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A new population based cohort study published in JAMA Network Open on January 8, 2026 reports that getting influenza and tetanus diphtheria acellular pertussis (Tdap) vaccines during pregnancy is linked to a substantially lower risk of hospital or emergency department visits for influenza and pertussis among infants younger than six months. The researchers estimated vaccine effectiveness of 69.7 percent for maternal influenza vaccination against infant influenza related hospital and ER visits and 88.6 percent for maternal Tdap vaccination against infant pertussis related hospital and ER visits. [jamanetwork.com]
These findings add real world evidence to long standing guidance from public health and obstetric organizations that recommend influenza and Tdap vaccination during pregnancy to protect both the mother and her newborn. [cdc.gov], [acog.org]
The investigation examined health care utilization data from Lombardy, Italy and included large matched cohorts of mother infant pairs. For the influenza cohort there were 84,348 dyads, and for the Tdap cohort there were 171,141 dyads, covering births from 2018 to 2022. Infants were followed to six months of age, and the outcomes measured were hospitalizations or ER visits with diagnoses of influenza or pertussis. Using Cox regression and calculating vaccine effectiveness from adjusted hazard ratios, the authors estimated 69.7 percent effectiveness for maternal influenza vaccination and 88.6 percent effectiveness for maternal Tdap vaccination. [jamanetwork.com]
The study also documented suboptimal maternal vaccine uptake in Italy, with 6.4 percent coverage for influenza and 41.0 percent for Tdap among pregnant individuals. This gap underscores the need for stronger communication and access strategies so that more families benefit from these protections. [medicalxpress.com], [cidrap.umn.edu]
Importantly, infants younger than six months are too young to receive the seasonal flu vaccine, and infants younger than two months do not receive Tdap. Maternal immunization helps bridge that early vulnerability by passing protective antibodies through the placenta before birth. [cidrap.umn.edu], [cdc.gov]
Influenza can cause severe respiratory illness in pregnant people and newborns, increasing risks of hospitalization and complications. Because newborns cannot be vaccinated against influenza until six months, the mother’s vaccination during pregnancy provides passive antibodies for early protection. ACOG advises that people who are or will be pregnant during the season should receive inactivated or recombinant influenza vaccine in any trimester as soon as vaccine is available. [acog.org], [guidelinecentral.com]
Pertussis or whooping cough is particularly dangerous for babies in the first months of life. Episodes can lead to apnea, pneumonia and in severe cases death. The CDC and the NHS recommend Tdap during pregnancy so the mother’s antibodies protect the baby until routine infant doses begin. In the United States, CDC recommends Tdap between 27 and 36 weeks of each pregnancy. In the UK, NHS guidance advises vaccination usually around the mid pregnancy scan at 20 weeks and from 16 weeks onwards, with the aim to vaccinate before 32 weeks for optimal passive transfer. [cdc.gov], [nhs.uk]
After vaccination, a pregnant person generates IgG antibodies that cross the placenta into the fetal circulation. These antibodies can lower the risk of infection and severe outcomes in the early months. This strategy is known as maternal immunization and is now a central pillar of infant protection for multiple respiratory pathogens.
Evidence for transplacental antibody protection extends beyond influenza and pertussis. For example, studies of maternal COVID 19 vaccination show higher neutralizing antibody titers in infants born to vaccinated mothers and reduced risk of infection in the first six months. While COVID 19 is a different pathogen, the mechanism of maternal antibody transfer reinforces the broader principle that vaccination during pregnancy can protect infants who are too young for their own vaccines. [publications.aap.org]
Is it safe to get these vaccines during pregnancy
Yes. Guidance from CDC, NHS and ACOG shows strong safety profiles for inactivated influenza vaccines and Tdap during pregnancy. UK safety monitoring by MHRA and multiple studies have found no increased risk of adverse pregnancy outcomes from pertussis containing vaccines in pregnancy. [cdc.gov], [nhs.uk]
Can I get the nasal spray flu vaccine while pregnant
No. The live attenuated intranasal influenza vaccine is not indicated in pregnancy. Choose an inactivated or recombinant flu shot instead. [acog.org]
If I had Tdap recently, do I still need it in this pregnancy
Yes. Antibody levels wane over time and newborn protection depends on high maternal titers during late pregnancy. CDC recommends Tdap in every pregnancy regardless of prior Tdap history. [cdc.gov]
What if I miss Tdap before delivery
Postpartum Tdap helps protect the mother but does not pass antibodies to the newborn. If Tdap is missed before birth, ask your pediatric team about infant protections and ensure caregivers are vaccinated. [cdc.gov]
The JAMA Network Open findings are consistent with earlier observational studies that showed reduced infant pertussis cases and hospitalizations after maternal Tdap programs were introduced in countries such as England and Brazil, and with reductions in severe influenza outcomes when maternal influenza vaccination coverage increases. Strengthening maternal vaccine uptake through timely counseling and co administration can deliver immediate benefits for infant health. [cdc.gov]
Given the low uptake reported in the Italian cohorts, public health campaigns should emphasize clear messaging about timing, safety and co administration, and make vaccines accessible in antenatal clinics and community pharmacies. Health care teams can also use local data bulletins to target reminders during peak respiratory virus seasons. [acog.org]
In England, routine maternal vaccinations now include pertussis in every pregnancy, influenza during the season and RSV during specified gestational weeks. The UK Health Security Agency has highlighted high rates of flu and pertussis disease and has urged continued efforts to improve uptake in maternity settings. For parents in the UK, check your local NHS trust communications and book vaccines via your midwife or GP. [gov.uk]
The complete routine immunisation schedule details the infant doses that follow, starting at eight weeks, which are essential to maintain protection as maternal antibodies diminish. [assets.pub…ice.gov.uk]
The newest evidence from JAMA Network Open aligns with established recommendations. Vaccinating against influenza and pertussis during pregnancy provides measurable protection for infants during an especially vulnerable window. Parents and clinicians should work together to plan vaccination in the appropriate trimester, co administer when possible and reinforce the infant’s routine immunisation schedule after birth. [jamanetwork.com], [acog.org], [cdc.gov]
This article is for educational purposes and summarizes current evidence and public health guidance. Statistical data describe population level trends and may not apply to individual situations. Always consult your obstetric provider, midwife or pediatrician for personalized medical advice, especially regarding vaccine timing and eligibility during pregnancy. [cdc.gov], [nhs.uk]
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