RSV Season Begins to Spike

While the World Health Organization (WHO) Influenza Update N° 456 says respiratory syncytial virus (RSV) activity was generally low or decreasing globally, new data indicates the United States is seeing measurable increases.

The U.S. Centers for Disease Control and Prevention (CDC) RSV detection graphs showed increases throughout the U.S. as of October 27, 2023.

The National Respiratory and Enteric Virus Surveillance System (NREVSS) reports that the weekly percentage of RSV polymerase chain reaction (PCR) test positivity was 10.9% as of October 21, 2023.

During the 2022–2023 RSV season, positive test results peaked in November.

From an age perspective, the Weekly Emergency Department Visits chart clearly indicates that the most affected by this RSV season have been children under one-year-old.

In 2022, the JAMA Network conducted an Original Investigation that found 96 (95% CI, 92-99) RSV deaths among children younger than one year. And a study published by the Journal of Infectious Diseases determined that RSV-related deaths in infants <1 year peaked at about one month.

Furthermore, a meta-analysis of eleven studies published in October 2023 found that the meta-estimate of RSV-positive tests among pregnant women was  3.4%  (95% CI: 1.9; 54).

According to the CDC, RSV has geographic trends in the U.S.

Florida's RSV season is longer than the rest of the country and has distinct regional patterns.

The Florida Department of Health reported as of week #42, October 21, 2023, RSV activity was increasing in hospital admissions and emergency room rates, with current outbreaks in Martin (1), Pinellas (2), and Volusia (1). 

Fortunately, for the first time, there are approved RSV vaccines and passive immunizations available in the U.S. this season.