In this file photo dated May 27, 2020, a daycare worker in Tacoma, Washington, wears a mask while cleaning a tricycle after being used by a class. This task is repeated several times a day.
Ted S. Warren | AP
Twelve children, likely caught Covid-19 in three Utah daycare centers, spread the virus elsewhere and infected some parents and siblings. This is according to a new study published Friday by the Centers for Disease Control and Prevention.
The study's authors note that research had previously shown that children ages 10 and up can spread the virus in schools. The new study is evidence that even younger children, including an 8-month-old baby, can still spread the virus even though they are not seriously ill with Covid-19, the researchers said.
The study looked at outbreaks that occurred in three daycare centers in Salt Lake City between April and July. Using the contact tracing data collected at the time of the outbreak, the researchers used the data to "post-build chains of transmission" to determine exactly how the virus spread. A total of 83 children attended the three daycare centers included in the study, the researchers said.
Among the three outbreaks, the researchers said 12 children in daycare were infected with Covid-19, although three of them never developed symptoms and nine developed only mild symptoms. The study says these 12 children came into contact with 46 people unrelated to childcare facilities and appeared to have infected 12 or more than a quarter of them. Those infected by the children include six mothers, one of whom has been hospitalized, three siblings and three others, the study says.
"Transmission has been seen in two out of three children with confirmed, asymptomatic COVID-19," the researchers wrote, adding further evidence that those who do not have symptoms of Covid-19 can still spread the virus. "COVID-19 is less severe in children than adults, but children can still play a role in transmission."
The role that children, especially asymptomatic children, play in spreading the virus has become a controversial issue as the debate continues on whether and how to reopen schools for personal learning. While the researchers focused specifically on childcare facilities and not necessarily schools, they recommended testing as a useful tool for mitigation and research.
"Two out of three asymptomatic children have likely transmitted SARS-CoV-2 to their parents and possibly their teachers," they wrote. "Having SARS-CoV-2 tests available, timely results, and patient contacts tested in childcare facilities regardless of symptoms can help prevent transmission and better understand the role of children in transmission."
The researchers noted some limitations to their study. Between April 1 and July 10, Salt Lake County identified 17 daycare centers with at least two confirmed Covid-19 cases within a 14-day period. However, the study only includes data on three of these centers.
The researchers added that the guidelines for the contact tracing methodology changed during the pandemic and could have resulted in inconsistent data collection systems. They also said the initial testing criteria were more restrictive and could have resulted in an outnumber of infections.
Finally, the researchers found that at one of the centers they could not find the source of the outbreak, so it is possible that cases at the center were submitted from a different source. In the other two facilities, the researchers said they traced the source of the infection back to employees who became infected with Covid-19 through a family member.
"Testing contacts of laboratory-confirmed COVID-19 cases in childcare facilities, including children who may not be symptomatic, could improve control of transmission from childcare participants to family members," the researchers concluded.