Guillaume Rozier, founder of this site for monitoring epidemic numbers, believes that disruptions in screening methods can no longer allow reliable data on the alternative.
Does France still have the means to follow the rapid development of the Omicron variant on its territory? Guillaume Rozier, the data specialist at the origin of the CovidTracker website, which makes it possible to track epidemic numbers, and ViteMaDose, which makes it possible to book a vaccination window, have been moved on Twitter so that CovidTracker is no longer able to document the circulation of the Omicron variant. The reason: a change in the sample testing methodology for coronavirus testing.
CovidTracker uses public data from data.gouv.fr to feed its perceptions regarding the circulation of the virus. However, while the government website has so far reported data from examining part of the positive samples taken in France, this data has been underreported, to the point where it has become difficult to use.
A problem already raised by Florence Debar, a researcher at CNRS, before Christmas.
Until November, screening tests were intended to detect specific mutations in the virus: E484K, E484Q and L452R, with their code A, B and C. This variant circulated among the French. “By pure chance or luck, Omicron does not have this C mutation, unlike Delta. Thus, following the ratio of states without C allowed us to get a good approximation of the Omicron states.‘ explains Guillaume Rosier.
However, to improve this monitoring, Santé Publique France explained that since December 20, 2021, the screening includes monitoring for mutations of the Omicron variant, “Such as deleting 69/70 and replacing K417N, S371L-S373P, and Q493RA new code, D, must therefore be added to the previous three to allow medical biology labs to include assay results for the presence of Omicron-specific mutations.
This procedure had the effect of causing a decrease in the results of the examination. In fact, some laboratories continued to transmit their results according to the old system – A, B, C – while others now rely on the new process, which includes the symbol D. For its part, the French public health is still publishing the results. under the old system. The complicated situation is like this now,”broken thermometer’, and this is at the worst time since Omicron has continued to spread at full speed,” Guillaume Rozier laments.
For its part, the French Public Health Authority stresses the need to solve the problem.Quickly”, to again allow reliable monitoring of the evolution of the variant.
see also – Olivier Veran: Omicron has become a ‘tidal wave’
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