This year, 2012, was one of the worst whooping cough (Bordetella pertussis) outbreaks in the USA for the past 70 years, which included an outright epidemic in Washington state. Some of the reasons for the spread of the disease were a reduced whooping cough (Dtap) vaccination rate and reduced effectiveness of the Dtap (or TDaP) vaccine. Whooping cough is a serious disease, especially to children under the age of one year old, who have not been fully vaccinated. According to the Centers for Disease Control and Prevention, of those infants who are hospitalized with pertussis about:
- 1 in 4 (23%) get pneumonia (lung infection)
- 1 or 2 in 100 (1.6%) will have convulsions (violent, uncontrolled shaking)
- Two thirds (67%) will have apnea (slowed or stopped breathing)
- 1 in 300 (0.4%) will have encephalopathy (disease of the brain)
- 1 or 2 in 100 (1.6%) will die
One of more important concerns with the outbreaks of pertussis has been that adults with lapsed immunity have picked up the infection and passed it to these unvaccinated or partially vaccinated infants (usually less than 1 year old).
In an article published in Epidemiology this week, the authors described the benefits of cocooning, a strategy of protecting infants from pertussis by vaccinating those in close contact with them. According to the report, “targeted vaccination of mothers would approximately halve the probability of infants’ infection. Vaccination of siblings is less effective in preventing transmission within the household, but may be as effective overall because siblings more often introduce an infection in the household. Vaccination of fathers is expected to be least effective.”
What we can conclude from their results is that vaccinating mothers is most effective, because they are probably most often in contact with the child. However, siblings could be more in contact with others who might be infected with pertussis, so vaccinating them can be the most effective part of cocooning an infant from pertussis. Of course, if we assume that a family has kept all children up-to-date with vaccinations, then the cocooning strategy is at its strongest without further effort.
The Advisory Committee on Immunization Practices (ACIP) has recommended cocooning with Tdap or DTaP vaccines since 2005 and continues to recommend this strategy for all those with expected close contact with newborns, including family members, caregivers, and friends. ACIP recommends that they get vaccinated at least two weeks before coming into contact with infants. With the increase in pertussis rates, this strategy may be invaluable to protecting the newborn.
Vaccines Save Lives.