RSV Season Returns to Normal
After two years of heightened alerts, the U.S. Centers for Disease Control and Prevention (CDC) says the timing of seasonal respiratory syncytial virus (RSV) cases was disrupted during the COVID-19 pandemic.
The CDC's Morbidity and Mortality Weekly Report, published on April 7, 2023, stated RSV circulation was historically low during 2020–21.
And began earlier and continued longer during 2021–22 than previous RSV seasons.
And the 2022–23 RSV season started later than 2021–22, suggesting a return toward prepandemic seasonality.
During the prepandemic period (2017–2020), RSV cases began in early July (epidemiologic week 27) and ended the following year in June (week 26).
The CDC says that although an eventual return to prepandemic RSV seasonality was expected, clinicians should be aware that off-season RSV circulation might continue from October to April this year.
Furthermore, this CDC report confirmed RSV season generally starts in Florida.
In both prepandemic and pandemic periods, RSV cases began earlier in Florida and the Southeast and later in other regions.
During the Florida prepandemic RSV seasons, the median onset occurred in August, and the peak occurred in November and continued until March (median duration = 30 weeks).
The consistency of this pattern could help predict the timing of future epidemics in specific regions, wrote the CDC.
This information indicates healthcare providers located in Florida should be prepared to treat RSV patients during the early summer.
In the United States, RSV infections cause an estimated 58,000–80,000 hospitalizations among young children and 60,000–160,000 hospitalizations among seniors annually.
Since the U.S. Food and Drug Administration has yet to authorize any RSV vaccine candidates currently in late-stage clinical trials, Florida could have increased access to injectable monoclonal antibody (mAbs) therapy.
Initially authorized in 1998, first-generation mAbs have been selectivity offered in the U.S.
Synagis® (Palivizumab) is a multi-dose injectable RSV antibody limited to high-risk infants and provides one-month protection, requiring five injections to cover an RSV season.
However, a newer version is approaching authorization in the U.S.
The CDC's Advisory Committee on Immunization Practices meeting on February 23, 2023, reviewed nirsevimab.
AstraZeneca and Sanofi co-developed Beyfortus® (Nirsevimab), a single-dose, long-acting mAbs designed to protect infants through their first RSV season.
Last RSV season, the European Commission granted Beyfortus worldwide approval on November 4, 2022.