TOPLINE:

Maternal influenza and tetanus-diphtheria-acellular pertussis (Tdap) vaccination during pregnancy was associated with substantial reductions in influenza- and pertussis-related hospitalizations and emergency department (ED) visits in infants younger than 6 months.

METHODOLOGY:

• Researchers conducted a population-based cohort study to assess whether maternal influenza and Tdap vaccinations during pregnancy are associated with reduced influenza- and pertussis-related hospitalizations and ED visits in infants younger than 6 months.
• They included 53,448 pregnant women who received the Tdap vaccine and 5347 who received the influenza vaccine; each vaccinated mother-infant dyad was matched with an unvaccinated dyad based on delivery timing, gestational age at birth, and pregnancy multiplicity.
• The primary outcome was a composite endpoint of infant hospital admissions or ED visits for influenza or pertussis within 6 months after birth.
• Infants were followed up from birth until the earliest of 6 months of age, the occurrence of the clinical outcome, emigration, death, or the end of the study period; in the Tdap cohort, the follow-up period was additionally censored at the infant’s pertussis vaccination date.

TAKEAWAY:

• Maternal influenza vaccination during pregnancy was associated with a 70% lower risk for an infant influenza-related hospitalization or ED visit (vaccine effectiveness, 69.7%; 95% CI, 8.7%-90.0%; hazard ratio [HR], 0.30; 95% CI, 0.10-0.91).
• Similarly, maternal Tdap vaccination during pregnancy was associated with an 89% lower risk for an infant pertussis-related hospitalization or ED visit (vaccine effectiveness, 88.6%; 95% CI, 11.5%-98.5%; HR, 0.11; 95% CI, 0.02-0.88).
• Vaccination coverage remained suboptimal, at 6.4% for influenza and 41.0% for Tdap among eligible pregnant individuals.

IN PRACTICE:

“These results support the current recommendations for administering these vaccines during pregnancy and highlight the urgent need to implement strategies aimed to increase their acceptance,” the authors wrote.

SOURCE:

This study was led by Gabriella Morabito, MSc, National Centre for Healthcare Research and Pharmacoepidemiology, University of Milano-Bicocca, Milan, Italy. It was published online on January 08, 2026, in JAMA Network Open.

LIMITATIONS:

This study was limited to National Health Service records and excluded vaccinations administered in private practice. The accuracy of hospital diagnoses was not verified, which could have led to outcome misclassification. A limited sample size constrained subgroup analyses by gestational age and vaccine timing during pregnancy.

DISCLOSURES:

This study was supported by PNRR 2022-NAZ-0524 — PRIN 2022 under the National Recovery and Resilience Plan. One author disclosed receiving research support from the European Community, the Italian Agency of Drug, and the Italian Ministry of Education, University and Research and participating in projects funded by Novartis, GSK, Roche, AMGEN, BMS, and Servier.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.