In 2014, there were over 32,000 cases of pertussis in the United States. This represented a whooping 15% increase in incidence over the prior year (pun intended). The incidence rates for pertussis among babies exceeds all other age groups. The majority of pertussis deaths are in babies less than 3 months of age.
In California in 2015, there were over 10,000 cases of pertussis. Of the counties reporting pertussis, the six top counties with “rates substantially higher than statewide average” were all Partnership counties. These are Marin, Sonoma, Napa, Yolo, Humboldt and Modoc counties. Of worrisome note, only 16% of mothers of infants diagnosed with pertussis in 2015 had been vaccinated during pregnancy with Tdap. A CDC study in 2014 found that only 14% of pregnant women had been vaccinated during the pregnancy.
For many years, the American College of Obstetrics and the Advisory Committee on Immunization Practice recommended an approach to pertussis prevention in neonates called “cocooning”. This consisted of administering Tdap vaccine to all women in the post-partum period, and all other family members and caregivers who are in the infants environs to provide a “cocoon” of protection. This strategy has proved insufficient and ineffective as the epidemic of pertussis continues to grow. One key gap was that cocooning left a minimum of a two month gap of exposure between birth and receiving their first immunization.
Confronted with the inadequacy of the cocooning approach, the recommendations were revised by ACIP in 2013 to recommend the following:
- All pregnant women regardless of prior immunization history should receive the Tdap vaccine during pregnancy.
- Tdap should be given between 27 and 36 weeks of gestation to maximize the maternal antibody response, although it can be given at any point during pregnancy.
- If not given during pregnancy, a Tdap should be given in the post-partum period.
- If a tetanus immunization is needed for wound management during the pregnancy, Tdap is the preferred vaccine.
TAKE HOME: if you care for pregnant women in your practice, ensure that ALL women are offered Tdap during pregnancy, optimally during weeks 27-36.