Study identifies gaps in infant RSV immunization timing

Despite recommendations aimed at protecting infants against respiratory syncytial virus (RSV), new real-world data suggest gaps remain in the timely administration of nirsevimab (Beyfortus), particularly among infants born during the RSV season. Findings presented at IDWeek 2026, held October 21 to 24 in Washington, DC, revealed that only 35.4% of infants born during the RSV season who received nirsevimab in participating outpatient clinics were immunized within 7 days of birth, the recommended window for this population. The median time to administration was 14 days, highlighting opportunities to improve early protection against RSV-associated lower respiratory tract infection.

The retrospective cohort study evaluated 80,862 infants born between April 2025 and March 2026 across a national network of pediatric and family medicine primary care clinics, with 17,771 infants receiving nirsevimab through the participating outpatient network. Among 10,646 recipients born outside the RSV season, 78.4% received nirsevimab within the first 2 months of the season's start, while 21.6% received it later. Researchers also identified disparities by insurance status, with self-pay infants born during the RSV season experiencing a median 27-day delay from birth to administration, compared with 14 days among commercially insured infants and 13 days among those covered by Vaccines for Children (VFC)/Medicaid. Infants who received nirsevimab also demonstrated greater engagement with primary care and higher uptake of routine childhood immunizations. However, because the analysis did not capture inpatient or other immunization settings, the findings cannot establish overall nirsevimab coverage.

To discuss the clinical implications of these findings, Contemporary Pediatrics spoke with Ayman Chit, Head of North America Medical, Vaccines at Sanofi, about barriers to timely nirsevimab administration, opportunities to address disparities in RSV prevention, and strategies pediatricians can implement to improve immunization timing. The conversation also explores how proactive scheduling, caregiver education, and targeted outreach may help close gaps in protection for infants entering their first RSV season.

Contemporary Pediatrics: Your study found that only 35.4% of infants born during RSV season received nirsevimab within the recommended 7-day window, with a median administration time of 14 days. What do you believe are the primary barriers to timely administration, and what can pediatricians do to address these gaps?

Ayman Chit, PhD: The study was designed to assess real-world patterns of nirsevimab administration and identified gaps in timely administration. Awareness of the gap is the first step in addressing it. Some practical opportunities for pediatric care teams: proactive education of staff on recommendations and policies, a reminder system for 3-5 day well-baby appointment adherence for infants born during RSV season, and confirming whether an infant is due for RSV immunization before their first newborn appointment all may help improve timely administration.

Contemporary Pediatrics: Among infants born outside RSV season, 21.6% received nirsevimab more than 2 months after the season began. What opportunities exist for pediatric practices to improve early-season administration, and how might proactive scheduling or reminder systems help ensure infants receive protection before RSV exposure?

Chit: This study found that 21.6% of out-of-season births received protection more than 2 months into RSV season. This demonstrates a key opportunity for improvement. Educating families of out-of-season-born infants before the RSV season begins can help prepare them for getting immunized early in the RSV season. Additionally, education of staff and recall and reminder systems can ensure that appointments are in place shortly before or at the beginning of the RSV season. These efforts may help more infants receive protection ahead of potential RSV exposure during the season.

Contemporary Pediatrics: The study identified notable differences in administration timing by insurance status, with self-pay infants receiving nirsevimab later than those with commercial insurance or Medicaid coverage. What factors may be contributing to these disparities, and what strategies could pediatric practices implement to improve equitable access?

Chit: It is always unfortunate to observe healthcare access disparities, but it is important to acknowledge that they exist in order to address them. In this study, Vaccines for Children/Medicaid-eligible infants had a similar median time to administration as the commercially insured infants. The access challenge in this study was unique to self-paying families, primarily related to insurance rostering. When infants attend a medical home in their first couple weeks of life, and the parent has commercial insurance, but the baby is not yet rostered under their parent’s insurance, many medical homes will bill as “self-pay.” When this occurs in practice, the clinic or parent takes the risk of immunization payment on themselves while waiting for their infant to be added to their insurance plan. Solving this issue to optimize equitable access requires faster rostering processes at the payer level.

Contemporary Pediatrics: Infants who received nirsevimab also had higher rates of routine childhood vaccination and more frequent primary care visits than those who did not. What do these findings suggest about the relationship between nirsevimab uptake and broader engagement with pediatric preventive care, and how can clinicians identify infants at risk of missing recommended immunizations?

Chit: Infants who are adhering to routine recommendations, including receipt of nirsevimab and attending well-baby visits, are more likely to get vaccinated with other childhood vaccines. This may be due to a combination of overall health-seeking behaviors, access to routine care, and parental hesitancy. Providers can prepare parents early and educate them on the RSV immunization during prenatal consultations. Once the baby is under their care, providers can implement reminder systems and take action to reach out when they see early warning signs like missed appointments to help ensure their infant can be protected against serious RSV lung infection. Research in this area would help better characterize the gap and develop better evidence-based solutions.

Contemporary Pediatrics: Given that your analysis was limited to outpatient administration and did not capture nirsevimab received in birth hospitals or other care settings, how should pediatricians interpret these findings? What additional research is needed to better understand overall immunization coverage and identify the most effective interventions to improve timely protection against RSV?

Chit: The analysis included 17,771 infants in a national network of pediatric and family medicine primary care clinics serviced by VaxCare who received nirsevimab. The findings of this study should be viewed as an analysis of outpatient administration timing, not as an estimate of nirsevimab coverage. More research is needed to explore RSV immunization coverage and trends considering maternal RSV vaccination and infant RSV immunization across healthcare settings. Additionally, research is needed on what interventions (e.g., proactive education, reminders, earlier scheduling, equity-focused outreach, and systematic catch-up) have a positive impact on timely administration rates. Ultimately, the goal is to protect all infants, all season, ensuring that all infants in every setting can receive protection within the recommended time frames.

Reference

Lang K, Graterol A, Bergren N, et al. Timing and uptake of nirsevimab among infants born during and outside of the RSV season in a large US pediatric primary care cohort: recommendation adherence, demographic trends, and targeted catch-up opportunities. Poster presented at: IDWeek 2026; October 21-24, 2026; Washington, DC. Abstract P-1161.