Parapertussis – a relative of pertussis?

Why is parapertussis important?

There are two main reasons why I decided to write this post.
A. Parapertussis causes an infectious disease. It is not as severe a disease as whooping cough (also referred to as the 100-day cough), but it can still lead to a moderate-severe infectious illness and it’s important to be familiar with it.
B. Sometimes, when testing for pertussis using a PCR swab test, parapertussis is tested as well. And if the results indicate the person is positive for parapertussis, they don’t always know what needs to be done next. This post may provide some help.

What is parapertussis?

Parapertussis infection is caused by a bacteria called Bordetella parapertussis. This infection, too, has a tendency to present in defined outbreaks.

How does an infection caused by this bacteria manifest?

The main clinical manifestation is a nagging cough. The cough is not as severe as the one witnessed in whooping cough. The infection is more significant in babies, elders, and people with underlying medical conditions.

Does the pertussis vaccine protect against parapertussis infection as well?

There is no vaccine for parapertussis.
Is a person who was vaccinated for pertussis, somewhat protected from the parapertussis infection? It sounds sensible to think so, but there is no scientific evidence for it in the medical literature.
So practically speaking, no – there is no vaccine for parapertussis.

Does a person infected with parapertussis need to be treated?

Early treatment can shorten the duration of the illness, similarly to the pertussis infection. Additionally, our textbooks emphasize the need to consider treatment when the person infected is at high risk of developing severe illness, for example younger infants, elders and people who are immune deficient.
The illness can be treated with the same antibiotics as pertussis – Azithromycin, given for a duration of 5 days. You can read more about the treatment here.

Do people who have been exposed to a person with parapertussis need to be treated?

Interestingly, there is an ongoing debate about this among medical professionals and some of the medical textbooks do not recommend prophylactic treatment for exposed individuals. Therefore, prophylactic antibiotics are typically not recommended. However, I would suggest you refer to your national health guidelines for more information, as guidelines may vary depending on where you are.
It is important that people with parapertussis avoid contact with other individuals (especially with individuals at high risk, as I mentioned previously), until they have completed all 5 days of antibiotic treatment.

To wrap it up – if your PCR swab test indicates you are positive for parapertussis but negative for pertussis, contact your doctor, show him/her this post, and make a joint decision as to how you should proceed with management.

Good luck!