In the spring, international reports came in that children who tested positive for covid-19 later fell ill - and in some cases died - of a serious multi-inflammatory condition. Initially, the condition was compared with the childhood disease Kawasaki, which affects more than 50 children in Sweden each year.

- But what we see now is something new, even though there are several similarities with Kawasaki's disease, says Jonas F Ludvigsson, pediatrician in Örebro and professor of epidemiology at Karolinska Institutet.

The new disease, which has been named multi-inflammatory syndrome (MIS), mainly affects children who are a couple of years old and have, among other things, a greater impact on the heart, Jonas F Ludvigsson explains.

- In that way, MIS is probably worse. I have seen children with very strong heart effects, much more than at Kawasaki.

- It is a dangerous disease insofar as many children become seriously ill and require treatment. Then it is still the case that deaths are extremely rare.

Tio iva-fall

In mid-May, the Swedish Pediatric Rheumatology Association became aware of four suspected MIS cases. Today, the figure is around 50 cases. Just over ten of the children have received intensive care and another three have received treatment with an artificial lung outside the body. With some exceptions, the children have otherwise been healthy.

The condition is life-threatening, but according to Lotta Nordenhäll who is chief physician at Sachsska Children's and Adolescent Hospital in Stockholm and chairman of the Swedish Pediatric Rheumatology Association, no child has died as a result of the disease in Sweden.

- We have chosen to treat very aggressively and managed to turn all cases around. says Lotta Nordenhäll.

Strong connection with covid-19

The connection between covid-19 and hyperinflammation has previously been described by Italian researchers and the WHO and the Swedish Public Health Agency are also following the development. Jonas F Ludvigsson says that he feels quite confident that it is covid-19 that is the triggering factor.

- But not all children have been tested positive for covid-19, which I think is due to the fact that not everyone seems to develop antibodies after an infection.

Jonas F Ludvigsson himself has dealt with two to three suspected cases of MIS during the spring. All new conditions are worrying, he says, but as long as Sweden is not faced with a strong second wave this autumn, the cases are likely to decrease.

- As a parent, I would not worry about MIS.