Children who develop a rare Kawasaki-like inflammatory syndrome after catching Covid recover within three months, a study has found.
While coronavirus poses a tiny risk of death or serious illness to youngsters, there were concerns over reports of some being struck down by multi-system inflammatory syndrome (MIS-C).
Medics were concerned about its long-term impact because it is a new condition, only seen in children in the weeks after getting infected.
Now University of Pennsylvania researchers say all affected children appear to fully recover within three months.
Their study of 120 children — half of whom were hospitalised with MIS-C — found they all had normal heart function within the space of a week.
However, they admitted further studies were needed to rule out any future complications that go beyond the scope of their research.
MIS-C, also known as paediatric inflammatory multisystem syndrome (PIMS), causes swelling throughout the body, including around vital organs such as the heart.
It can cause symptoms similar to Kawasaki disease, including a high temperature, a rash, tiredness and stomach pain. In rare cases, some children may require intensive care.
It is triggered by an overreaction in the immune system to fight off a Covid infection and sees the body attack healthy cells.
Researchers estimate it affects roughly one in 3,000 people aged 21 or younger who get infected with the virus.
The University of Pennsylvania graphs show different measurements of heart performance among MIS-C patients (red line) and those who did not have Covid or heart problems (blue line). It shows that overall heart strain, which measures whether the heart is deformed (graph A), right ventricular strain (graph B), left atrial strain (graph C) and longitudinal early diastolic strain (graph D) were worse among those MIS-C patients in the weeks after they were admitted, but had returned to normal between one and 12 weeks later
Bertie Brown was admitted to Worcestershire Royal hospital in March 2020 on his second birthday after being struck down by multi-system inflammatory syndrome (MIS-C), which caused a fever and rash across his body
Dr Anirban Banerjee, a paediatrician and senior author of the study, published in the the Journal of the American Heart Association, said: ‘Recovery among these children was excellent.
‘These results have important implications for our health care teams managing care for children with MIS-C.
‘Our findings may also provide guidance for a gradual return to playing sports after cardiac clearance three to four months later.’
Researchers looked at 60 children with MIS-C who were admitted to two hospitals in Philadelphia between April 2020 and January 2021.
WHAT IS COVID-RELATED MULTISYSTEM INFLAMMATORY SYNDROME (MIS-C)?
MIS-C — also known as paediatric inflammatory multisystem syndrome (PIMS) — causes swelling throughout the body, which is one way the immune system fights off infection, injury and disease.
But among those with MIS-C, the immune system over-reacts and affects other parts of the body.
Most children and young people who develop Covid have no or very mild symptoms, but some go on to develop MIS-C in the weeks after their infection.
There is no specific test to diagnose MIS-C so doctors examine symptoms and take a blood sample to examine inflammation levels.
Its symptoms include a rash, tiredness and weakness, stomach pain. red and cracked lips, swollen hands and feet, peeling skin on the hands and feet, a headache, red eyes, muscle aches and pains, diarrhoea and vomiting, swollen neck glands and unexpected irritability.
It is treated through intravenous immunoglobulin (IVIG), which is a drip containing antibodies that fight off infection.
MIS-C patients may also receive corticosteroids – tablets or liquid taken by mouth that calm down the immune system.
Source: Great Ormond Street
The children, who were mostly boys and aged 10 on average, were treated with intravenous immunoglobulin — an antibody treatment that helps fight off infection — or corticosteroids, which calm down the immune system.
The team examined the youngsters medical records and heart scans.
And they monitored their recovery over the subsequent three to four months.
They compared the findings to a control group of 60 children who did not have Covid or heart problems.
They found that all the MIS-C patients’ heart function improved quickly within the first week of their admission and continued to improve.
And even patients with ‘significant cardiac abnormalities’ saw their changes resolve within three months.
Seven per cent of the hospitalised children had some heart malfunction when first admitted, but this had disappeared three months later.
Eight in 10 patients lost some contractile function — the ability of the heart to contract and pump blood — when they were most unwell, but three to four months later this had also returned to normal.
And the condition did not cause any long-lasting problems in the coronary arteries, which are responsible for supplying blood to the heart.
After doing a strain test of the participant’s hearts three months later — which detects whether an area of the heart is deformed or functioning differently — the team concluded there was no heart dysfunction three months after they were hospitalised.
But the researchers warned MIS-C and Covid are still new illnesses, so it is yet to be determined if sufferers’ hearts have any problems beyond four months after they were diagnosed with heart problems.
It is different to myocarditis, another very rare heart inflammation condition which was spotted in up to one in 12,300 youngsters after getting vaccinated and one in 2,200 young people who catch Covid.
Dr Kevin Friedman, a member of the American Heart Association’s council, said: ‘This study provides additional evidence that myocardial involvement is transient and may not lead to long-term abnormalities in left ventricular diastolic or systolic function.
‘Although cardiac involvement in the acute stage of illness is common, it is reassuring that all patients recovered normal cardiac function within about one week.
‘This data tells us that, fortunately, lasting heart injury is very uncommon in MIS-C.
‘Even in those patients with significant cardiac abnormalities in the acute phase of illness, these changes resolved by three to four months.’