How does that work?
How Contagious is Pertussis?
Pertussis is very contagious, but not quite as contagious as other vaccine-preventable diseases, such as measles.
That’s why the focus on controlling pertussis outbreaks is usually looking at close contacts – those who were within about 3 feet for at least 10 hours a week or who had direct face-to-face contact with the person when they were contagious.
So when you get a letter about a possible case of pertussis in your child’s school, it may be a a general warning and not that your child is at risk.
How do you get pertussis?
“Persons with pertussis are infectious from the beginning of the catarrhal stage through the third week after the onset of paroxysms or until 5 days after the start of effective antimicrobial treatment.”
Manual for the Surveillance of Vaccine-Preventable Diseases
Spread by respiratory droplets (coughing and sneezing), pertussis symptoms usually start about 5 to 10 days after being exposed to someone else who is in the early stage of their pertussis infection.
While pertussis symptoms can linger for up to 10 weeks, someone who has pertussis is most contagious during the first 2 or 3 weeks of symptoms.
Is Your Child Protected Against Pertussis?
Two pertussis vaccines, DTaP and Tdap, help protect us against pertussis.
In the Unites States, they are routinely given as a primary series (DTaP) at 2, 4, and 6, and 15 to 18 months, with a booster dose at age 4 years. And then a booster of Tdap at age 11 to 12 years. Later, Tdap is given again during each pregnancy, between 27 and 36 weeks gestation. Adults who have never had a dose of Tdap should get caught up, especially if they will be around a baby.
Protection from the pertussis vaccines wanes or wears off, so even fully vaccinated children and adults can still get pertussis. Of course, you are much more likely to get pertussis if you are unvaccinated and you will likely have more severe illness if you are unvaccinated.
Postexposure Antimicrobial Prophylaxis for Pertussis
Fortunately, as with meningitis was caused by Neisseria meningitidis and Haemophilus influenzae type b (Hib), taking antibiotics after being exposed to someone with pertussis can help prevent you from getting sick.
There are only specific situations for which this type of postexposure antimicrobial prophylaxis is recommended though, so for example, you wouldn’t usually give everyone in a school antibiotics because a few kids had pertussis.
Why not give antibiotics to everyone who might have been exposed to someone with pertussis?
“…there are no data to indicate that widespread use of PEP among contacts effectively controls or limits the scope of pertussis outbreaks.”
Postexposure Antimicrobial Prophylaxis
In addition to the fact that it likely wouldn’t stop our pertussis outbreaks, overuse of antibiotics can have consequences.
Situations in which postexposure antibiotics (azithromycin, clarithromycin, and erythromycin, or Bactrim) likely would be a good idea include:
- household contacts of a known pertussis case
- to help control an outbreak in a limited closed setting, like a daycare
- contacts of a pertussis cases who are at high risk for severe pertussis, including pregnant women, infants, especially infants less than 4 months old, and people with chronic medical problems
- contacts of a pertussis cases who are also contacts of someone who is at high risk for severe pertussis
What if you were exposed to someone with pertussis and have already gotten sick?
If your child was exposed to pertussis and is now coughing, then in addition to antibiotics, pertussis PCR testing and/or culture will also likely be done to confirm that they have pertussis. And remember that their contacts might need postexposure antibiotics.
Kids who have been exposed to pertussis and who have been coughing for more than 3 weeks won’t need antibiotics or testing, as it is too late for the antibiotics to be helpful and likely too late for testing to be accurate. Fortunately, after 3 weeks, they should no longer be contagious.
What to Do If Your Unvaccinated Child Is Exposed to Pertussis
Unvaccinated kids who are exposed to pertussis should follow the postexposure antimicrobial prophylaxis guidelines.
They should also get caught up on their immunizations, including DTaP if they are between 2 months and 6 years, or Tdap if they are older.
What to Do If Your Vaccinated Child Is Exposed to Pertussis
Since protection from the pertussis vaccines wanes, even kids who are fully vaccinated should follow the postexposure antimicrobial prophylaxis guidelines if they are exposed to pertussis.
Then why get vaccinated?
Again, being vaccinated, your child will be much less likely to get pertussis than someone who is unvaccinated. Even though the pertussis vaccine isn’t perfect, it has been shown that children who had never received any doses of DTaP (unvaccinated children) faced odds of having pertussis at least eight times higher than children who received all five doses.
What to Know About Getting Exposed to Pertussis
Talk to your pediatrician if your child gets exposed to pertussis to make sure he doesn’t need post-exposure prophylaxis to keep him from getting sick, even if you think he is up-to-date on his vaccines.
More on Getting Exposed to Pertussis
- CDC – Postexposure Antimicrobial Prophylaxis for Pertussis
- CDC – Letter of Guidance for Parents and Clinicians during Outbreaks
- Pertussis in Schools
- CDC – Pertussis (Pinkbook)
- CDC – Manual for the Surveillance of Vaccine-Preventable Diseases
- CDC – Pertussis Frequently Asked Questions
- Effectiveness of pertussis vaccines–science vs. lies
- CDC – Coughing up the Facts on Pertussis: Emerging Trends and Vaccine Recommendations
- Study – The History of Pertussis (Whooping Cough); 1906–2015: Facts, Myths, and Misconceptions
- Study – Geographic Clustering of Nonmedical Exemptions to School Immunization Requirements and Associations With Geographic Clustering of Pertussis
- Study – Parental refusal of pertussis vaccination is associated with an increased risk of pertussis infection in children.
- Study – Geospatial analysis of nonmedical vaccine exemptions and pertussis outbreaks in the United States
- The horrible consequences of seeking “natural” immunity: Naturopathy and Whooping Cough
- Whooping Cough Photos
- CDC – Whooping Cough: A True Story
- Beyond Anti-Vax: The Pertussis Problem
- Whooping Cough Can Happen to You or Your Baby
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