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!
Summer O'Neill says
Thank you, Dr. Swanson. I read about this on NPR yesterday and felt myself wondering…”What would Dr. Swanson say?” Your post is both timely and appreciated coming from the mom of a one year old who is up to date with his Tdap shot (as is mom, dad and the grandparents) Thanks!
Wendy Sue Swanson, MD, MBE says
Glad it was helpful! And glad your family’s community is up-to-date.
Amelia D. says
The only point here that I don’t see supported is the cocooning thing. Hasn’t it been established via that huge study in Canada that cocooning does practically nil, at least in the context most of us are in? I thought the failure of cocooning was part of the new, better strategy of the third trimester booster. I haven’t seen any comparable study on cocooning, much less one showing a “POWERFUL” protective effect. Obviously, this is no reason to skip any of the other shots – my point is just that going to the extreme of requiring house guests to get a booster would appear to be less than scientifically sound. https://cid.oxfordjournals.org/content/early/2011/12/01/cid.cir836.abstract?sid=446ff7dc-43cb-4f25-9696-a8dea1459a01
Of course, I could also be missing some other piece of data, in which case I would love to be directed to it. 🙂
Wendy Sue Swanson, MD, MBE says
Amelia,
Thanks for this important and smart question. More to come — I’ve emailed some national experts as well and will also do some digging myself on how (and with what) we can “defend” the cocooning advice with data.
Dr WSS
Katarina Witt says
It was not the Tdap that was reformulated in the 1990s, it was the DTP vaccine that was reformulated to DTaP. It is confusing, but it’s an important difference. Until Tdap came out in 2005, there was no vaccine for people over 7 years of age. Tdap was (is) a new vaccine that came out as I said in 2005, for pre-teens and adults. Its use has changed a bit over time, but the thumbnail sketch is that it is for preteens and anyone older who has not had a dose. One dose is supposedly all the average person needs. Pregnant women should get a dose in each pregnancy, to pass on antibodies to their babies.
DTP to DTaP is a different vaccine. DTP (whole cell, sometimes abbreviated DTwP) came out in the 1940s; 1949 I believe. It unfortunately causes a lot of adverse events, especially high fever with febrile seizures. The parents of the 1970s started having issues with these fevers and seizures, there were accusations that the vaccine caused permanent brain damage, death, etc. Most of this stuff was undocumented, but people believed it anyway, and started refusing vaccinations big time. So researchers worked on making a vaccine with fewer side effects and came up with DTa(for acelluar)P vaccine. It does have fewer side effects, but apparently is also less long-lasting.
Wendy Sue Swanson, MD, MBE says
Agreed, Katarina. Sorry if my messaging was confusing —
The new data just helps us see the effect of Tdap (the 11 year-old booster) on these tweens who never had “whole cell” DTP….they’ve only had DTaP.
Linda Friede says
I know this is an old post, but I have a question that I thought you might be able to help me with. I am 57 years old, healthy, and of course, had all of the required immunizations as a child, including the whole-cell whooping cough vaccine. In 2007, I had the Tdap booster.
My daughter-in-law has asked that we update our vaccinations before the birth of their baby (due in two weeks). I called my doctor’s office, and my doctor indicated that I do NOT need a Tdap booster, as there is only one necessary after age 19. He did say that I should get a Tetanus booster, but not the whole Tdap.
My daughter-in-law believes that I should get a second Tdap, and if they are to have additional children in the future (beyond three years), she would require us to have another! I called the CDC, Mayo Clinic and my doctor, and they disagree with her, and say that the Tdap I received in 2007 is all that is necessary (with the Tetanus booster, of course). Do you have additional information about a second Tdap for grandparents? Thank you very much