Pertussis Immunization May Need a Second Vaccine Dose

Pertussis has reemerged as a major public health concern in many countries where vaccine uptake remains high and pertussis has been considered well controlled until recently.

An expanding body of research suggests that some vaccines, previously thought to offer long-term protection against diseases such as pertussis, can actually lose their effectiveness.

The results from a Harvard research team’s analysis identified 31 counties that had geographic clusters of high rates of pertussis in children ages 10 to 14 years old, indicating that immunity from the acellular pertussis vaccine was not sustained.

According to the Centers For Disease Control and Prevention (CDC), in 2012, 84% of adolescents were up-to-date with their Tdap vaccine.

But, the United States reported the highest number of pertussis cases in 2012 since 1955.

This Harvard study suggests a need for the creation of the following:

• a longer-acting pertussis vaccine,
• improved vaccine regimen,
• a revised vaccination schedule for the current acellular pertussis vaccine

Barry R. Bloom, the Joan L. and Julius H. Jacobson Research Professor of Public Health at Harvard Chan School and senior author of this study, said “Our paper shows that 10- to 14-year-olds who had been vaccinated were as susceptible to pertussis as kids who had never been vaccinated. Our work suggests that maybe we should revaccinate teens to boost their immunity.”

According to CDC pertussis, also known as whooping cough, is a highly contagious respiratory disease. It is caused by the bacterium Bordetella pertussis.

Pertussis is known for uncontrollable, violent coughing which often makes it hard to breathe. After fits of many coughs, someone with pertussis often needs to take deep breaths which result in a "whooping" sound.

Pertussis can affect people of all ages, but can be very serious, even deadly, for babies less than a year old.

The CDC reports the widespread use of Tdap vaccination in pregnancy can result in significant decreases in pertussis, particularly in young infants before their first DTaP vaccine dose or who are protected by only 1 dose of DTaP.

The CDC Vaccine Price List including DTaP are posted here.

Author contributions: C.A. designed research; C.A. performed research; M.K. contributed new reagents/analytic tools; C.A., M.K., and B.R.B. analyzed data; and C.A. and B.R.B. wrote the paper. Reviewers: F.C.C., Johns Hopkins Bloomberg School of Public Health; and A.M., Princeton University. Lead author Carlin Aloe, who received the 2016 Dean’s Prize for the outstanding thesis in biology at Harvard University Extension School.

The authors declared no conflict of interest.