Coronavirus: Testing, tracking can keep students’ COVID-19 risk low, studies say
Schools and nurseries don’t pose a high risk of spreading coronavirus when proper testing and tracking measures are used, according to a study that found a small percentage of people contracted the disease from infected peers and teachers.
Only 1.2 percent of people caught the virus after they were in contact with 27 children or teachers who were infectious, according to a study of schools and nurseries in New South Wales, Australia, where track, trace and isolation measures were used.
Further analysis of seven sites found the disease was less likely to spread from child to child than from staff to staff, researchers said Monday in The Lancet Child & Adolescent Health journal.
Concerns over resurgent infections have grown as countries struggle to re-open schools and childcare centers full-time. Federal data show that children account for more of total infections than previously thought in some US states, spurring those such as California to reverse course and continue with online classes.
While children account for a very small proportion of COVID-19 deaths, researchers still aren’t sure of their overall role in the pandemic.
“We urgently need large-scale research programs to carefully monitor the impact of schools reopening,” said John Edmunds, an infectious disease professor at the London School of Hygiene & Tropical Medicine, in a commentary in the journal. “Many questions remain, including whether there are age-related differences in susceptibility and the likelihood of transmission between children and adolescents.”
The Australian study looked at all the close contacts – those with face-to-face interaction for a minimum of 15 minutes or 40 minutes in an indoor space – of confirmed cases in 25 schools and nurseries. Of 1448 contacts, 18 developed COVID-19 from transmissions in three schools and one nursery.
One event’s impact
A single event in which one adult passed the disease to six more adults and seven children accounted for most of the cases. Without this incident, the transmission rate would have fallen by a third to 0.4 percent. In the analysis of schools and nurseries that were given more tests, children were slightly less likely to infect staff than vice versa.
The investigators cautioned that the findings must be seen in context with how Australia has managed the outbreak, with two lockdowns in a number of states and fewer infections and deaths than a number of smaller countries. Of 1.8 million children in New South Wales, only 98 children were infected, or about 3.2 percent of total COVID-19 diagnoses, according to the study.
A second study published Monday in the same journal modeled six different school reopening scenarios, including full- and part-time rota systems, to see the potential impact on transmission.
The London researchers predicted that, taken with other lockdown-easing measures, a second wave of the virus could be avoided if 59 percent to 87 percent of symptomatic people are tested at some point during their infections and appropriately followed up on.
If diagnoses and contact tracing are not sufficient and schools open full-time in September, it will likely spur a second spike in infections that would peak in December. A part-time school rota might lead to another peak in February, according to the study.