None of the children who have suffered from a rare inflammatory syndrome caused by COVID-19 in the UK had long-term health problems before falling ill, doctors say.
Between 75 and 100 children are known to have developed the illness, which can cause symptoms similar to sepsis, since the beginning of April.
In adults, many of the coronavirus patients who become most seriously ill are those with other health problems, such as high blood pressure, diabetes or heart disease – dubbed ‘underlying health conditions’.
But all the children treated for this inflammatory disease so far had been healthy before they caught the coronavirus, according to Dr Liz Whittaker.
Dr Whittaker is a paediatrician at Imperial College Healthcare in London and has herself treated children with the illness, which has been likened to Kawasaki disease.
She said they are not showing signs of ‘typical’ COVID-19 infection and it was not obvious why some children were worse affected than others.
Children’s ethnicity does not appear to increase their risk of the serious illness, as it does for adults with COVID-19. Dr Whittaker hinted that a high proportion of ethnic minority children had been treated for the inflammatory syndrome, but said this so far seemed to be linked only to where the virus was spreading the most.
Children with the illness are usually taken to hospital with a high fever that has lasted a number of days and severe abdominal pain. The most seriously ill may develop sepsis-like symptoms such as rapid breathing and poor blood circulation
Dr Whittaker said: ‘To date, the children have not had underlying comorbidities [illnesses] that we have identified.
‘We are gathering that information through a surveillance study that [is] happening both in the UK and internationally, but so far there isn’t anything in particular that we can comment on from that perspective.’
The revelation suggests that there are no particular groups of children known to be at a higher risk of developing severe illness from coronavirus infection.
Scientists still don’t really understand how the virus affects young people and, according to one top paediatrician, fewer than 500 children have been hospitalised because of it in Britain since the outbreak began.
That compares to tens of thousands of adults, many of whom have died – 12 people under the age of 20 have died with COVID-19 in England so far, out of a total of 23,953.
Asked whether ethnicity had any bearing on a child’s chances of developing the syndrome – adults appear to be at higher risk if they are from Asian or black backgrounds – the doctors said this doesn’t appear to be the case.
There is known to have been a cluster of cases in South East London, which has a high proportion of non-white residents.
Dr Whittaker said: ‘The question about whether there’s an increased number of black and ethnic minority children affected… I still think that reflects where viral transmission is happening.
‘South East London, from an epidemiological perspective, has the highest rates of COVID-19 in the country. So I think that it’s not unsurprising that you then see a cluster in that part of London of this really extremely rare condition.
She added: ‘I’m also involved in the European surveillance mechanism and looking at a bigger cohort of 77 children, just as a first look… actually the majority of those children are Caucasian and with relevant proportions of black and Asian ethnicities.
‘I think it’s really important that we explore whether there’s a genetic predisposition, or an ethnic predisposition, to this condition but at the moment we don’t have enough evidence.’
So far, doctors seem only to be able to predict which children might develop severe complications once they are already in hospital.
Professor Michael Levin, an expert in international child health at Imperial College London, said there are signs in the blood that a child might end up in intensive care.
He said: ‘In the very short period of time that we’ve been trying to study this problem we have learnt that there are some markers in the blood that, if we measure them, they seem to predict which patients are going to do badly and need more support and more treatment.
‘Just knowing that does help us quickly know if a child is likely to need more support and more treatment…. We need to study this at much bigger numbers.’
Doctors yesterday revealed that dozens of children, most aged between five and 15 years old, have become seriously ill with the condition that seems to appear up to a month after catching the coronavirus.
They say it is extremely rare and does not appear to have directly killed anyone in Britain but can lead to intensive care for a small proportion of those who get it.
The illness has been likened to Kawasaki disease, a rare disorder which causes rashes and a red mouth and eyes.
At least 18 children in London have been diagnosed with it since doctors first started noticing the syndrome last month.
Most troubling experts is that the illness is almost definitely caused by COVID-19 in some way but scientists can’t prove it.
The young patients’ lungs are not affected by it – in adults the coronavirus’s main target is the lungs – and many test negative when they are swabbed for the disease.
All of the patients studied so far, however, have tested positive for COVID-19 antibodies, meaning they have been exposed to the virus in the past. Scientists now believe it could be the consequence of the immune system going haywire after it has fought off the coronavirus infection, causing a second illness weeks later.
The same illness has been seen in Italy and China and around 100 children are known to have been diagnosed with it in New York.
Speaking in a briefing on Wednesday, Dr Whittaker said: ‘There is likely an iceberg effect and we’re only seeing only the very, very sick children.’
She said the peak of admissions related to the illness appeared to have happened last week.
Explaining the disease, Dr Whittaker said: ‘These children are usually presenting when they’ve had a high fever for a few days.
‘A large proportion of them have had severe acute abdominal pain and diarrhoea and some have them have had the rash, red eyes and red lips.
‘A very small group of these children develop something we call shock, which is that small group of children for whom the heart is affected.
‘And those children become very unwell – they get cold hands and feet and they breathe very fast. Those are the group who absolutely need to be in an intensive care unit getting supportive care rapidly.
‘Most children seem to be very unwell for four or five days but then get better.’
It is not clear exactly how many children have needed intensive care for the Kawasaki-like syndrome, but a surveillance study has now begun in Britain and early results may be available next week.
Professor Russell Viner, the president of the Royal College of Paediatrics and Child Health, said knowing about the syndrome had not changed the ‘basic arithmatic’ of COVID-19.
He said: ‘In general, children get no symptoms or very mild symptoms. They rarely present to hospital.
‘In fact across the whole of the UK there’s been under 500 admissions to hospital for COVID-19.’
The experts described the illness as a ‘post-infectious phenomenon’ because it seems to appear weeks or even up to a month after the child caught the coronavirus.
And, unusually, it seems not to affect their lungs. COVID-19 is considered a respiratory infection in adults, meaning it focuses almost entirely on the lungs.
The Kawasaki-like syndrome being seen in children, however, seems to affect the heart in serious cases. It still causes a high fever, as in adults, but apparently not coughing or shortness of breath.
Dr Whittaker explained: ‘These children don’t have really bad lung disease. The adults that we’re mostly seeing on the wards are presenting with really bad breathing problems.
‘These children; their lungs aren’t affected… We know that some of these children have had their heart tissue affected, maybe we would find the virus in other parts of the body which are harder to access.’
She said this could account for why children appeared to be testing negative for COVID-19, despite having the syndrome.
Swab tests currently rely on collecting cells from the nose and throat and testing those to look for signs of infection in the airways.
Dr Whittaker added: ‘There is the possibility that we’re taking samples from the wrong place.’
The illness also differs from COVID-19 in adults in that the children who have developed it have not had underlying health conditions.
The illness first came to public attention when NHS England in April circulated a warning urging doctors to look out for the condition.
In an alert sent to GPs on April 27, health chiefs said: ‘There is growing concern that a [COVID-19] related inflammatory syndrome is emerging in children in the UK.
‘Over the last three weeks there has been an apparent rise in the number of children of all ages presenting with a multi-system inflammatory state requiring intensive care across London and also in other regions of the UK.’
Health Secretary Matt Hancock at the time said he was ‘very worried’ by the reports.
But experts say learning about the illness does not mean children are at any more risk from the coronavirus, and it does not mean they will be at risk when schools go back.
Schools will not continue to open if there is a risk of mass transmission of the virus, and cases are ‘exceptionally rare’, only beginning to appear after the darkest days of Britain’s outbreak when huge numbers of people were getting infected and dying of the virus.
Professor Viner added: ‘Fears about this syndrome shouldn’t stop parents letting their children exit the lockdown.
‘But parents do need to do is have some knowledge and have some understanding so they can recognise this and seek help very early.’