Thread by @DrEricDing

📍Variant “bypasses” PCR tests—French govt is warning of a new #SARSCoV2 variant that escapes detection by standard PCR tests. Because is it harder to detect, WHO has placed it in category of “variant under investigation” due to its bypassing PCR tests. 🧵
politico.eu/article/new-fr…

2) Good thing is that so far, the “initial analyses of this new variant doesn’t suggest either increased severity or increased transmissibility”.

3) However, the French authorities are not fooling around — they have released an URGENT bulletin warning about this new variant that was discovered in Brittany (of France).

https://twitter.com/Le___Doc/status/1371571615713071108

4) Here is a translation of the French govt warning: “A nosocomial cluster of SARS-CoV2 infections has been monitored for several weeks by ARS Bretagne with cases also detected in community settings.

solidarites-sante.gouv.fr/IMG/pdf/dgs-ur…

5) “Following the detection of several cases linked to this cluster with a repeated discordance between the clinical signs suggestive of COVID-19 & negative results of RT-PCR carried out on a nasopharyngeal sample, epidemiological and virological investigations were carried out.

6) “The molecular analysis carried out by the CNR de Pasteur reveals a new variant (derived from the 20C clade) carrying nine mutations in the region encoding the S protein but also in other viral regions.

7) “An evaluation is underway in order to assess the possible impact of these genetic modifications on a lack of recognition by virological tests leading to an under-diagnosis and likely to interfere with the screening and contact-tracing strategy currently in force.

8) “Additional investigations are also underway to assess the impact of these mutations on the transmissibility, severity and possible risk of immune escape of this new variant.

9) “ At this stage, and in the absence of data to date concerning a possible increased transmissibility of this virus compared to the strains of 2020 and a possible greater frequency of severe forms—classifies this strain as "variant under investigation ”

10) In view of the possible failure of the biological diagnosis on nasopharyngeal samples, specific action to be taken must be implemented.

11) “What to do with possible, probable and confirmed cases:
All cases meeting the definition of possible/probable must be subject to strict isolation for a period of 10 days from date of onset of signs for symptomatic patients or from the date collection for asymptomatic cases.

12) The letter from the French health minister goes on with other precautions. But it is pretty worrisome that they’ve been tracking this mystery for a few weeks and finally realized it is COVID.

Honestly, if this variant happened elsewhere, I doubt Florida would even notice.

13) Is France the only country to notice such a new variant that evades PCR tests? No, Finland 🇫🇮 also just discovered a new variant that escapes classic PCR lab tests too.

Worrisome trend. dailysabah.com/life/health/ne…

14) This is not a new phenomenon. Technically our PCR shortcut test for the #B117 relies partially on the same phenomenon— where the 69-70 deletion mutation in the spike protein gene causes partial signal drop out in the TF taqpath PCR test. This is how we track B117 mostly.

15) THINK OF IT THIS WAY—its remarkable that the virus may have actually somehow selectively evolved a mutation that allows it to surreptitiously transmit farther by evolving a mutation that goes less detected! Just when we think we figured it out, it mutates a new hat 🎩 trick.

16) But wanna know what works against such a variant? It’s easy...

Masks. Ventilation. Vaccination.

They still work—even without testing. This is why mitigation measures have to stay in place for a while even after vaccination.

17) Dr Bari is correct — an infected person that is never isolated by a positive #COVID19 test will continue to keep spreading — thereby reinforcing that virus’s mutations to evade tests. It’s the ultimate cat and mouse game during this pandemic.

https://twitter.com/njbbari3/status/1371866025298333696

18) Someone asked if the new variant has an official name yet. Not sure, but it’s from the 20C lineage. I guess it’s the France-Bretagne (Brittany) variant for now.

Note—not that Britney.

19) This PCR test evading French variant is all the more reason we need more rapid antigen tests, like the winners of the @xprize @OpenCoViDScreen initiative to help get more rapid tests developed. Thx @jhuber.