For the new study, CDC researchers looked at RSV hospitalization rates across two different RSV surveillance networks of hospitals and medical centers (called RSV-NET and NVSN).
They compared the networks' hospitalization rates in the 20242025 RSV season to their respective rates in pre-pandemic seasons between 2018 and 2020.
The analysis found that among newborns (02 months), RSV hospitalizations fell 52 percent in RSV-NET and 45 percent in NVSN compared with the rates from the 20182020 period.
However, when the researcher excluded data from NVSN's surveillance site in Houstonwhere the 20242035 RSV season started before the vaccine and treatment were rolled outthere was a 71 percent decline in hospitalizations in NVSN.For a broader group of infants0 to 7 months oldRSV-NET showed a 43 percent drop in hospitalizations in the 20242025 RSV season, and NVSN saw a 28 percent drop.
Again, when Houston was excluded from the NVSN data, there was a 56 percent drop.Lastly, the researchers looked at hospitalization rates for toddlers and children up to 5 years old, who wouldn't have been protected by the new products.
There, they saw RSV hospitalization rates were actually higher in the 20242025 season than in the pre-pandemic years.
That suggests that the latest RSV season was more severe, and the drops in infant hospitalizations may be underestimates.