Children are far less likely to suffer from Covid-19, a new study has confirmed, with just four per cent of children admitted to hospital testing positive for the virus.
Why children are less affected by the coronavirus than adults remains unknown, but it is believed to be down to the way their immune system reacts after infection.
The research looked at the test results of more than 135,000 children admitted to seven US hospitals before September 8.
It revealed only 5,374 (4.0 per cent) of patients tested positive and, of this small percentage, only 359 (6.7 per cent) were hospitalised, with 99 needing intensive care.
Eight of the infected patients (0.15 per cent) later died. Six of the deaths were patients with ‘complex preexisting comorbidities’, the scientists say.
The research looked at the test results of more than 135,000 children admitted to seven US hospitals up until September 8. It revealed only 5,374 (4.0 per cent) of patients tested positive and, of this tiny percentage, eight died (stock image)
The study comes from doctors at the Children’s Hospital of Philadelphia who looked at electronic medical records from seven children’s hospitals in the US.
The average age of the patients was almost nine years old, but they ranged from less than one year old to legal adults who were older than 18.
A history of certain factors increased the likelihood of a positive test, the data shows.
For example, people with a history of heart issues were 18 per cent more likely to test positive and a history of mental health was linked to a 20 per cent increase in risk.
However, a history of asthma or other respiratory conditions was not associated with increased positive test results.
White children made up 60 per cent of all admissions but accounted for just 40 per cent of the positive cases.
Hispanic, black and Asian children made up a disproportionately high number of those infected.
‘Although black, Hispanic, and Asian patients were significantly less likely to undergo testing, these groups had a markedly increased chance of a positive test result,’ the researchers write in their study, published in the journal JAMA Paediatrics.
Black children are 2.66 times more likely than average to register a positive test, with Hispanics and Asians 3.75 and 2.04 times more likely to be infected, respectively.
Patients with a history of heart issues were 18 per cent more likely to test positive and a history of mental health was linked to a 20 per cent increase in risk. However, a history of asthma or other respiratory conditions were not associated with increased positive test results (stock)
Patients with a progressive long-term medical condition were nearly six times as likely to develop severe disease following infection.
‘While the overall risk is low in this group of children, we see significant disparities in those who are testing positive and developing severe disease, which follows what we see in adults,’ said study author Dr Hanieh Razzaghi.
A recent study found children can test negative for Covid-19 despite living with infected parents, having mild symptoms and creating antibodies.
In an Australian family of five, two parents became infected with the coronavirus and passed it on to their three children, but none of them ever tested positive.
While the adults developed classical symptoms such as a cough, fever and headache, two of the children only had very mild symptoms and the youngest was completely asymptomatic despite sleeping in the same bed as the parents.
However, all five had the same immune response, with antibodies specific for SARS-CoV-2, which causes Covid-19, found in blood and saliva samples of everyone.
But despite this, none of the children ever tested positive for Covid-19 in PCR throat and nose swabs, seen as the gold-standard for detecting infection.
Researchers say the case study from the Murdoch Children’s Research Institute (MCRI) in Melbourne indicates children can mount a strong response against the virus once it gets inside their body which prevents it from replicating, limiting its potency.
Another piece of research, from UCL and the Francis Crick Institute, found that 44 per cent of under-16s have antibodies designed to fight off the common cold which also neutralise the SARS-CoV-2 coronavirus which causes Covid-19.
Scientists are currently unable to explain why the presence of these cross-virus antibodies differs in adults and children.