A study published today in Lancet Child and Adolescent Health by researchers at King’s who looked at data from the ZOE COVID Study found that COVID-19 is a short, mild illness for most children. What’s more, children are unlikely to suffer from long duration COVID symptoms. Here’s what we know so far about COVID in kids.

• How did we investigate COVID symptoms in children?
• What symptoms do children with COVID experience?
• How long does COVID last in children?
• How does COVID-19 compare to other illnesses in children?
  

While we appear to be past the worst in terms of deaths and hospitalisations from COVID-19, many people are worried about the longer term impacts of COVID on health.

Our previous research showed that up to 1 in 7 adults experienced COVID-19 symptoms for more than four weeks, and 1 in 20 suffered from symptoms for more than eight weeks. As a result, long COVID or post-COVID syndrome has now been officially recognised and is defined as having symptoms that linger for 12 weeks or more.

With COVID-19 cases booming in unvaccinated children and younger people thanks to loosening lockdown restrictions, there has been some concern among parents about whether children can suffer long term effects from the virus too.

To find out more about how COVID-19 affects children, we collaborated with researchers from King's College London to analyse symptom data from children recorded in the ZOE COVID Study app. Here’s what we found. 

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How did we investigate COVID symptoms in children?

Children under 16 can’t log symptoms in the ZOE COVID Study app themselves, but more than 250,000 parents and carers have been logging symptoms on behalf of their children over the past year. 

To find out more about COVID-19 in children, we analysed the symptoms reported for children between September 2020 and February 2021 when COVID cases were widespread, and there was easy access to testing to confirm positive cases.

We analysed data from more than 1,700 children who had a positive PCR swab test and reported COVID-19 symptoms around the date of their test result. We looked at the type, number and duration of symptoms in children, including relapses and reoccurring symptoms, which are common in adult long COVID sufferers. 

We also compared the symptoms of children who had COVID-19 with children who experienced similar symptoms but tested negative so that we could compare the effects of COVID with other winter respiratory viruses like coughs, colds and flu. 

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What symptoms do children with COVID experience?

Reassuringly, children only reported three symptoms of COVID in the first week on average, emphasising that COVID is a mild illness for most children. 

The most common symptoms were headache and fatigue, reported for 62% and 55% of children, respectively.

“There's been some press commentary about kids having dizziness, confusion, disorientation and drowsiness which might affect their schooling, but we found these symptoms were uncommon in children,” says Professor Emma Duncan from King’s College London, who led the study. 

Interestingly, the classic three symptoms required for an NHS PCR swab test were less common in children, with 40% reporting anosmia, 38% developing a fever, and 26% suffering from a cough. 

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How long does COVID last in children?

Using the data from the ZOE COVID Study app, we calculated that the average duration of COVID symptoms in children is six days.

Our data showed that fewer than 1 in 20 children with symptomatic COVID-19 had symptoms lasting longer than four weeks, with slightly more children of secondary school age experiencing long duration symptoms compared with children of primary school age. 

Almost all children were fully recovered within eight weeks, with only 1 in 50 children still unwell after eight weeks, compared with 1 in 20 adults. 

“Our research confirms that a small number do have a long illness duration with COVID-19, though these children too usually recover with time. We hope our results will be useful for doctors, parents, and schools caring for these children - and of course, affected children themselves,” says Emma. 

Importantly, our data only shows the proportion of children who experienced long duration symptoms out of all symptomatic cases. “We know from other studies that around half to two-thirds of children who catch coronavirus don’t show any symptoms at all,” says Emma. 

As a result, the true proportion of children infected with COVID who experience long-lasting symptoms is likely to be much lower than our data suggests, making extended illness in children rare. 

Similar to adults, children who had more symptoms in the first week were more at risk of having extended symptoms than children who had fewer symptoms in the first week. However, by day 28, children who still had symptoms only reported an average of two symptoms, with fatigue, headache and anosmia the most common.

The full results of our analysis have been published in The Lancet Child and Adolescent Health. 

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How does COVID-19 compare to other illnesses in children?‍

When we compared the symptoms of children who tested positive for COVID with children with other respiratory viruses, we found that they reported similar symptoms, with a sore throat, headache, fever and fatigue among the most common. 

We saw that illnesses caused by other respiratory viruses were shorter in duration than those caused by COVID-19, with an average duration of 3 days. Furthermore, fewer children had long-lasting symptoms compared with children with COVID. However, those who were still unwell at day 28 had more symptoms than children still sick with COVID, with an average of 6 symptoms ongoing. 

“It’s also important that we remember that there are other infectious diseases that can leave children unwell for many weeks, and these children shouldn’t be overlooked,” says Emma. 

As the pandemic marches on, we’re continuing our investigations into the effects of COVID-19 on children and adults. You can contribute to our research by downloading the ZOE COVID Study app and completing daily health reports for yourself and your children.

Stay safe and keep logging.