Maternal Tdap vaccination reduces pertussis in young infants

There was a sustained decrease in pertussis cases among young infants in the years after maternal Tdap vaccination was introduced in the United States, according to the results of a CDC study published in JAMA Pediatrics.

Since 2011, the CDC has recommended that women receive a Tdap vaccine during each pregnancy to protect infants before they are able to begin getting the vaccine themselves at age 2 months.

“Despite the introduction and widespread use of effective vaccines for infants, children and adolescents, pertussis continues to cause substantial morbidity and mortality in the U.S.,” the researchers wrote in the study. “Pertussis can affect persons of all ages, but infants have the highest burden of disease and an elevated risk of severe pertussis-related morbidity and mortality.”

The researchers conducted an ecological study of 57,460 pertussis cases reported among infants aged younger than 1 year between 2000 and 2019, of which 33.6% occurred in infants aged younger than 2 months.

In the period from 2000 to 2010 — before the CDC recommended that women receive the vaccine during pregnancy — the mean annual pertussis incidence was 165.3 cases per 100,000 infants aged younger than 2 months. Among these youngest infants born after the CDC’s recommendation, the incidence decreased (slope, 14.53 per 100,000 infants per year; P=.001), but was unchanged among infants aged 6 months to less than 12 months (slope, 1.42 per 100,000 infants per year; P=.29).

In a press release, Healio Pediatrics Peer Perspective Board Member José R. Romero, MD, FAAP, FIDSA, FPIDS, FAAAS, director of the CDC’s National Center for Immunization and Respiratory Diseases, said that a mother receiving a Tdap vaccine during pregnancy “offers infants the best protection before they are old enough to receive their whooping cough vaccines.”

“This protection is critical because those first few months are when infants are most likely to have serious complications, be hospitalized or die if they get whooping cough,” Romero said.

The CDC said in the release that women should be vaccinated during the third trimester of each pregnancy “to boost their antibodies and pass those antibodies on to their infants,” and that all people who come in close contact with infants should also be up to date on their pertussis vaccination.

References:

CDC. Pertussis: Summary of vaccine recommendations. https://www.cdc.gov/vaccines/vpd/pertussis/recs-summary.html. Last reviewed Jan. 22, 2020. Accessed Feb. 7, 2023.

CDC. Whooping cough vaccination during pregnancy benefits US infants. https://www.cdc.gov/media/releases/2023/p0206-pertussis.html. Published Feb. 6, 2023. Accessed Feb. 7, 2023.

Skoff TH, et al. JAMA Pediatr. 2023;doi: 10.1001/jamapediatrics.2022.5689.