November 06, 2018
On October 5, 2018, the Portland Press Herald published an op-ed titled, “Declining vaccination rates play role in rise of pertussis cases, but they do not entirely explain the high incidence of whooping cough in Maine.”
The piece was written by Associate Professor Meghan May, Ph.D., and Haley Etskovitz (COM, ’21) of the University of New England College of Osteopathic Medicine. They point to a recent news report about the rising number of pertussis cases in York County, Maine that quoted health experts who attributed the high numbers to an increase in unvaccinated children.
“While declining vaccination rates have absolutely played a role in the state’s rising rate of pertussis, they do not explain it entirely,” May and Etskovitz write. “Maine is one of several states that has seen cases of pertussis in children who are fully vaccinated, on time and on schedule. How is it possible that a disease that was once well-controlled by a vaccine has started appearing in fully immunized children?”
May and Etskovitz explain that they recently completed a study exploring this very question.
“We explored the genetic diversity of Bordetella pertussis, the microbe that causes whooping cough. We looked at the pieces of B. pertussis found in the DTaP and TDaP vaccines, and studied how those pieces interact with the immune system of a vaccinated person. Our findings suggest that it comes down to Darwinism: survival of the fittest bacteria.
When we are vaccinated, our immune system mounts a response targeted specifically to the components in that vaccine. Every bacterium present with an identical copy of the vaccine component (in this case a protein called pertactin) will be killed by the immune system. If there are a few bacteria present with a slightly different version of pertactin, they become harder to kill. Over time, these strains with slightly different versions start spreading in the population and progress from being ‘harder to kill’ to being ‘impossible to kill.’”