Christmas hugs for Granny? Here’s what the science says about the risk
As Christmas approaches, many grandparents will be anticipating seeing their grandchildren for the first time in several months, as restrictions are relaxed to allow families to come together.
But although hugging will be allowed under the five day festive armistice, is it actually safe to be close to youngsters?
Professor Chris Whtty has warned that just because physical contact between people from three different households will be legal this Christmas, it does not mean it is safe.
“Would I encourage someone to hug and kiss their elderly relatives?” he said last month. “No I would not… if you want them to survive to be hugged again.”
So what are the dangers of being around children this Christmas? Here is the latest evidence:
Are children more likely to spread the virus?
Surprisingly, the answer to this appears to be no. While children are normally super-spreaders of contagious diseases, coronavirus seems to be different.
The answer to this may lie in the fact children are both less likely to catch the virus, and more likely to be asymptomatic even if they do become infected, and so less likely to pass it on.
In a UK study of 2–15-year-olds, up to 50 per cent of infected children developed no symptoms. For adults, around one in five have no symptoms.
A worldwide study published in Nature in October also found that schools are not hot-spots for coronavirus infections. Cases of Covid-19 did not surge when schools and day-care centres reopened after pandemic lockdowns eased.
Data on school outbreaks in England have shown it is often adult teachers who were the first to be infected. Out of the 30 confirmed school outbreaks in June involved transmission between staff members, and only two involved student-to-student spread.
Is there a difference between age groups?
The risk from children appears to rise with age, with primary school youngsters posing less danger than those at secondary school.
A study of US pupils showed the rate of infection is twice as high in children aged 12–17 years as it is among 5 to 11-year-olds.
Studies have also shown that once if infected, young children under five, are less likely to pass the virus on to others than older children.
Although children appear to have similar viral loads to adults if they do become infected, they are still less likely to transmit. Researchers have suggested that it could be because they have smaller lungs, and so are less able to project infectious aerosols than are adults.
However children at secondary school appear to be a bigger transmission risk. The most recent data from the ONS show that positivity rates are currently highest among secondary school age children.
An analysis of German schools, by the Robert Koch Institute, found infections were less common in children aged 6–10 years than in older children and adults working at the schools.
Are people living with children at greater risk?
Recent research from the London School of Hygiene and Tropical Medicine (LSHTM) and the University of Oxford, found adults living with very young or primary-school-age children had no increased risk of Covid-19 infection or a related hospital admission.
In fact, they were about 25 per cent less likely to die of Covid-19 than people living without children, which the researchers think may be linked to healthier living habits previously identified in those who care for children.
However people living with secondary-school-age children had an eight per cent increased risk of a Covid-19 infection, but no increased risk of hospitalisation.
Why are children protected?
There is growing evidence that youngsters may be protected because they are more likely to pick up other coronaviruses, and so have some underlying immunity.
While adults pick up a cold around two to four times a year, school age children catch an average of 12 colds annually, and many of these infections share similarities with Covid.
A recent Public Health England (PHE) report found that many people in Britain are already immune to coronavirus even though they have never been infected, probably because of this cross-reactivity.
And among those who had never had coronavirus, the under-30s were more likely to have high levels of coronavirus fighting T-cells compared to the over-60s, which could help explain why the risk lessens with decreasing age.
The immune systems of young people may also be better at reacting to new viruses. By about the age of 65, most adults no longer have a working thymus so their T-cells look at whether they have seen something before, whereas children are good at responding to unknown pathogens.
Older people also suffer from immune cell ‘senescence’ where their immune cells start to shut down but are not cleared away and replaced with a working version, making them more vulnerable to disease.
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Dr Julian Tang, Honorary Associate Professor/Clinical Virologist, Respiratory Sciences, at the University of Leicester says the recent research strongly suggests "that primary school children are less symptomatic and shed less Covid-19 virus compared to secondary school children (who are more like adults from the virus viewpoint), but this risk is not zero.
“So unfortunately, there is still a risk of younger children spreading the virus to granny.
“It would be more prudent and cautious not to allow any close contact between young children with the unvaccinated elderly this Christmas because even if the transmission risk is small, you don’t know if you will be the unlucky one – and as we know, when it comes to more vulnerable people, the harm can be enormous.’
“I would advise children to wave at granny from a distance this year and hug next year – she will understand.”