I’ve had a cough for a couple of weeks now. It comes and goes during the day, and makes it harder to get to sleep. It’s mainly been annoying. But recently it’s been getting worse and waking me (and my partner) up several times at night. So my partner finally persuaded me to go to Urgent Care.
It’s not the first time I’ve had a cough like this – I had bronchitis several times in my teens and early twenties, and it produced the exact same cough. But I was surprised and dismayed to learn that there is a significant chance that this time I actually have pertussis (whooping cough).
I’ve always associated pertussis with young children – it’s firmly in the “childhood disease for which there is a vaccine” category in my head. In very young children – particularly infants who have not been vaccinated – pertussis infection is frighteningly likely to lead to hospitalization, severe complications or (rarely) death.
What I didn’t know is that pertussis is increasingly more common in adults and teens – particularly in a hotbed of vaccine exemption like Boulder, CO, where I live now. The local vaccination rate dropped below herd immunity levels years ago, and Boulder County (along with many other U.S. cities) experienced an epidemic-level outbreak of pertussis back in 2012 and 2013.
It turns out that pertussis is still in Boulder. And adults are getting it. It’s not likely to kill me or put me in the hospital, but it is extremely unpleasant. And other adults like me who don’t realize what they have until they’ve already been contagious for weeks, are major sources of infection for more vulnerable populations.
Here is what I have learned about pertussis in the past 24 hours:
1) Pertussis is often missed in adults. A case of pertussis starts out looking exactly like the common cold, and is particularly difficult to distinguish symptomatically from other common respiratory infections. It can take a few weeks for the infection to progress from coldlike symptoms to severe cough. Many adults who contract pertussis never exhibit a “whooping” cough or experience any severe symptoms at all – so the true number of cases of pertussis may be somewhat higher than what’s reported to state and national public health agencies.
2) Adults are major spreaders of pertussis, in particular because they are harder to diagnose, and because we are often well through the most contagious period of the disease (the first two-three weeks) before we seek medical help and obtain a diagnosis – if we ever do at all. Finally, adults are less likely than children to have been recently vaccinated (see #7).
By the way, pertussis is *extremely* contagious. In a household where no one has current immunity, everyone will get it.
3) The coughing from pertussis can last three *months*. At its mildest, it’s ‘just a cough’. At its worst, the coughing can be so severe that it makes you vomit and/or experience sleep loss, cracked ribs, severe headaches and exhaustion. It sucks. It sucks a whole lot. You can get prescription drugs to treat it, but they make you drowsy; so during the day you have only cough drops and humidifiers and hot tea with honey to help.
4) You may never know with any certainty whether you actually had pertussis or not. No diagnostic test is 100% accurate. Pertussis testing is quite expensive, and kids always get priority over adults. Currently, your chance of getting a false negative result on a pertussis culture or PCR test increases over the course of the infection, because there are fewer and fewer bacteria in your mucus to detect1. Tests are also done by humans and subject to human error (contamination, etc.). So the benefit of testing may not outweigh the cost. Healthcare providers will probably assume you have pertussis AND other common respiratory bugs and treat you for all of them at once.
5) The best way to protect the most vulnerable populations isn’t early treatment or better diagnosis. It’s just not feasible to forcibly test everyone with cold symptoms early in their disease, nor is it in our best interest to blanket everyone with cold symptoms with the antibiotics we use to treat pertussis. We’d end up giving a lot of people antibiotics they don’t need, and accelerating the evolution of antibiotic resistant bacteria that will only come back to hurt us more.
So we will inevitably miss a lot of cases of pertussis in adults. The best way to protect ourselves and our loved ones from suffering from pertussis is prevention, through vaccination.
6) OTC cough meds are no more effective than placebo at reducing the duration of a cough.2,3
7) The immunity you acquire from pertussis vaccination or from contracting pertussis infection wanes over time. You need a booster every couple of years to maintain significant immunity to pertussis. If you spend a lot of time around young children or around adults susceptible to respiratory infection, you definitely need a regular booster.
8) Immunity isn’t the only benefit from vaccination. Vaccinated people not only less likely to get infected with pertussis, they’re likely to experience less severe symptoms than the unvaccinated.
9) If you get the right antibiotics within the first two or three weeks of illness, you stand a chance at reducing the duration of symptoms. After that, antibiotics will reduce your contagiousness, but may have no effect on the duration of your cough.
Featured image: The Flatirons in winter, Boulder, CO. CC BY-SA 2.5 Wikimedia Commons https://en.wikipedia.org/wiki/File:Flatirons_Winter_Sunrise_edit_2.jpg