Infant Protection Against Respiratory Syncytial Virus (RSV) by Maternal RSV Vaccination or Receipt of Nirsevimab, and Intent for Nirsevimab Receipt, United States

At a glance

Monthly estimates of infant protection against RSV by maternal RSV vaccination or receipt of nirsevimab, as well as intent for nirsevimab receipt, reported by adult females aged 18-49 years are from the National Immunization Survey─Adult COVID Module (NIS─ACM).

Nirsevimab Receipt and Intent for Infants

Monthly estimates of infant protection against RSV by maternal RSV vaccination or receipt of nirsevimab, as well as intent for nirsevimab receipt, were calculated using data from the National Immunization Survey–Adult COVID Module (NIS–ACM). Data were reported by adult females aged 18–49 years with infants under the age of 8 months during the RSV season (born since April 1, 2024). The NIS–ACM is an ongoing random-digit-dial cellular telephone survey of households with adults 18 years and older. All estimates are based upon parent-reported receipt of nirsevimab.

  • Figure 6. Infant Protection Against RSV by Maternal RSV Vaccination* or Receipt of Nirsevimab, and Intent for Nirservimab Receipt, Reported By Females Aged 18–49 Years Who Have an Infant <8 Months During the RSV Season (born since April 1, 2024), by Month of Interview, United States§. Data Source: National Immunization Survey–Adult COVID Module.

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Note: August 2024 estimates are based on data collected from August 18 through August 31, 2024. For data collected August 18 through September 30, 2024, only intent estimates are available. Parent-reported receipt of nirsevimab by infants was collected starting October 1, 2024.

Confidence Intervals (CIs) describe the level of uncertainty around an estimate because a sample was taken. 95% CIs represent the range of values that would result if the data collection had been repeated many times. For a 95% confidence interval, if the sampling method is repeated many times, the true value would fall within this interval at least 95% of the time. Wider CIs reflect larger random error in estimates resulting from survey sampling.

Estimates from the NIS–ACM may differ from estimates based on other data sources, and in addition to random error associated with taking a sample, are subject to errors resulting from incomplete sample frame (exclusion of households without cell phones), selection bias (survey respondents may be more likely to be vaccinated than non-respondents), and errors in self-reported vaccination status. Estimates are weighted to selected sociodemographic characteristics of the U.S. population to reduce possible bias from incomplete sample frame and selection bias.

*Receipt of RSV vaccination during pregnancy was assessed by the NIS–ACM questionnaire among females 18–49 years who reported having an infant born since October 1, 2024. For infants born April 1, 2024, through September 30, 2024, maternal RSV vaccination was not assessed, and these infants were assumed to be protected against RSV only if infant was reported to have received nirsevimab. The estimates of receipt of RSV vaccination during pregnancy for infants born since April 1, 2024 are not an assessment of maternal RSV vaccination coverage among pregnant persons eligible for vaccination as shown with the Vaccine Safety Datalink, as they are based on all infants eligible for nirsevimab or maternal vaccination rather than eligible pregnancies (https://www.cdc.gov/rsv/hcp/vaccine-clinical-guidance/pregnant-people.html).

†Estimates of nirsevimab receipt by infants born since April 1, 2024, include those who were born shortly before or are entering their first RSV season and do not account for the mother's RSV vaccination status during pregnancy (Healthcare Providers: RSV Immunization for Children 19 Months and Younger | CDC).

‡Intent for nirsevimab receipt is assessed among infants who had not received nirsevimab and whose mother did not receive RSV vaccination during pregnancy. Estimates of nirsevimab intent among women interviewed in August and September 2024 included all women who reported having an infant <8 months, and could include infants born in February and March 2024.

§National estimates include 50 states, Washington D.C., Guam, and Puerto Rico.

±Estimates are based on interviews conducted during Sunday through Saturday weeks assigned to the monthly analytic period, which may include some dates in the month before or after the specified analytic month. Unlike the weekly RSV vaccination coverage estimates, they are not cumulative estimates based on all interviews conducted to date.