September 25, 2025

RSV

Clesrovimab for Prevention of RSV Disease in Healthy Infants
A total of 3,614 infants received an injection: 2,412 infants received clesrovimab, and 1,202 infants received placebo. Through day 150 after injection, RSV-associated medically attended lower respiratory infection occurred in 60 of 2,398 infants in the clesrovimab group (incidence rate over five-month period, 2.6%) and in 74 of 1201 infants in the placebo group (incidence rate over five-month period, 6.5%), for an efficacy of 60.4% (95% confidence interval [CI], 44.1 to 71.9; P<0.001). RSV-associated hospitalization within 150 days was reported in nine of 2,398 infants in the clesrovimab group and in 28 of 1,201 infants in the placebo group, for an efficacy of 84.2% (95% CI, 66.6 to 92.6; P<0.001). Serious adverse events were reported in 278 of 2,409 infants (11.5%) in the clesrovimab group and 149 of 1,202 infants (12.4%) in the placebo group.

Screwworm

Mexico Boosts Controls on Cattle after New Screwworm Case Found Near U.S. Border in Nuevo Leon
Mexico activated emergency controls Monday after detecting a new case of New World screwworm in cattle in the northern border state of Nuevo Leon state, the closest case to the U.S. border since the outbreak began last year. The animal, found in the town of Sabinas Hidalgo, came from the Gulf state of Veracruz, Mexico’s National Health for Food Safety and Food Quality Service said. The last case was reported July 9 in Veracruz, prompting Washington to suspend imports of live Mexican cattle.

Measles

More Measles Cases Now in 2025 Than Any Year Since It Was Declared Eliminated in 2000
As of September 23, 2025, there have been a total of 1,514 confirmed measles cases reported in the United States.

Influenza

Influenza-Associated Pediatric Deaths — United States, 2024–25 Influenza Season
The 2024–25 influenza season had the highest number of pediatric deaths reported (280) since child deaths became nationally notifiable in 2004, except for the 2009–10 influenza A(H1N1)pdm09 pandemic. Approximately one half of children who died from influenza had an underlying medical condition, and 89% were not fully vaccinated.’ The median age at death was 7 years and 40% of children who died were treated with influenza antiviral medications.