A large population-based cohort study recently provided further evidence that administering influenza and pertussis vaccines on the same day is safe during pregnancy.1
Investigators analyzed data from 13,918 singleton pregnancies in New South Wales, Australia, comparing women who received concomitant influenza and pertussis vaccination at ≥20 weeks’ gestation with matched controls who received pertussis vaccination alone. The matching accounted for maternal age, gestation at vaccination, and calendar timing of vaccination.
The study leveraged linked perinatal, immunization, and hospitalization data sets, allowing for assessment of clinically meaningful outcomes, including preterm birth, small for gestational age (SGA), low birth weight, stillbirth, and several maternal complications.
“A health care provider recommendation is one of the most important factors people consider when making decisions about vaccination,” said lead author Nicole Sonneveld, MSc (Med), Senior Research Officer, National Center for Immunization Research and Surveillance, Westmead, New South Wales. “We hope that these findings, together with the reassuring findings from earlier studies that assessed the safety of concomitant vaccination in pregnancy, help health care providers to be more confident in giving the influenza and pertussis vaccines at the same time, where appropriate.”
Across primary outcomes, concomitant vaccination was not associated with an increased risk of adverse pregnancy or neonatal outcomes. Specifically:
- Preterm birth occurred in 3.8% of the concomitant group vs 4.4% of controls.
- Rates of SGA were 8.8% vs 9.9%, respectively.
- Low birth weight occurred in 1.7% vs 1.6%, respectively.
Adjusted analyses showed no statistically significant differences for preterm birth (adjusted HR .83; 95% CI, .66-1.05), SGA (adjusted OR 0.87; 95% CI, .74-1.04), or low birth weight (adjusted OR .94; 95% CI, .66-1.35).
Secondary outcomes—including antepartum hemorrhage, preeclampsia or eclampsia, prelabor rupture of membranes, preterm labor, and postpartum hemorrhage—also showed no significant differences between groups. Importantly, the investigators found no safety signals for neonatal outcomes such as low Apgar scores, which were identical (1.2%) across groups.
“Given the limited duration of pregnancy, coadministration helps maximize uptake across the multiple recommended vaccines,” said Viren Kaul, MD, FCCP, Chief of the Department of Medicine at Crouse Health, Syracuse, New York. “Influenza vaccination lagged pertussis vaccination in this Australian cohort, possibly because each separate visit is a point of attrition. Removing the ‘come back another day’ barrier lets us capture the flu dose at the same encounter as [tetanus, diphtheria, and pertussis]. In practical terms, every visit that bundles rather than defers care is a recovered opportunity for vaccines that reduce maternal hospitalization and confer neonatal protection.”
Stephanie M. Levine, MD, Master FCCP, Professor of Medicine at UT Health San Antonio, Texas, said the study provides an important foundation for future maternal vaccine programs.
“As [respiratory syncytial virus] and other maternal vaccines become more widely used, these data support the concept that administering recommended vaccines during the same visit may be both safe and practical, although additional studies evaluating specific vaccine combinations will remain important,” she said.
In counseling patients who are hesitant about receiving multiple vaccines at once, Sonneveld said that clinicians can now point to multiple studies that do not show any safety concerns regarding same-day influenza and pertussis vaccination.
“We have active surveillance studies suggesting no increased rate of fever or required medical attention for the pregnant person themselves in the few days immediately following same-day vaccination compared with receiving the vaccines individually,” Sonneveld said. “This adds to the evidence that there is also no increased rate of important pregnancy, birth, and neonatal outcomes with same-day influenza and pertussis vaccination compared with receiving the pertussis vaccine by itself.”
References
1. Sonneveld N, Reekie J, Deng L, O’Grady KA, Macartney K, Liu B. Coadministered influenza- and pertussis-containing vaccines in pregnant women. JAMA Netw Open. 2026;9(4):e267551. doi:10.1001/jamanetworkopen.2026.7551
