Maternal Tdap vaccination could provide the most effective protection against pertussis in newborns

Recent findings, published in the journal Pediatrics, have suggested that a tetanus toxoid, reduced diphtheria toxoid and acellular pertussis (Tdap) vaccination during pregnancy could be highly protective against pertussis in newborns, particularly during the first two months of life.

In this study, researchers at the Kaiser Permanente Vaccine Study Center (CA, USA) investigated the effectiveness of this maternal pertussis vaccine on 148,981 infants born between the years 2010 and 2015.

In this retrospective cohort study, the vaccination demonstrated 91.4% effectiveness in the first two months of life, and 69.0% during the entire first year.

Study center director and senior author, Nicola Klein, compared these findings to other previously used vaccination strategies: “The strategy of immunizing pregnant women to boost maternal antibody transfer appears to be more effective for protecting young infants against pertussis than are attempts at ‘cocooning,’ in which mothers and other persons in close contact with newborns are vaccinated after the birth.”

The results of this study strongly support the recommendation made by the Centers for Disease Control and Prevention’s Advisory Committee on Immunization Practices (ACIP), which states all pregnant women should receive a Tdap vaccination.

Even though some protection from this respiratory infection is passed on to newborns through maternal transfer, the effects of these protective antibodies is thought to be almost completely lost by 4 months of age.

Currently in America, parents are recommended to have their children vaccinated in three doses at 2, 4 and 6 months of age.Some concerns have been raised as to whether maternal Tdap vaccination negatively impacts the protective effects of this recommended infant vaccination strategy.

To investigate this further, the effectiveness of maternal vaccination was not only observed before infants were vaccination, but also in infants who were given the three-dose Tdap vaccination.

“The results of this study demonstrate that maternal Tdap administered during pregnancy provides the best protection against pertussis, which strongly supports ACIP’s current recommendation to administer Tdap during each pregnancy,” commented Klein.

“Maternal Tdap administered during pregnancy was highly effective at protecting infants against pertussis prior to their first dose of DTaP. Through the first year of life, maternal Tdap continued to provide protection without interfering with DTaP. It is reassuring that at every level of DTaP exposure, children with maternal Tdap are better protected.”

Sources: Baxter R, Bartlett J, Fireman B, Lewis E, Klein NP. Effectiveness of Vaccination During Pregnancy to Prevent Infant Pertussis. Pediatrics. doi:10.1542/peds.2016-4091 (2017) (Epub ahead of print);


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