Prenatal vaccination, followed by cocooning, is the most effective strategy for reducing pertussis complications and death in young infants, according to recommendations from the Global Pertussis Initiative (GPI).

GPI is an expert scientific forum that aims to reduce the worldwide burden of pertussis, particularly in infants under 6 weeks old who are too young to be vaccinated.

Infants under 6 months of age are at the highest risk for death and complications from pertussis, but the first pertussis vaccine dose is not recommended in most countries until 6-8 weeks of age.

“There is strong evidence that the pregnancy booster directly protects young infants through the transfer of maternal pertussis antibodies, in addition to being effective, safe, and well tolerated,” Dr. Kevin Forsyth of Flinders University in Adelaide, Australia, and his associates reported online. “A key benefit of this approach is that it provides protection to the very young from birth until infant-generated immunity is achieved from the primary series of pertussis immunization,” they wrote (Pediatrics 2015 May 11 [doi:10.1542/peds.2014-3925 ]).

The U.S. Advisory Committee on Immunization Practices recommends the Tdap booster during the third trimester of pregnancy, and similar recommendations exist in Argentina, Belgium, Israel, New Zealand, and the United Kingdom. Multiple studies have found higher levels of maternal pertussis antibodies and lower disease burden among infants born to mothers who received a pregnancy booster, compared with those who did not. Based on this evidence, the GPI recommends maternal prenatal vaccination as the primary strategy for protecting infants from pertussis. If prenatal immunization is not possible or families want extra protection, the GPI recommends that all individuals with close contact with infants under 6 months old be vaccinated with Tdap during pregnancy or immediately post partum.

“A high priority should be given to achieving a complete cocoon, defined as full immunization of the family, since the robustness of protection against pertussis is a function of the number of infant contacts vaccinated,” the authors wrote. If not everyone can be vaccinated, the parents should be vaccinated, or at least the mother, though little real-world data exist regarding the effectiveness of the cocooning strategy.

Support for this writing and the Global Pertussis Initiative are funded by Sanofi Pasteur. Drs. Forsyth, Plotkin, Tan, and Wirsing von König have received honoraria, consulting fees and/or grants from Sanofi Pasteur, Merck, GlaxoSmithKline and/or Novartis. Dr. Tan has received personal fees from GlaxoSmithKline Biologicals and Sanofi Pasteur.

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