Whooping cough, caused by the bacterium bordetella pertussis was a commonly seen infection prior to the 1950's, after which widespread immunization helped to significantly reduce frequency of this disease. Whooping cough (or pertussis) presents as a nasty cough, lasting up to three months, in adults. But whooping cough in infants can be deadly.
Frequency of whooping cough outbreaks reduced tremendously in the years following use of the vaccine, however there has been a resurgence over the past few decades, rising substantially to a peak in 2012. There have been various reasons for the uptick in whooping cough outbreaks, and the anti-vaxx community is actually not (fully) to blame for this one. Many of the outbreaks can be explained by waning immunity in adults and older children, inadequate re-immunization (or booster shots) in teens and adults, and, to a much lesser extent, the anti-vaxx community advocating delaying vaccines in infants and young children. The outbreak numbers in 2012 reached higher than those seen in over five decades, with nearly 50,000 cases in the United States alone, and nearly 90,000 deaths worldwide.
Traditionally, the pertussis vaccine is given as a combination with the diphtheria and tetanus vaccines (DTaP, "D" for diphtheria, "T" for tetanus, and "aP"for acellular pertussis) in infants beginning at age two months, followed by boosters at four months, six months, and nine months. This schedule leaves an immunization "hole" between birth and the first months of life, before immunity (defined as detectable serum antibodies to the pertussis toxin) is obtained. As infants are at highest risk of mortality from whooping cough infections, which are commonly transmitted from un-immunized adults with milder, perhaps unrecognized cases of the disease, in 2013 the CDC recommended that pregnant women in the third trimester should receive a booster in the form of TdaP (tetanus, diphtheria, acellular pertussis). This would enable the unprotected newborn to receive maternal pertussis antibodies, providing some pertussis immunity in the early months of life.
A recent randomized, prospective study performed at the National Centre for Immunisation Research and Surveillance of Vaccine Preventable Illnesses in Australia assessed the safety and efficacy of instituting an acellular pertussis (aP) immunization program to newborns. In developing countries, especially where vaccination is not used universally, the mortality from pertussis in infants under age two months remains high.
Maternal access to pertussis vaccination during pregnancy is not routine in some populations, leaving newborns more vulnerable to life-threatening pertussis infections. The study group administered the acellular pertussis vaccine to a randomized half of cohort of 440 full-term infants in the first five days of life. At 6, 16, and 24 weeks of age, all infants received the standard DTaP immunization. At age 10 weeks, 93.2% of the cohort immunized at birth were found to have serum antibodies to the pertussis toxin, as opposed to 50.8% of the cohort having received the first immunization at age 6 weeks. There was a four-fold difference in antibody levels between the two groups, even if the infant's mother had received a TdaP booster during pregnancy. These differences in antibody levels were statistically significant. There were no major adverse vaccine-related events in either group.
Some populations have limited access to prenatal pertussis immunization boosters or routine TdaP boosters in older children and adults. Administering the acellular pertussis (aP) vaccine to newborns may confer life-saving immunity to whooping cough infections in this vulnerable population.
