Corticosteroids, a class of drugs that lowers inflammation, may be an effective treatment for children who develop a rare but serious condition after COVID-19 infection, according to a study.

All the 614 children in the study, published in the New England Journal of Medicine, developed a serious disorder following COVID-19 infection.

The disorder, called multi-system inflammatory syndrome in children (MIS-C), is thought to affect one in 50,000 children infected with the SARS-CoV-2 virus.

The illness generally occurs two to six weeks after the infection. It affects children of all ages but is more common in older children and teenagers.

The researchers from Imperial College London, UK, noted that the disorder is characterised by persistent high fever, often accompanied by abdominal pain, vomiting, red eyes and red rash.

According to the researchers, most global reports suggest a fatality of two to four per cent associated with the disorder.

However, an important concern has been that some affected children have developed inflammation of their arteries that supply the heart with blood, resulting in widening of these arteries, they said.

The study “suggests that steroids may be a cheaper and more available alternative to immunoglobulin,” said Elizabeth Whittaker, one of the authors of the study from Imperial College.

“Corticosteroids are cheap and available worldwide whereas immunoglobulin is expensive, and there is a worldwide shortage of it. This is a particular problem in many low and middle-income countries,” she added.

The researchers investigated two initial treatments for this condition: a type of steroid called corticosteroids, such as methylprednisolone, and antibody treatment called immunoglobulin.

The antibodies come from human blood and have been shown to reduce inflammation in the body.

The study also compared initial treatment with steroids together with immunoglobulin.

The research involved hundreds of doctors worldwide uploading information about patient outcomes onto an online database.

All three treatments — immunoglobulin, immunoglobulin combined with corticosteroids and corticosteroids alone — resulted in a more rapid decrease of inflammation.

There were no clear differences between the three treatments in rate of recovery from organ failure or progression to organ failure, the researchers noted.

They noted that the number of fatal cases (2 per cent) was too low to enable comparison between treatments, but death was included in a combined assessment with organ failure, which found no significant differences between the three treatments.

The analysis was then restricted to the 80 per cent of children who met the World Health Organization’s criteria for MIS-C.

There was evidence of a lower rate of organ failure or death at two days in those receiving steroids alone as initial treatment, compared to immunoglobulin alone.

However, the authors stress there is insufficient data to establish that all three treatments are equivalent in preventing coronary artery aneurysms.

Around six per cent of children in the study suffered a coronary artery aneurysm, they added.

“Our finding, that treatments with immunoglobulin, steroids or a combination of both agents all result in more rapid resolution of inflammation will be of great value to paediatricians worldwide in their treatment of children with this new disorder,” said Professor Michael Levin, from the Department of Infectious Disease at Imperial, who led the study.

As immunoglobulin is unavailable or in short supply in many countries, and is expensive, the findings may provide some reassurance for those who only have access to corticosteroids,” Levin added.