Health experts are looking into reports that a coronavirus-related syndrome among children may be emerging in the UK, NHS England’s national medical director has said.

Professor Stephen Powis said it was “too early to say” whether there is a link between the Kawasaki-like disease and coronavirus, but chief medical officer Prof Chris Whitty said it was “entirely plausible”.

They have instructed medical experts to look into the potential link as a “matter of urgency”.

It comes after the UK Paediatric Intensive Care Society (Pics) tweeted an alert it said was from NHS England which says in 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”.

NHS England confirmed it had shared the warning through its incident teams to clinical commissioning groups and hospital trusts.

The alert said the effects had been seen in children both with and without coronavirus but there was evidence that some patients had had coronavirus previously.

Health Secretary Matt Hancock said he was “very worried” by the reports.

Speaking at the daily Downing Street press conference, Prof Powis said: “We have become aware in the last few days of reports of severe illness in children which might be a Kawasaki-like disease.

“Both Chris (Whitty) and I are aware of that, and we have asked our experts, I have asked the national clinical director for children and young people to look into this as a matter of urgency.”

He urged parents who are worried about a child who is sick and not recovering to seek medical help.

Prof Whitty added: “This is a very rare situation but I think it is entirely plausible that this is caused by this virus, at least in some cases.

“Because we know that in adults who of course have much more disease than children do, big problems are caused by an inflammatory process and this looks rather like an inflammatory process, a rather different one.

“Therefore, given that we have got a new presentation of this at a time with a new disease, the possibility – it is not a definite, we need to look for other causes as well – but the possibility that there is a link is certainly plausible.”

According to the alert, which was originally shared with GPs in north London, children affected display signs similar to toxic shock syndrome (TSS), a severe illness associated with infections, and have blood markers in line with severe Covid-19 in children.

They may also have abdominal pain and symptoms of inflammation around the heart.

The alert says: “There is a growing concern that a Sars CoV-2 (Covid-19) related inflammatory syndrome is emerging in children in the UK, or that there may be another, as yet unidentified, infectious pathogen associated with these cases.”

The alert talks about atypical Kawasaki disease, a condition that mainly affects children under the age of five.

Symptoms include a high temperature that lasts for five days or more, often with a rash and/or swollen glands in the neck.

NHS England stressed there was no confirmed connection between Kawasaki-related diseases and Covid-19.

Professor Simon Kenny, the NHS’s national clinical director for children and young people, said: “Thankfully Kawasaki-like diseases are very rare, as currently are serious complications in children related to Covid-19, but it is important that clinicians are made aware of any potential emerging links so that they are able to give children and young people the right care fast.

“The advice to parents remains the same: if you are worried about your child for whatever reason, contact NHS 111 or your family doctor for urgent advice, or 999 in an emergency, and if a professional tells you to go to hospital, please go to hospital.”

Professor Russell Viner, president of the Royal College of Paediatrics and Child Health (RCPCH), said parents should be reassured that children are unlikely to be seriously ill with Covid-19.

He said: “We already know that a very small number of children can become severely ill with Covid-19 but this is very rare – evidence from throughout the world shows us that children appear to be the part of the population least affected by this infection.

“New diseases may present in ways that surprise us, and clinicians need to be made aware of any emerging evidence of particular symptoms or of underlying conditions which could make a patient more vulnerable to the virus.

“However, our advice remains the same: parents should be reassured that children are unlikely to be seriously ill with Covid-19 but if they are concerned about their children’s health for any reason, they should seek help from a health professional.”

According to the NHS, children are contracting Covid-19 at the same rate as adults but are suffering less severe symptoms on the whole.

However, children have died, including 13-year-old Ismail Mohamed Abdulwahab, from Brixton, south London, who died in King’s College Hospital at the end of March.

The latest figures for hospital deaths of patients testing positive for Covid-19 in England show that up to 5pm on April 25 there had been nine deaths between the ages of 0 and 19.

This represents 0.05% of all hospital deaths in England.

In Scotland, no Covid-19 deaths had been registered by April 19 for people aged 0-14. In Northern Ireland, no Covid-19 deaths had been registered by April 17 for people aged 0-14.