Sir, – Seán L'Estrange (Letters, September 22nd) attempts to reassure the public that school attendance is unlikely to be a driver of increased Covid-19 transmission on the basis that infection rates for children are in line with the rest of the population.
Unfortunately coarse infection rates like these provide little insight. Any child who becomes infectious will return home to infect perhaps one or two and in many cases three or more people in their household who are older.
If school attendance is a contributor to transmission, we are thus unlikely to see a higher rates of positive tests for children compared to adults, only a higher rate overall.
It is noticeable that the number of positive tests in the weeks beginning August 24th and 31st were 812 and 818 respectively, while the following two weekly figures were 1,196 and 1,808.
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Allowing a one-week or two-week lag time for incubation and testing, the period when schools reopened was the period when infections began to rise sharply. This may be coincidental; correlation is not causation. HSE officials have been open that they do not endeavour to identify the source of all infections, so we may never know for certain.
If Mr L’Estrange and his colleagues at UCD were able to provide figures about the rate of infection over this period of adults in households with children in education (primary, secondary and tertiary) compared to adults of similar age in households without children, that might be more informative. – Yours, etc,
JOHN THOMPSON,
Phibsboro,
Dublin 7.