Sunday, July 16, 2023

 

Covid-19 in France : ending in June 2023?




At the end of June 2023, Santé Publique France ceased publication of the last of the statistics tracking Covid-19 prevalence in France. According the the following announcement, after a two week adjustment period, new virological surveillance statistics will be published weekly at national, regional and departmental aggregation levels. They do not say what these new statistics will be.
The stated rationale is a "favorable epidemic context." 


The announcement [fr] from geodes.santepubliquefrance.fr


Dans un contexte d’épidémie favorable, à compter du 1er juillet 2023, le cadre juridique actuellement en cours prévoit l’arrêt du traitement des données personnelles issues de SI-DEP. Par conséquent, après une période transitoire d’ajustement de deux semaines, les nouveaux indicateurs de surveillance virologique seront publiés aux niveaux national, régional et départemental à une fréquence hebdomadaire.

Les consignes de saisie spécifiques dans SI-VIC seront levées à partir de cette date, les indicateurs hospitaliers ne seront plus disponibles.

Santé publique France maintient la surveillance de l’épidémie à travers son dispositif multi-sources. Les indicateurs relatifs à la surveillance génomique, aux recours aux associations SOS Médecins, aux urgences hospitalières et aux décès resteront disponibles.

The Last Measures

The last measures I'd been tracking were of lab test results (number of tests, positive tests, prevalence of positive tests per 100 000 people in the cohort) and weekly hospital admissions for covid-19, or for something else but positive for SARS-Cov-2, by region, per 100 000 residents.


Confirmed test results

The lab test results series were of diminished interest after the changes to limit access to tests beginning a couple of months ago because the statistics were no longer comparable to those of the three years acquired thus far (which already had some consistency issues linked to policy changes). A much smaller proportion of the population was now sampled, restricted to symptomatic cases (I believe), without contact tracing.  However, as testing continued in this new policy context, a history of several weeks of comparable data was constituted, enabling inference of recent dynamics.


The following graph, shown with a logarithmic scale, then again with an arithmetic scale (same data), presents the weekly prevalence rates (per 100 k in the cohort) since the trough following the Winter wave. Notable is that prevalence is higher the older the age cohort fairly uniformly through these several months. Rates are remarkably low in children and adolescents, not only due to much lower rates of testing, but also lower rates of positivity.





It might have been interesting to see how quickly, and how far, rates would drop for a few more weeks (until all groups had fewer than 10 per 100k, for instance), particularly since there has been little booster vaccination or massive infection for six months and we don't know how persistent immunity is now.


Hospital admission rates

The hospital admissions series did indeed indicate a favorable epidemic context on the whole. In particular, admissions levels in the three June weeks were under 1 per 100k for "with-or-for." This compares very favorably to the low of 2.4 achieved in February 2023 for two weeks, between the Winter wave and the Spring surge (much lower peak to the surge, at 3.8, compared to 14.8 in mid-December). 




Considering the net number of hospitalized patients with Covid-19, the number has declined as admissions have slowed, but is far from cleared, particularly in some regions. The last three weeks average about 14 (per 100k) nationwide, contrasted with 36.6 for the three peak weeks in December 2022. Back-of-the-envelope: there are about 650 x 100k population (65 million); 650 x 14 = 9100, which, while the lowest since late November 2021, is still well above the 4500 in August 2020 and 6400 in October 2021 (pre-Omicron times).






There is great variation among regions' hospitalization rates. Ile de France had over 34 per 100k during the last three weeks published, whereas Pays de la Loire had under 3 per 100k. This is also true of rates of new admissions, to a lesser degree; it's less over in some places than in others.




Note that while the aggregate level for France (broader orange line) is declining, it is doing so much more gradually than after previous peaks. Will it continue to decline?  How far?  What level of hospitalization will be the stable, "endemic" state. 

It is disappointing to me that we will not have this statistic either to track the eventual resolution of this epidemic situation.

Corroboration with Excess Mortality

Eurostat reports, among other things, monthly excess mortality by country for the EU since January 2020.  The data through May 2023 were published July 14, 2023 (not all countries' data available, notably Italy not yet available).  There is an evident rise in France in April and May, which seems to correspond to the "surge" in positive test results and hospital admissions noted above. If so, June should fall close to 0 (or below) given that the situation in June was better than the situation in February in the statistics discussed above. I have no idea for July since we have no visibility on current prevalence or hospital admission rates.  

The following figure was screen-grabbed from the Eurostat page EU excess mortality above the baseline in May 2023





Tags: :Covid-19 France 2023 epidemic monitoring

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