, according to Dr. Thomas Russo, a professor and chief of infectious diseases at the University at Buffalo.

To combat the spread and severity of RSV, new preventive measures have been introduced. In July, the Food and Drug Administration (FDA) approved a new RSV drug called Beyfortus (nirsevimab) for babies and children. Beyfortus provides long-acting antibodies through passive immunity, bypassing the need for the activation of the immune system. The CDC recommends one dose of Beyfortus for infants under 8 months old born during or entering their first RSV season, as well as for children between 8 and 19 months old at increased risk of severe RSV disease entering their second RSV season.

In August, the FDA also approved the first RSV vaccine for pregnant women. A study involving nearly 7,400 pregnant women found that the vaccine, named Abrysvo, was 82% effective at preventing lower respiratory tract disease caused by RSV during the first three months of their babies' lives. It remained 69% protective against severe complications at six months of age. The recommended timeframe for administering Abrysvo is between weeks 32 and 36 of pregnancy.

Looking ahead to the upcoming RSV season, medical professionals acknowledge uncertainty due to the unusual nature of the previous season. However, they still emphasize the importance of taking precautions to minimize the risk of severe RSV. Regular handwashing, staying home when unwell, and reducing newborns' contact with large groups, especially during cold and flu season, are recommended infection-control measures.

While the impact of the current RSV season remains to be seen, health officials urge vigilance and adherence to preventive measures. "We expected to see more viruses, we expected to see more COVID and flu and RSV, and that's exactly what we're seeing," says CDC director Mandy Cohen. The situation will continue to be closely monitored as health authorities work to mitigate the spread and severity of RSV in the population.