By C. Mary Healy, MD
Assistant Professor of Pediatrics, Infectious Diseases Section, Baylor College of Medicine
Director, Vaccinology & Maternal Immunization, Center for Vaccine Awareness and Research, Texas Children's Hospital
The resurgence of pertussis in the past 30 years, despite record high immunization rates in infants and young children, has led some to label pertussis as the most poorly controlled vaccine-preventable disease in the U.S. Between 2009-2010, Texas experienced a record pertussis outbreak, reaching one of the highest levels reported in the state in nearly 50 years. In 2010, California also experienced a widespread pertussis outbreak, affecting more people in any single year since the 1940s. Ten infants less than three months old died from the disease.
To help prevent pertussis in young infants, federal immunization experts recommend two vaccination strategies. First, they recommend that pregnant women receive pertussis booster vaccine (Tdap) during the second half of pregnancy so that the mother’s antibodies will pass to the baby before birth and protect them in the first few months of life. Second, they recommend cocooning of infants. Cocooning helps protect a newborn by encouraging everyone who will be in contact with the infant (mom, family members and any other caregivers) to be vaccinated against pertussis, preferably before the baby’s birth or discharge from the hospital. The idea behind cocooning is to provide a protective shield around the baby against the disease during the first year of life. Babies can’t begin receiving the pertussis vaccination series until they are two months old and are not protected until after their third dose at 6 months of age.
Last month, a new study came out that evaluated the cost-effectiveness of cocooning. The study was conducted in two Canadian provinces with record low rates of pertussis. The authors reported that vaccinating new parents against pertussis is ineffective, expensive, and resource intensive in areas where pertussis rates are low.
As a pediatric infectious disease specialist, I find it troubling that this study may be used as an excuse not to vaccinate parents and other contacts of young infants. First, the findings do not necessarily apply to areas experiencing high rates of pertussis outbreaks. The report also does not consider communities with a large Hispanic population. When compared with other ethnicities in the United States, Hispanic infants are known to have higher rates of infection and death from pertussis. This is a critical point when looking at a state like Texas, where nearly 40 percent of the population is Hispanic. Since 2000, 34 Texas babies have died from pertussis. The Centers for Disease Control and Prevention recognize that cocooning is needed because even if infants receive antibodies from their mother, these antibodies fade away before the infant has had three doses of pertussis vaccine, given at 2, 4, and 6 months of age. Cocooning is also needed to protect infants born prematurely before the mother’s antibodies have been passed to them.
Ultimately, the cost of prevention programs like cocooning must be balanced against the high costs of medical treatments and prolonged intensive care for some infants, as well as the incalculable cost of infant death. It is imperative that we make every effort to protect young infants through prevention strategies like immunizing mothers during pregnancy and cocooning until the elimination of fatal infant pertussis becomes a reality.
Link to original article by Skowronski et al: The Number Needed to Vaccinate to Prevent Infant Pertussis Hospitalization and Death Through Parent Cocoon Immunization
Link to original editorial: Infant Pertussis: What to do next?