Parents have been advised to “moderate” their social contacts in the coming weeks to ensure their children successfully return to school.
An increase in the incidence of Covid-19 among children after school reopening depends in part on the effectiveness of school mitigation measures, according to National Public Health Emergency Team (Nphet) member Prof Philip Nolan.
Another factor is whether adults increase their contacts or return to the workplace, he says.
“The successful return to school depends on the hard work of all to put those mitigation measures in place, the strict exclusion of the symptomatic, parents moderating their social contacts especially in the first few weeks, and careful monitoring,” he said on Monday.
International evidence shows the risk of children transmitting the virus is probably lower overall, and is lower in schools with effective mitigation measures than in communities and households, Prof Nolan said.
This was also the experience of Irish public health officials, he added. “There is considerable evidence that, with effective mitigation measures in place, schools are not major sites of transmission, and this is affirmed by the experience of public health doctors who supported the safe opening of schools in spring 2021.”
But he acknowledged schools face a new challenge, as there is no experience of opening schools amid the Delta variant and with such high levels of circulating virus among young people as at present.
Modes of transmission
While the variant is more transmissible, this does not mean the modes of transmission are different from those of previous strains of the disease, according to Prof Nolan, writing on social media.
“Where in-school transmission has been observed, it tends to be amongst friendship groups and in high-contact situations, suggesting that direct contact, droplets and short-range aerosol are the dominant modes of transmission in this setting.
“Delta does not transmit differently, it transmits more efficiently, and it is reasonable to assume that mitigation measures that were effective against [the] Alpha [variant] will also be effective against Delta, though they need to be strictly observed, and the situation monitored.”
While there are international reports of increasing Covid-19 incidence among children in Delta outbreaks, this does not imply they are more susceptible to this variant “or that schools are important sites of transmission”, he said.
“While the increased transmissibility of Delta is a concern, we should remember that in March 2021 we were equally concerned about the opening of schools with a new, more transmissible variant, the Alpha variant.”
Prof Nolan said there was considerable international evidence that younger children are less susceptible to the virus than adults. To date, he added, school openings and closures have had minimal effect on incidence in the population as a whole.
“While there have been transient increases in incidence after each reopening, these have not been sustained,” he stated.
Mitigation measures in place in schools in the last academic year included social distancing, handwashing, reductions in mixing between different groups of pupils and, at second level, the use of masks. Since then, carbon dioxide monitors have also been installed in all schools to check on air quality.