LONDON • People under 20 are around half as susceptible to the coronavirus as people aged 20 or above, according to research published yesterday.
Clinical symptoms of Covid-19 appear in only about a fifth of infections in children and teenagers.
The research, a modelling study using data from 32 locations in China, Italy, Japan, Singapore, Canada and South Korea, found that, by contrast, Covid-19 symptoms appear in 69 per cent of infections in people aged 70 or older.
The findings suggest that school closures – introduced in many countries as part of lockdowns aimed at controlling the pandemic – are likely to have a limited impact on the transmission of the disease, the researchers said.
Published in the journal Nature Medicine, the study compared the effect of school closures on simulated outbreaks of flu – which is known to spread swiftly in children – and of Covid-19.
“For Covid-19, there was much less of an effect of school closures,” said infectious disease modeller Rosalind Eggo, of the London School of Hygiene and Tropical Medicine, who co-led the study.
She added, however, that the findings come from simulated outbreaks and need to be reinforced with real-world research.
Using demographic data from the six countries, as well as from six studies on estimated Covid-19 infection rates and symptom severity across different age groups, the model showed that people under 20 are about half as susceptible to Covid-19 as people over 20.
Among 10-year-olds to 19-year-olds, only 21 per cent of those infected had clinical symptoms.
The researchers also simulated Covid-19 epidemics in 146 capital cities around the world and found that the total expected number of clinical cases varied with the median age.
“The age structure of a population can have a significant impact,” said Dr Nicholas Davies, who co-led the work.
“Countries with more young people may experience a lower burden of Covid-19.”
The findings suggest that school closures – introduced in many countries as part of lockdowns aimed at controlling the pandemic – are likely to have a limited impact on the transmission of the disease.
Numerous studies have shown that symptoms are likely to be more severe the older the patient is.
There have been relatively few confirmed cases in children, though whether or not this is down to fewer young people catching the virus or proportionally fewer showing Covid-19 symptoms when they are infected is not clear.
A variety of explanations has been offered, including that children are more frequently exposed to coronaviruses and therefore better equipped to fight off Covid-19 infection.
REUTERS, AGENCE FRANCE-PRESSE