What’s behind the sudden rise of whooping cough in Czechia?

Whooping cough has seen a dramatic increase this year in Czechia – at the last count there have been 1,666 confirmed cases since the start of the year, more than in the last four years combined. Over the last two decades, the only year that saw a greater number of infections was 2014, when there were over 2,500. But experts say that on the current trajectory, it is likely that the total number of cases this year will far surpass that. I spoke to Jana Kamanová from the Institute of Microbiology at the Czech Academy of Sciences to find out what is behind the sudden rise in infections.

There’s been quite a rise in the number of cases of whooping cough this year – more than the last four years combined and we’re only in March. But the whooping cough vaccination is compulsory in Czechia, so what’s responsible for this meteoric rise?

Jana Kamanová | Photo: Matěj Skalický,  Czech Radio/Vinohradská 12

“The situation is complex. One of the problems is that we had covid restrictions. Usually pertussis (whooping cough) would circulate throughout our population and induce immunity. But when we had covid restrictions in place, the circulation really decreased, so now people don’t have natural immunity and they are getting infected.

“But this is only half of the story. The rest of the story is that although we do have compulsory vaccination, the vaccine doesn’t protect against infection, it protects against symptoms. So if you get vaccinated, you do not develop severe whooping cough, but you still can get infected by the bacteria Bordetella pertussis which causes the illness.”

I read somewhere that the older vaccine against whooping cough, the one used before 2007, is more effective at protecting against whooping cough and lasts longer. Why was there a switch to a less effective vaccine?

Photo: Semevent,  Pixabay,  Pixabay License

“That’s perfectly true. The more effective vaccine is more reactogenic, so it induces a stronger and different kind of immune response which protects us better. But it also induces side effects. So the scientists at that time thought maybe we should develop something less reactogenic. That was one reason.

“The second reason was that it was a vaccine made from the whole bacteria, and basically its production at that time was not very reproducible, so we were getting a lot of batch-to-batch variation. So scientists were thinking maybe if we switch to something more refined, it would be more reproducible. But it’s true that the previous vaccine was a little bit better than this one.”

If you have been vaccinated against whooping cough with the older vaccine, do you still need to get re-vaccinated?

“I would say that it’s advisable to get re-vaccinated if you are pregnant or if you are in a high-risk group like seniors or people with compromised immunity. Currently, doctors would really recommend that pregnant women in their third trimester get vaccinated, because this can really protect their newborn babies who are not yet vaccinated.”

Are there any other groups that are at risk of serious complications with whooping cough?

Photo: Filip Jandourek,  Czech Radio

“I would say it’s only really the small newborn babies, because the vaccination which is compulsory in the Czech Republic is a several-dose scheme. Babies only get protected roughly two weeks after their second dose in the fourth month of their lives, and they are a really high-risk population – for infants who have not yet been vaccinated, pertussis can be really lethal. Before the vaccine was developed, they were the ones most affected and there was a high number of deaths. So the only thing that can protect them before that is vaccination of their mothers during pregnancy.

“And the other at-risk group is older people. We did have two or three deaths of older people in the past year, so they are another risk group.”