Large COVID Outbreak at Nursery Shows Toddlers Can Spread Disease, CDC Report Says

A nursery in Poland has been linked to an outbreak of the coronavirus involving over two dozen people, raising questions about how easily the virus spreads among young children.

Twenty-nine people caught the virus at the nursery, which was cited in a research letter published in the journal Emerging Infectious Diseases, published by the CDC. Cases included eight children who went to the nursery, and 12 family members who did have contact with the facility: three siblings, eight parents, and one grandparent. The children at the nursery were aged between one and two years old. Two of the children in their respective families were aged eight and five.

The authors affiliated with Poland's Medical University of Warsaw noted the cluster represented a "surprisingly high spread" of the coronavirus in the nursery, and called into question the "presumed negligible role of children" driving the pandemic. "Children 1–2 years of age might be effective SARS-CoV-2 spreaders," they wrote.

The nursery reopened on May 18 after a nationwide lockdown across the eastern European country, but was closed on May 31 after a worker said a family member had caught the coronavirus. The worker was diagnosed with coronavirus on June 4. A further 104 staff, children and family members were later tested.

It is unlikely that the individuals caught the coronavirus outside of the nursery, as there were low levels of the virus in the Polish population at the time, according to the authors of the study. In June, 124,194 cases tests were carried out and 1,374 came back positive, the team said. As shown in the graph below by Statista, Poland is not among the countries with the most known coronavirus cases. According to Johns Hopkins University, of 37.5 million coronavirus cases worldwide, Poland makes up over 130,000.

The authors wrote: "Children seemed to be effective mediators of infection between adults." They noted in the study that nursery workers and family members who were infected had little contact, and the family members of the different children "did not mix."

The findings may be "particularly important," they said, following the publication of a study in the journal JAMA Pediatrics in the summer that suggested children may be "important drivers" in the spread of the coronavirus.

The children may have caught the virus because they were in close contact with one another, less able to follow guidelines to prevent the spread of disease, and the nursery was a confined space, according to the study. In addition, close contact between family members and children may explain how the virus was passed on in households.

In the two-week period when the nursery was open, 25 children on average attended it for eight hours each day. The children went to nursery in three groups, with two caregivers assigned to each. The staff wore masks when interacting with the children, and the kids in the groups did not mix. When dropping children off at the nursery, parents did not enter the building, and made contact with workers for less than 15 minutes.

Past reports on coronavirus outbreaks in childcare settings suggest it is unlikely that children can infect each other and adults. But the team said those may have been biased as the data was collected during lockdown when children were only in contact with family members, and largely included school-age children.

Acknowledging the limitations of the study, the researchers said it was not possible to prove the worker started the outbreak, as a parent tested positive two weeks prior to their diagnosis and a child could have been the first case. And as most of the people involved in the outbreak did not have symptoms it was not possible to confirm whether the children passed the virus on to their parents or workers.

Ian Jones, professor of virology at the U.K.'s University of Reading, who did not work on the study, told Newsweek there have been a few studies on the coronavirus spreading among children. "The general view has been that it is not rampant, maybe as most cases are asymptomatic so there is not a lot of coughing."

"This study, of a nursery in Poland which re-opened after lockdown, finds a much higher rate but given the previous studies it is hard to know which situation is more likely to be typical. Certainly, since schools have re-opened in the U.K. there have not been major outbreaks, in contrast say, to universities.

"Perhaps the best view would be to recognize that outbreaks can occur in nurseries but that they do not seem to be notable sources of onward transmission. Caution but not alarm would seem the appropriate position to adopt."

Co-author Joanna Mańdziuk of the Department of Pediatrics at Poland's Medical University of Warsaw told Newsweek via email the take-home message for readers was that "contact with young children can result in catching the virus. Perhaps contact with young children can be particularly risky compared to older children because of specific, intimate contact with them (helping with all the daily higiene routine, hugging, etc)."

Mańdziuk said conclusions drawn from the study "must be interpreted with caution" as it looked at one cluster in a single nursery. More data needs to be collected on the spread of the coronavirus among small children and their carers to draw conclusions about their role in driving COVID-19 pandemics, she said.

This article has been updated with comment from Joanna Mańdziuk.