A recent whooping cough epidemic in California has affected 4,223 people and sadly resulted in the deaths of nine young babies. But while some pediatricians are keen to blame parents who don’t vaccinate, the issue is far more complicated than that.
The California epidemic is not the first time a whooping cough epidemic has occurred in recent years and the problem of vaccine waning has been discussed in medical journals for decades.
Vaccinations don’t last for a lifetime. In fact, the duration of the whooping cough vaccine is thought to be only about five years. A Polish study found that only 45 percent of vaccinated eight year olds still had any detectable antibodies to pertussis: "Protective antibody levels were detected in 70%, 58%, and 45% children aged 6, 7, and 8, respectively. It shows that decrease of immunity may cause increasing number of pertussis in children above 5."
This study and others like it led to the introduction of a pre-school booster dose of the vaccine. Given its limited time span, even the booster will have worn off by the time the child is 10 or 12. This is why large numbers of cases are now occurring in previously vaccinated teenagers and parents. They can then spread the infection to newborn babies. Babies aren’t considered immune to whooping cough until they have had three or four doses of vaccine (depending on what country you’re from and what schedule you’re working to). The third dose is given at six months old. The higher danger period is in the first six months of life with the majority of deaths occurring before then, so in fact even if a parent has chosen to vaccinate, which most do, their baby isn’t considered immunized in that riskier period.
Vaccinating Older People
To counter this problem, medical policy makers have begun to advise that new parents be vaccinated with DtaP to protect their babies, in addition to introducing more boosters for teenagers. This is a new policy with the theory of minimizing an infant's exposure to pertussis by vaccinating those around him.