Cases of whooping cough have increased throughout the summer and August’s total of 439 cases was four times higher than normal. That figure only takes into account cases confirmed through lab testing.

Normally, the number of cases registered within a month is around 100.

“It’s well known that whooping cough appears as epidemics in intervals of three to five years. The last time we had an epidemic was in 2019-2020,” SSI head of department Peter Henrik Andersen said in a statement.

The epidemics typically last between six months and a year, he said.

Pregnant women are currently offered free vaccination against whooping cough, a single-dose injection at GP clinics intended to protect newborn infants during their early months until they can receive the vaccination themselves.

READ ALSO: Denmark reinstates free whooping cough vaccine during pregnancy

Denmark’s child vaccination programme includes jabs against the disease, but it is not given until the child is a few months old, with doses at 3, 5 and 12 months.

Whooping cough (kighoste in Danish) is caused by a bacteria, Bordetella pertussis. The time between infection and the onset of symptoms is around 5 to 15 days.

Both children and adults can be infected with the disease, but it is most dangerous for infants, according to the Danish infectious disease control agency SSI. 

Symptoms initially resemble a cold and light cough lasting around two weeks, before more severe and dry coughing fits begin. The dry coughing can last for as long as 10 weeks.

Small children can suffer up to 30-40 coughing fits per day as a result of the disease.

The infection can be dangerous for small children due to their narrower airways, in which hardened mucus can collect and cause breathing difficulties.

Long coughing fits can also result in the child not taking in sufficient oxygen.

Six infants have died of whooping cough in Denmark since 1995, according to official figures.