Pertussis: the 100 Days Cough
Pertussis is also known as whooping cough. It is caused by a bacteria called Bordetella pertussis, a tiny bacteria that is spread by airborne droplets (from coughing and sneezing).
 | In the beginning the illness looks like a common cold, with a fever, sneezing, runny nose, and a normal sounding cough. After 1-2 weeks, most of the symptoms resolve but the cough sticks around and just gets worse. Many kids will develop what are called “paroxysms” of coughing, meaning they will have bad coughing fits where they will cough several times in a row, followed by a gasp for breath (the “whoop” in whooping cough). |
Kids may cough so much they throw up, give themselves nosebleeds, or break blood vessels in their eyes (a generally harmless condition called subconjunctival hemorrhage).
How Common is Pertussis?
In 2014 there were 32,971 cases of pertussis reported to the CDC (and most likely there were many more cases that were treated at home and went unreported). So - very common!
Is Pertussis Dangerous?
For kids under one year old, pertussis is a very dangerous illness and can be fatal. It is especially dangerous for babies under 6 months. This is because they can cough so much they they just can’t breathe, and they suffocate. Around one kid in 1,800 who gets pertussis does not survive - of these almost 90% are infants under 3 months old.
The 100 Days Cough
| While most kids get over pertussis in a few weeks, this cough can last a LONG TIME. It is sometimes referred to as the “Hundred Days Cough,” because it can literally last for 100 days (though it is usually only 1-6 weeks). In addition, after a kid recovers from pertussis and their cough goes away, they may still have an occasional coughing bout now and again, and they are often extra susceptible to upper respiratory infections for several months. |  |
The other issue is that a kid can get pertussis over and over again - unlike a lot of infections, getting pertussis once doesn’t make you immune.
The Pertussis Vaccine: It Puts the “P” in DTaP
Pertussis is the “P” in the DTaP vaccine (the whole vaccine is Diphtheria, Tetanus, and Pertussis). In older kids and adults, the vaccine is called TDaP, which is the same combination of vaccines (Tetanus, Diphtheria, and Pertussis) but with a different formulation that works better for a mature immune system.
NOTE: The DTaP vaccine is how a kid gets vaccinated against tetanus. You can not get your child (or yourself) at vaccine for tetanus alone - it is always given either with pertussis and diphtheria (DTaP) or with diphtheria (TD).
NOTE: The DTaP vaccine is how a kid gets vaccinated against tetanus. You can not get your child (or yourself) at vaccine for tetanus alone - it is always given either with pertussis and diphtheria (DTaP) or with diphtheria (TD).
When is the Pertussis (DTaP) vaccine given?
More recently it’s become conventional to give the first DTaP vaccine towards the end of pregnancy, somewhere between weeks 27-36. Some of the antibodies produced in the pregnant person’s body will be able to pass through the placenta at this age, which gives a small degree of protection to the child.
The CDC recommends that kids starts getting DTaP at 2 months, again at 4 months and 6 months. Booster shots are given at 15 months, 18 months, and a final booster some time between ages 4-6.
NOTE: Newborns are never given pertussis vaccines because their immune systems are unable to produce antibodies until they are around 2 months old.
The CDC recommends that kids starts getting DTaP at 2 months, again at 4 months and 6 months. Booster shots are given at 15 months, 18 months, and a final booster some time between ages 4-6.
NOTE: Newborns are never given pertussis vaccines because their immune systems are unable to produce antibodies until they are around 2 months old.
How Effective is the Pertussis Vaccine?
DTaP, which is the type of pertussis vaccine given to infants and young children, is effective in 85% of children, while the other 15% may get some or no protection against the disease. That number changes every year as new forms of pertussis bacteria, which the vaccine is not effective against, become more prevalent. Immunity from this vaccine fades over time: by 5 years after the last scheduled booster, just 70% of kids are still immune (by that age, however, the condition is generally much less serious!).
In adults the vaccine is less effective: only 70% of adults will be immune to pertussis one year after getting their Tdap shot (the adult version of DTaP), while after 4 years this drops down to 35%.
Are There Risks Associated with the Pertussis vaccine?
Like many vaccines, the DTaP vaccine has all the usual risks, such as high fever, seizures, and anaphlaxis. The DTaP vaccine also contains a large amount of aluminum, well above the safe maximum recommended by the WHO. Aluminum is a known neurotoxin and there is some concern that aluminum may cause alterations in cognition and has been indicated in certain neurological autoimmune conditions.
Another significant concern with the DTaP vaccine is it’s association with asthma. The rate of asthma in kids who have gotten the DTaP vaccine is significantly higher than in kids who have not.
A study in the UK of 448 children and adolescents showed that about 1% of the children who had never received any immunizations had asthma, and 3% of those who had been given vaccinations other than pertussis had asthma. In contrast, 11% of those kids who got the pertussis vaccine went on to develop asthma.
While pertussis in infancy is a very serious illness, it’s important to remember that asthma is a serious illness as well - while the overall mortality rate of pertussis is 0.05%, asthma, which can be a lifelong illness, has an overall yearly mortality rate of 0.02% (3,630 people per year).
A study in the UK of 448 children and adolescents showed that about 1% of the children who had never received any immunizations had asthma, and 3% of those who had been given vaccinations other than pertussis had asthma. In contrast, 11% of those kids who got the pertussis vaccine went on to develop asthma.
While pertussis in infancy is a very serious illness, it’s important to remember that asthma is a serious illness as well - while the overall mortality rate of pertussis is 0.05%, asthma, which can be a lifelong illness, has an overall yearly mortality rate of 0.02% (3,630 people per year).
When getting a DTaP vaccine is
an especially good idea:
- If your child is in daycare
- If you, your child, or close caretakers are frequently around other children (especially unvaccinated kids)
- If your child has any other medical condition that would make a pertussis infection especially dangerous for them, such as immunodeficiency or Down’s syndrome
- If your child has a medical condition that might make them especially susceptible to contracting pertussis, such as asthma
- If your child is around unvaccinated infants, other children with immunodeficiency, or any other medically vulnerable kids (in order to help protect the other child)
My baby isn’t vaccinated against pertussis.
How can I protect her?
One of the best ways you can protect your newborn or your unvaccinated infant is by reducing her or his potential exposure to the bacteria. You can do this by:
- Asking adults who are around your child to get their Tdap vaccinations for that year (sometimes called “Infant Cocooning”). Adults and adolescents in your child’s immediate environment are much less likely to have negative side effects from the vaccine - and they are the most common way for an infant to get pertussis!
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In Conclusion...
Pertussis can be a really serious condition in babies - and a real pain for families with older kids (that “100 days cough” is not an exaggeration). The choice of whether or not to vaccinate is very personal and should be made with careful consideration - and a conversation with a trusted pediatrician, of course!
