The whooping cough epidemichas ended

Presumably, the whooping cough epidemic that started in the early summer of 2019 has now ended owing to the measures introduced to curb the spreading of COVID-19.

In 2019, a whooping cough epidemic affected Denmark and the epidemic continued until the spring of 2020. This is evident from the annual whooping cough figures from Statens Serum Institut (SSI).

A total of 3,691 cases of whooping cough were detected in 2019, compared with 1,023 cases in 2018 and 1,064 cases in 2017. In the latest previous whooping cough epidemic in 2016, a total of 2,089 cases were detected.

Most cases on Funen and in North Zealand

The annual figures show that in 2019, the highest number of cases was detected on Funen. Here, a total of 735 cases were detected. Furthermore, Funen recorded the highest incidence per 100,000 inhabitants of any area. The area recording the second highest number of cases was East Jutland with 611 cases. North Zealand registered 466 cases, but had the second highest incidence per 100,000 inhabitants (100.5), whereas North Jutland recorded the lowest incidence with 24.6 cases per 100,000 inhabitants.

Funen was also where the epidemic started in 2019, after which it spread to all of Denmark.

Drastic decline during the Danish lockdown

When the epidemic peaked in January 2020, a total of 874 cases were detected in a single month.

Subsequently, Denmark and the rest of the world were affected by the COVID-19 epidemic, which also affected the whooping cough epidemic. When comprehensive COVID-19 restrictions were introduced in March, a massive decline was seen in the number of people tested for whooping cough, and therefore also in the number of detected cases.

“We therefore presume that the general measures introduced to limit transmission in Denmark served to end the whooping cough epidemic”, notes Staff Specialist Peter Henrik Andersen, from the SSI.

Mainly infants and older schoolchildren were infected

All age groups were affected by whooping cough. Even so, a higher occurrence was observed among small children, unvaccinated infants and older schoolchildren. This was also seen among 35-55-year-olds, probably due to increased transmission and increased attention to the condition among parents to children with whooping cough.
A total of 299 cases were notified among children below two years of age in 2019. This included 116 (39%) non-vaccinated children, whereas 57 (19%) had received all three primary whooping cough vaccinations.

24,279 pregnant women vaccinated

Due to the whooping cough epidemic, in November 2019, the Danish Government introduced a free whooping cough vaccination offer for all pregnant women in their second and third trimester. This offer was subsequently extended repeatedly.

From 1 November 2019 to 22 June 2020, a total of 24,279 pregnant women have accepted the offer.