Are molecular tests less effective with the Covid variant? The WHO alarm
All the problems that the tests with the Covid variant could have according to the WHO
While Moderna and Pfizer are testing vaccines to verify their effectiveness against the UK-certified variant of the coronavirus (in circulation since November, actually), WHO launches on the diagnosis front.
Some types of tests, in fact, are less effective in detecting the infection.
Let's go step by step.
VARIANT SARS-COV-2, WHO ALARM ON TESTS
Let's start with the diagnosis. Some tests, as found by the World Health Organization, may be less effective in detecting the English variant of Covid, or rather one of the 14 mutations that characterize the variant. In particular, explains Adnkronos , "concern is expressed about the reported loss of performance for some PCR tests", a technology used for molecular swabs.
THE LESS EFFECTIVE TESTS
Some studies have found that a variant mutation, ie "the deletion in position 69/70, affects the performance of those targeting the S (Spike) gene".
LIMITED IMPACT?
It must be said, however, that "the majority of PCR tests worldwide use multiple targets and therefore the impact of the variant on diagnostics is not expected to be significant".
The impact on diagnostic tests, therefore, should be limited.
WHAT IS RECOMMENDED TO LABORATORIES
Why then raise the alarm? Because WHO intends to advise “laboratories using commercial PCR kits for which the targeted viral genes are not clearly identified in the instructions to contact the manufacturer for further information. Labs using internal PCR tests that target the virus's S gene should also be aware of this potential problem. In order to limit the impact on "infection" detection capabilities in countries, an approach that uses several assays in parallel or multiple assays, targeting different viral genes, is also recommended to allow detection of potential variants ".
THE COUNCILS OF THE ECDC
The European Center for Disease Control , Ecdc, had also said that there could be problems on the diagnosis side, which had asked European laboratories to double-check and update the nucleotides used in the various diagnostic methods of Sars-Cov-2, such as molecular swabs. and rapid antigen tests.
The ECDC, just like the WHO, argued that testing cannot rely solely on the detection of variants on the S-gene and recommends confirmation using sequencing. For this reason, the ability to characterize the virus genetically and antigenically, or to share the isolated sequences with reference laboratories, must be increased.
AND VACCINES?
In addition to the diagnosis front, could there also be problems on the treatment side? Pfizer and Moderna have already started tests to test the vaccine's effectiveness on the variant.
There should be no major problems, however.
“Based on data to date, we expect Moderna vaccine-induced immunity to protect against recently tracked variants in the UK; we will carry out further tests in the coming weeks to confirm this expectation, ” say da Moderna.
"From a scientific point of view, however, it is highly probable that our vaccine can also defend against this variant," said Biontech founder Ugur Sahin.
This is a machine translation from Italian language of a post published on Start Magazine at the URL https://www.startmag.it/sanita/i-test-molecolari-sono-meno-efficaci-con-la-variante-inglese-del-covid/ on Wed, 23 Dec 2020 14:56:11 +0000.