According to the results of a preliminary study, the reliability of the tests – nasopharyngeal or salivary – would vary according to the type of variant
In France, PCR and nasopharyngeal antigen tests are now widely preferred to detect Covid-19. But, are they the most effective in spotting the Omicron variant? According to the “JDD”, more and more experts believe, in fact, that saliva tests “would allow earlier detection of this variant and would limit the risk of false negatives”.
The “Journal du Dimanche” cites in particular an article from the “New York Times” which, based on a preliminary study published in the medical journal “MedRxiv” – and whose results have yet to be confirmed -, explains that with the variant Omicron, the saliva test is 100% reliable compared to 86% with a nasal swab. For the Delta variant, on the other hand, the figures are reversed: it is the nasopharyngeal test which is 100% reliable against 71% for the saliva test. The reliability of the tests would therefore depend on the type of variant.
In France, where saliva tests have been offered since February 2021, the Ministry of Health is, according to “the JDD”, studying the question and “generating data” in order to compare the two screening methods.