In September, the majority of children in England returned to school, but there has been increased discussion about the threat of Covid-19 to young people, and how the virus affects them compared to adults.
On 28 August, a BMJ study was published which found the need for children to have hospital treatment for Covid-19 was "tiny" and critical care "even tinier".
It said parents should be "reassured" Covid-19 has not caused the deaths of any otherwise healthy schoolchildren in the UK. However, black children, obese children and very young babies have a slightly higher risk.
Deputy chief medical officer, Jennie Harries said on Monday that the risk of seasonal flu or a car accident to students was "probably higher" than the current risk presented by coronavirus.
And prime minister Boris Johnson said the risk of contracting Covid-19 at school was "very small". He said "it is far more damaging for a child's development and their health...to be away from school any longer."
Early on in the coronavirus pandemic much of the concern about threat to life was around older people, particularly those in the over 75 group or with underlying health conditions.
On 24 April, Great Ormond Street Hospital said: “The evidence to date suggests that although children do develop Covid-19, very few children develop severe symptoms, even if they have an underlying health condition."
But what about transmitting the virus to adults?
In Switzerland, authorities said on 29 April it was safe for children under the age of 10 to hug their grandparents because young children “do not transmit” the virus. But German virologist Christian Drosten conducted a study in May, which found children “may be just as infectious as adults”.
As understanding has developed - what is the current understanding about how coronavirus impacts children? And is it different between primary and secondary age children?
So can children pass coronavirus onto adults?
On 23 August, Professor Chris Witty cited evidence of children "much less commonly" needing hospital treatment or becoming severely ill with coronavirus than adults.
According to the Office for National Statistics data on ages there were 10 recorded deaths as "due to Covid-19" among those age 19 or under in England and Wales between March and June 2020.
A Public Health England study found of the one million children who went into pre-school and primary school before the summer holiday, in June, 70 children and 128 members of staff were infected in outbreaks.
It said of the 30 outbreaks detected in that time, most had likely been caused by staff members infecting other staff members, with only two instances thought to involve students infecting other students.
In April, a report published on the Don’t Forget the Bubbles blog, in partnership with the Royal College of Paediatrics and Child Health, outlined findings by the World Health Organisation (WHO) which “could not recall episodes during contact tracing where transmission occurred from a child to an adult”.
But it did warn there was no certainty. ”The role of children in transmission is unclear, but it seems likely they do not play a significant role,” it stated.
Speaking to The Independent, Dr Alasdair Munro, who compiled the research said that studies have shown that children “have a lower attack rate than adults”, that children “are less likely to acquire it from a household contact than adults are” and that children “are less often the people bringing it into the household than adults”.
A UCL study, published in May, found children "appear half as likely to catch Covid-19 as adults" but warned that "evidence remains weak on how likely they are to transmit the virus". It was the largest study of its kind, including a systematic review of more than 6,000 international studies into Covid-19 spread.
"Susceptibility is a key part of the chain of infection, and this supports the view that children are likely to play a smaller role in transmitting the virus and proliferating the pandemic, although considerable uncertainty remains," it said.
A study published in The Lancet in June, concluded: "Covid-19 is generally a mild disease in children, including infants. However a small proportion develop severe disease requiring ICU admission and prolonged ventilation, although fatal outcome is overall rare."
Should we still express caution about children's ability to pass on the virus?
Much of the research on children has focused on young primary-age children, not on those of a secondary school age.
In August the World Health Organisation warned that young people could be driving spikes in coronavirus across Europe.
There was also concern closer to home with Preston Council warned young people "Don't kill granny" after it discovered that half of new cases were occurring in people aged under 30.
A study by French epidemiologist Arnaud Fontanet at a school in France found that although younger age groups do not "transmit to the same extent", "teenagers are just as contagious as adults".
Labour shadow education secretary Kate Green has said that the government policy of not making children wear face masks in secondary school, is something that should be kept under review.
She says this is because we don't yet know how best to manage safely returning to school from next week: "I think it's really right that it's kept under very close watch as to where they might be appropriate in school [and] whether they might be appropriate in school."
Dr Simon Clarke, associate professor of cellular microbiology at the University of Reading, says it is important to “err on the side of caution” when discussing whether the coronavirus can be transmitted to adults by children.
“Given that not many pieces of work have been done on it, it’s very difficult to judge,” Dr Clarke told The Independent in April. “There’s not a mountain of evidence on both sides. The fact is we know very little about this, precious little.”