Two new Pediatrics studies are out this week teaching us more about the effectiveness of the whooping cough vaccine. Lots to learn about how we protect babies and reminders here why we’re immunizing moms during EVERY pregnancy:

  • First, the good news: traditionally we have been trained to tell parents that the first shots we give during infancy aren’t fully protective for infants but rather the beginning of creating immunity against the diseases they prevent. However, a study conducted by researchers at the CDC looked back at cases of infants with pertussis from 1991-2008 and they found evidence that babies who received their whooping cough shot as early as they could, at the age of 6 weeks, were less likely to be hospitalized and/or die from the infection. Wonderful news! The first evidence out there that even that first shot, when given as early as possible, helps protect very young infants who are most at risk from whooping cough. New parents can increase protection, even during outbreaks like we’re having right now, by getting their babies immunized on-time and as early as possible.
  • The not so good (but important) news: the effectiveness of the Tdap shot given to young teens (explained more below) doesn’t always provide long-lasting protection and wanes significantly in the years after the 11-year-old booster dose is given. New research out found after 1 year, about 70% of teens are still protected from the booster, but by 4 years after the shot only about a 1/3 of them are. More:

Vaccine Changes May Be Affecting Outbreaks

2015 is seeing a large number of whooping cough cases reported in Washington State and most of them in teenagers 18 years or younger. Since the start of the year, 456 cases of pertussis have been reported as of May 2nd, 2015. That’s compared to 98 cases reported during the same time period in 2014. The predominance of children with the infection may be in part to a change in the Tdap vaccine back in 1990’s when we switched from a vaccine that was “whole cell” to an “acellular” vaccine. The reason for the switch was side effects, the new shot fortunately doesn’t provoke as many fevers or subsequent seizures in young babies. However, every change comes with trade-offs; teens now growing up have never had a dose of the “whole cell” shot. And evidence out this week confirms what we’ve suspected, if teens have never had a dose of the old vaccine, their protection against whooping cough fades after immunization. Protection is not lost, it’s just isn’t as robust. In the newly released study evaluating effectiveness during a 2012 epidemic in Washington State, researchers and epidemiologists found the vaccine is 73% effective one year after the 11-year-old booster and only about 35% effective 2-4 years after the booster is given. As a reminder, thankfully those of us who did have a whole cell vaccine at some point in our life likely have longer lasting protection from these boosters. To learn more, listen to this recent interview with Chas DeBolt, an epidemiologist at the Washington State Department of Health, who conducted the study.

Babies Are Better Protected

In perspective, we’re still protecting the most vulnerable — newborns and young infants. The Pediatrics study out this week shows the very first dose of the pertussis vaccine, given to infants at 6 weeks of age (DTaP), is protective against pneumonia, hospitalization and death! This means these young babies previously thought to be solely reliant on parents and family members for cocooned protection are better protected than we knew. This is wonderful news for parents, as pertussis can cause severe respiratory distress, pauses in breathing or even cause infants to stop breathing. Parents can feel even better about ways they are protecting their immunized babes.

Who Needs To Be Immunized?

The realization the whooping cough vaccine’s fading effectiveness in teens doesn’t change the fact that vaccination is still the best line of defense against whooping cough. While I encourage everyone to make sure they’re up to date with their immunizations, the following groups in particular need to be protected for both their own health and the health of those closest to them.

  • Pregnant women! In every pregnancy moms should be given the Tdap during their third trimester. We want their own immune system primed prior to delivering a baby who is at greatest risk. Moms should get this at least 2 weeks before delivery.
  • All babies at 6-8 weeks of age: No reason to wait on the first set of shots, typically called the “2-month immunizations.” They can all be given as early as 6 weeks. If you’re living in an area where there are whooping cough outbreaks, get your newborn into their provider’s office at 6 weeks. Protection against serious side-effects in the rare case that they are exposed to whooping cough is worth being totally organized about this!
  • Children & Teens
    • Infants, toddlers and children get the DTaP vaccine also at 4, 6, & 15 months of age. Keep doing this!
    • Children get a DTaP booster before Kindergarten at age 4 and children get it at age 10 or 11 years. No reason to wait!
  • Adults, Dads & Grandparents who will be around a new baby also need protection. Moms tend to get protected and often in the chaos of expecting a new baby some other family members forget. Cocooning your baby is still POWERFUL. Every layer of protection you can surround an infant with is an opportunity to keep them healthy — get any house guests up-to-date!