Sir, – In your editorial, you correctly express concern about the recent mixed public health messaging around the role of rapid antigen tests for the detection of Covid-19 ("The Irish Times view on antigen testing: A study in mixed messaging", May 11th).
There should be no confusion: these tests cannot reliably exclude Covid-19 infection in those without symptoms; some studies have shown detection rates of around 50 per cent , particularly for self-administered tests. This is akin to tossing a coin.
While a positive result may act as a “red light” and thus provide a warning, a negative self-test result in an asymptomatic individual should not be used as a “green light” or provide reassurance to allow entry to social or work settings.
Public health messaging should be adjusted accordingly. – Yours, etc,
Prof EDMOND SMYTH,
Consultant Microbiologist,
Beaumont Hospital,
Dublin 9.