Global Pertussis Initiative Stresses Vaccination in Pregnancy

Troy Brown, RN

May 12, 2015

Pregnant women should be vaccinated against pertussis during each pregnancy to protect their infants from the infection, according to new recommendations from the Global Pertussis Initiative (GPI). The GPI is an expert scientific forum charged with addressing the global burden of pertussis.

Families can also use a second, less effective preventive strategy known as cocooning, which entails vaccinating all individuals who will have close contact with the infant.

Kevin Forsyth, MD, PhD, from the Department of Paediatrics and Child Health, Flinders Medical Centre, Flinders University, Adelaide, Australia, and colleagues present the recommendations in an article published online May 11 in Pediatrics.

Pertussis is transmitted via aerosol droplets. Although vaccines are available and coverage is high in most regions of the world, the disease remains a global health problem, the authors write.

"Many countries with long histories of routine pertussis vaccination have experienced a recent resurgence of the disease, particularly among older children, adolescents, and adults," the authors explain. "One factor that may be contributing to this is waning immunity, which has been observed despite vaccination."

Infants aged 6 months and younger are at increased risk for pertussis-related complications and death. In addition, infants are at increased risk of contracting the disease because the youngest infants, those aged 0 to 6 weeks, are too young to be vaccinated, and older infants are at risk until their vaccinations have been completed.

Vaccination during pregnancy is the primary and most important preventive strategy because it offers direct protection to the infant through the passive transfer of pertussis antibodies from the mother to the fetus, the authors write. It is safe and effective and has logistic advantages over the cocooning strategy.

Cocooning provides indirect protection to infants. Families who use this strategy should undertake complete cocooning or full immunization of the family. When this is not possible, immunizing only the mother will provide limited protection for the infant.

The authors note that cocooning can be costly and resource intensive to implement because of the need to secure increased staffing and obtain reimbursement or alternate funding. In addition, it may be difficult to gain the acceptance of families.

GPI Recommendations

Maternal immunization during pregnancy should be the primary prevention strategy. If that is not possible, or if families desire further protection for their newborns, the GPI recommends immunizing all individuals who have close contact with infants younger than 6 months according to local health authority guidelines.

"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 write. "If a complete cocoon is not possible, then the next priority is vaccination of both parents, followed by the mother only."

The authors caution that real-world data on the clinical effectiveness of pertussis vaccination during pregnancy and of cocooning are limited, particularly in the form of large clinical trials. Future recommendations will incorporate new data as they become available.

"In 2014, the >10 000 reported cases of pertussis in California surpassed a recent previous record set in 2010 and all other records in the postvaccine era," Mark H. Sawyer, MD, from the Division of Infectious Diseases, Department of Pediatrics, University of California San Diego School of Medicine, Rady Children's Hospital; and Sarah S. Long, MD, from the Division of Infectious Diseases, Department of Pediatrics, Drexel University College of Medicine, St Christopher's Hospital for Children, Philadelphia, Pennsylvania, write in an accompanying editorial.

"The national experience mimics that of California, with rising numbers of cases widespread over the last 4 years. Sadly, the rising disease rate is accompanied by an increase in deaths from pertussis, almost exclusively in young infants."

However, data show that pertussis vaccination of pregnant women is safe and effective, they note. "This is good news, especially for infants. In California, the 9120 reported cases of pertussis in 2010 led to 10 infant deaths, whereas the >10 000 cases in 2014 led to only 3 infant deaths," the editorialists explain.

"It is reasonable to assume that pertussis immunization during pregnancy, which has been steadily increasing since its emphasis in California beginning in 2010, has contributed to the reduction in infant deaths."

Dr Forsyth reports receiving honoraria from Sanofi Pasteur. One coauthor is a paid consultant to Sanofi Pasteur, Merck & Co, and GlaxoSmithKline Biologicals. Another coauthor reports receiving grants from Merck & Co and Sanofi Pasteur and personal fees from GlaxoSmithKline Biologicals and Sanofi Pasteur. Another coauthor reports receiving honoraria for attending meetings sponsored by Sanofi Pasteur, GlaxoSmithKline Biologicals SA, and Novartis Vaccines. The editorialists have disclosed no relevant financial relationships.

Pediatrics. Published online May 11, 2015. Article abstract, Editorial full text


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