July 1, 2022

Covid: Omicron is a game-changer in hospitals, the proof in 8 graphs

SCIENCE – We have “avoided the worst”. This is how the Scientific Council analyzes the health situation, in its latest opinion of January 19. While recalling that the circulation of Covid-19 remains “very intense” due to the Omicron variant, which is very contagious and capable of reinfecting vaccinated or cured people, the researchers note that “the hospital system should hold up during the coming weeks”.

There are of course many “ifs”: the French must continue to be careful by reducing their risky contacts as has been the case since the beginning of the year. It is also necessary that the peak of cases expected in mid-January is not too delayed, in particular by the situation in schools.

If such a situation is possible when we have never recorded so many positive Covid-19 cases as in recent days, it is thanks to “a significantly lower severity of the Omicron variant and the protective effect of vaccines” .

Certainly, the variant is very contagious, including in vaccinated people. But the impact on the hospital has nothing to do with what we experienced in previous waves. To realize this, The HuffPost invites you to take a tour in 8 graphs of the impact of the Omicron variant on the epidemic and the hospital situation.

A variant that reinfects a lot…

As we know, the Omicron variant is spreading at an incredible speed in all populations, including among vaccinated people. The chart below shows how Omicron has held its own over Delta in recent weeks:

It is also known, through various analyzes in other countries, that a third dose of vaccine reduces the risk of infection, but the effectiveness is even lower than with the Delta variant.

The graph below, based on data posted online by the Drees (a department of the Ministry of Health), makes it possible to realize this. Each curve represents the number of positive PCR tests per 100,000 people depending on the variant, but also on the vaccination status.

The incredible breakthrough of Omicron is clear, even if those vaccinated and with a booster are less likely (proportionally) to be affected. We also note that the slope has been less steep since the beginning of January. At the same time, we realize that infections linked to the Delta variant are falling.

but Omicron causes less serious forms

The good news is that this explosion of cases, including among the vaccinated, does not turn into an explosion of serious forms requiring a passage in intensive care. This can be seen very well in the following graph, which compares the different waves of Covid-19 compared to the winter 2020 peak for each indicator.

If the fifth wave is without common measure concerning the cases, we see that the hospital wave has not yet exceeded that of winter 2020. Better, for resuscitation the curve drops.

And this, again, is due both to the Omicron variant and to the effectiveness of vaccines in protecting against serious forms. The graph below uses the data from the Drees, like the one for the PCR tests, except that it does not show the cases, but the number of admissions to critical care according to the variant and the vaccination status.

It must be understood that this photo at a given moment can evolve. If the cases continue to climb, it is obvious that the hospital indicators will also increase, but in different proportions.

The first thing we see is how much greater the risk is for an unvaccinated person infected with Delta than all the other categories (for the sake of readability, we have voluntarily removed certain categories, in particular vaccinated between 3 and 6 months, because they are located halfway between the different curves with and without reminder).

There has also been a recent increase in people infected with Omicron who have not been vaccinated or who have not received their booster. Conversely, the critical care admission rate for people with recall is extremely low, regardless of the variant.

A sham increase in hospitalizations

If we now look at hospital admissions in general, the pattern is different. Non-vaccinated people affected by Delta are still the most affected, but we see that Omicron is causing more and more hospitalizations, especially among people who have not been vaccinated or who have not yet had their booster.

The Scientific Council also notes this: “The impact [de la vague d’Omicron, NDLR] will be a little less marked on the occupancy of critical care beds, but will remain marked on conventional hospital beds”.

However, the curve of hospitalizations must be viewed with some caution. The number of cases of the Omicron variant is such that the virus is everywhere and can sometimes be detected in people hospitalized for a reason other than Covid-19. The Scientific Council estimated in the middle of last week that 9 to 14 million French people were infected by Omicron, an “exceptional level of infection over such a short period”.

And precisely, this can have an impact on hospitalizations in the sense that a significant part of the people hospitalized with a Covid diagnosis are not “for Covid-19”, but for another reason.

In its epidemiological update of Thursday January 20, Santé Publique France precisely details this distinction between “hospitalized for Covid” or for another cause. And what you’re seeing is that the number of people who are finding out to be positive in hospital is on the rise. Over the last week, we even see that hospitalizations for Covid are down, even if this data must be read with caution, because figures may not yet have been reported.

In detail, it is especially in the 20-39 age group that the number of hospitalizations with a positive PCR test, but for another reason, has exploded in recent weeks.

Finally, last point differentiating Omicron from Delta: the length of stay in hospital is reduced, especially in conventional hospitalization, as shown by this graph produced from data from the DREES.

See also on The HuffPost: After Omicron, what will be the future variants?