Whooping cough on the rise in Sweden [Advocacy Lab Content]

Whooping cough incidence in Sweden is on the rise. The Swedish chief epidemiologist advises parents to keep their babies away from people with cold symptoms – similar trends are now seen in other parts of Europe.

Whooping cough – or pertussis – is an endemic disease that can cause severe illness in all ages but is most dangerous for newborns and infants under one year.

The Public Health Agency of Sweden recently warned that cases are rising across Sweden after remaining at very low levels during 2020-2023.

“We had almost no cases during the COVID-19 pandemic. But this year, 241 cases have been reported,” Magnus Gisslén, Sweden’s state epidemiologist and an infectious diseases doctor working for the agency, told Euractiv.

Of these cases, 28 were babies under one year of age, 84 were children from one to 19 years old, and the rest were aged 20 and over. No deaths were reported in Sweden in 2024; 19 were reported in EU/EEA.

Very contagious

Whooping cough spreads through the air, is highly contagious and initially shows symptoms similar to a common cold.

Magnus Gisslén believes that the total number of cases in Sweden is much higher than reported, as many cases may remain unrecognised or may not be recorded.

He also expects the number of cases to continue rising during the summer season.

“This is a pattern typically observed in pertussis, with cases often peaking in late summer or early autumn. Cases can be expected to rise to levels seen before the pandemic, but could potentially also be higher, due to a decreased contribution to immunisation of natural boosting in the overall population,” he believes.

As babies could get seriously ill, Magnus Gisslén warns that: “Parents should not let their babies come close to people with coughs or colds outside the family; this is very important. Infants need to be protected.”

Vaccination ‘turn the tide’

Historically, the number of cases in Sweden has been much higher at times when there was no effective vaccine.

“When I was a young infectious diseases doctor in the late eighties and the nineties, it was very common to see children with severe pertussis, often ill for several months with complications such as pneumonia,” he told Euractiv.

At that period, the number of cases in Sweden could be as high as above 10,000 per year,” he added.

A national vaccination programme against whooping cough began in Sweden in 1953, and the number of infections fell to a low level. Cases rose again between 1979 when the so-called whole-cell pertussis vaccine was discontinued, and the introduction of a new and better vaccine in 1996.

The current outbreak is occurring despite the fact that 95 per cent of children in the country are vaccinated five times from the age of three months in accordance with the national childhood immunisation schedule.

“Today’s vaccine is effective against serious diseases and can prevent infections, but does not provide long-term protection against transmission. You can never vaccinate the bacteria away,” Gisslén said, adding that the level of immunity from infections and vaccinations is not lifelong and typically wanes after ten to fifteen years.

He also recommends that pregnant women get vaccinated after the 16th week of pregnancy, as the vaccine protects babies from the moment they are born.

If an infant is suspected of having whooping cough, prompt treatment is important to reduce the risk of serious illness, according to the Swedish Public Health Agency.

Prompt treatment

Babies exposed to the virus may need treatment even if they have no symptoms.

Pregnant women and family members with persistent coughs should also be tested and treated with antibiotics if they have whooping cough to reduce the risk of the baby being infected after birth.

According to a recent risk report from the ECDC, infants under the age of one had the highest incidence rate in 17 of the EU/EEA countries in 2023-2024, whereas adolescents (10-19 years old) were higher in six countries.

In 2023, the EU/EEA countries reported an increase in the number of cases of whopping cough, with 25,000 cases reported.

In 2024, however, the number registered so far has already reached 32,000 cases, according to the ECDC.

That may indicate an even higher or more rapid spread of infections than before the pandemic, as the similar number of cases was 34,468 in 2019.

[By Monica Kleja, edited by Vasiliki Angouridi, Brian Maguire | Euractiv’s Advocacy Lab]

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