Just 0.005% of children or young people who catch the coronavirus die as a result of the infection, research suggests.
Even among adults, early research suggests the coronavirus is mild in four out of five cases. In severe incidences, however, the infection can trigger the disease called COVID-19.
Deaths among children were known to be "rare", however, a high rate of asymptomatic infections made the exact risk "challenging" to quantify.
To learn more, scientists from the Bristol Royal Hospital for Children analysed the number of under 18-year-olds who died after a positive coronavirus test between March 2020 and February 2021.
A "clinical review" then determined whether the child or young person died of the coronavirus itself or "an alternative cause" with a "coincidental" infection.
Results – which have not yet been published in a peer-reviewed journal – suggest 99.995% of the children or young people who caught the coronavirus survived.
During the pandemic, the National Child Mortality Database has been linked to Public Health England coronavirus testing data.
The Bristol scientists found 3,105 under 18-year-olds died from any cause during the first year of the infectious outbreak in England. Of these fatalities, 25 were linked to the coronavirus itself.
"99.995% of CYP [children and young people] with a positive [coronavirus] test survived," wrote the scientists.
Based on the more than 12 million CYP living in England, 25 coronavirus deaths equates to a mortality rate of two per 1 million patients.
As with adults, fatalities were found to become more common with age, disproportionately affecting CYP over 10 years old. Those with a pre-existing medical condition, or an Asian or Black ethnicity, are also more at risk, the results suggest.
To better understand COVID risk factors among CYP, a separate study by the University of Liverpool analysed children who were admitted to hospital with a confirmed coronavirus infection or COVID-related inflammatory syndrome between 1 January 2020 and 21 May 2021.
Early in the pandemic, NHS doctors were told to look out for signs of "multi-system inflammation" after intensive care units in London saw eight children with unusual symptoms, some of whom tested positive for the coronavirus.
The inflammatory syndrome has been likened to atypical Kawasaki disease; a rare condition that usually affects children under five and causes blood vessels to become inflamed, leading to heart complications in around a quarter (25%) of patients. Left untreated, it can be fatal in 2% to 3% of cases.
The Liverpool scientists found babies were 63% more likely to be admitted to critical care with the coronavirus or its inflammatory syndrome as children aged one to four. Infants were also over twice as likely to die.
The risk of death then more than doubled among the children older than 10, compared to their one to four-year-old counterparts.
Perhaps unsurprisingly, pre-existing medical conditions – aside from asthma – were linked to an increased risk of complications.
One so-called "comorbidity" raised the risk of requiring critical care by 49%. Two underlying conditions more than doubled the odds, while three or more pre-existing ailments nearly tripled the risk.
A CYP's death risk more than doubled with one comorbidity, while at least two pre-existing medical conditions quadrupled the odds, particularly if the underlying disease affected the heart or brain.
Medical conditions aside, obesity was also linked to an increased risk of severe coronavirus complications or death.
Watch: Coronavirus can cause inflammatory syndrome in children
Speaking of the results, Professor Russell Viner – from University College London (UCL) – said: "Even 10 times a tiny risk is still a very, very tiny risk. For all children and young people, the risk is still low."
Professor Lorna Fraser – from the University of York – agreed, adding: "It's important to remember the risks are very low for all children and young people. These risks were still very small compared to risks seen in adults".
The risk factors that raise a child's odds of severe complications are "broadly consistent" with those for older people.
"These conditions were also risk factors for other illnesses leading to admission to intensive care, but to a lesser degree than for COVID-19," added Dr Joseph Ward, from UCL.
A third and final study, by UCL, produced similar results.
In adults, the coronavirus is known to cause more severe complications in men. Among children, however, "there was no association by sex", added the UCL team.
The results of the three studies will be submitted to the UK's Joint Committee on Vaccination and Immunisation, the Department for Health and Social Care, and the World Health Organization.
These will reportedly help to inform vaccine and shielding policies for people under 18 years old.
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