"Our study was not created to prove that younger children spread Covid-19 as much as adults, but it is a possibility", Heald-Sargent added.
They looked at 145 patients who developed to moderate illness within one week of experiencing symptoms. Yet, there was no data as to what extent young children are able to spread the virus. The investigators then recorded PCR amplification cycle CT values, with "lower values indicating higher amounts of viral nucleic acid".
They compared the viral load in three age groups - children younger than 5 years, children 5-17 years and adults 18-65 years.
Image: A microscopic image shows SARS-CoV-2 from a patient in the US.
'We found that children under five with COVID-19 have a higher viral load than older children and adults, which may suggest greater transmission, as we see with respiratory syncytial virus, also known as RSV, ' said lead author Dr Taylor Heald-Sargent, a pediatric infectious diseases specialist at Lurie Children's.
In a commentary accompanying the publication of the new studies, deputy editor of JAMA Cardiology Clyde Yancy and section editor Gregg Fonarow call for urgent ongoing research to better understand the cardiovascular complications associated with COVID-19, as preparations may be necessary for what could be another dimension to this pandemic crisis.
Regarding the public health implications of the findings, Heald-Sargent said this population of younger children will be important to immunize as vaccines against SARS-CoV-2 become available.
The authors state that this does not necessarily mean that children younger than five are more capable of passing the virus on to others, but suggest that the findings could influence the debate over the reopening of schools.
Most notably, only 33 percent of the cohort studied required hospitalization during the course of their COVID-19 infection.
"There is evidence now that the virus can directly attack heart muscle cells, and there's also evidence that the cytokine storm that the virus triggers in the body not only damages the lungs, but can damage the heart", says Swartzberg, who did not work on either of these new studies.
The study is significant in "pointing to the scale and nature of the problems that zoonotic transmission presents to humans", reported BBC citing Mark Pagel, professor of the University of Reading, who was not involved in the study.
"I think it's good news, because once the infection clears, olfactory neurons don't appear to need to be replaced or rebuilt from scratch", Datta said.
According to the researchers, this study suggests that the behavioural habits of young children, as well as the close proximity in schools and daycare centres, may raise concern about the virus spreading.