Children and babies as young as eight months old have been shown to transmit Covid-19 to adults after outbreaks at three childcare centres, according to the Centres for Disease Control and Prevention.
The findings come as schools and daycare facilities across the country increasingly reopen to in-person contact, with the CDC continuing its research for guidance on controlling the spread of coronavirus.
The new report, released late on Friday, studied coronavirus outbreaks at three childcare facilities, attended by 83 kids, in Salt Lake City, Utah from 1 April to 10 July.
Twelve children under the age of 10, who likely contracted the virus at daycare, were found to have infected some of their parents or siblings after returning home, even if they showed no signs or symptoms.
Researchers said that previous studies have shown children aged over 10 years could spread the virus in schools, but this new study is clearer evidence it can be spread by younger children who don't get severely sick.
While those who did show symptoms were mild, one case of an eight-month-old who spread it to both parents required one of them to be hospitalised.
Of the 12 documented cases in children, Covid-19 was spread to at least another 12 people of the 46 they came into contact with who were not related to the childcare centre, such as parents, siblings, and other family members.
"Covid-19 is less severe in children than it is in adults, but children can still play a role in transmission," the CDC report said.
"The infected children exposed at these three facilities had mild to no symptoms. Two of three asymptomatic children likely transmitted Sars-CoV-2 to their parents and possibly to their teachers."
The report recommended increasing testing, contact tracing, and increased hand hygiene to reduce transmission.
