Technology The vaccine has been useful against the Covid

The vaccine has been useful against the Covid

Mathilde Fontez, editor-in-chief of the scientific magazine Epsiloon today comes back to what we have been feeling for the past few days: the end of the rebound from the fifth wave of Covid. All the indicators are down, we are in the process of going back below the bar of 1,000 new hospitalized patients per day… Time to take stock.

franceinfo: Was the Covid-19 vaccine really effective?

Mathilde Fontez: This is a question that can be asked as the Omicron variant has spread rapidly since the end of 2021. And the contaminations still remain quite high today: 50,000 new cases per day on average, all the same. But there is no doubt: it would have been much worse without the vaccine.

A study, which was conducted in the United States, clearly establishes this. This study is distinguished by its scale: it brings together data from 80% of the American population, 300 million people, over the whole of 2021. It was therefore the Alpha and Delta variants. 30 million cases were counted in 2021, and nearly 440,000 deaths.

What would have happened if the population had not been vaccinated? The researchers were able to do the test, because vaccination coverage varied widely from place to place in the United States. They made comparisons.

So what, assessment?

The result is that each additional 10% of the population vaccinated, with at least one dose, reduces the mortality rate by 8%.This means that mass vaccination – the passage from 10 to 60% of vaccinated people – has reduced mortality by 75%.

It is recalled that in France, 80% of the population has a complete vaccination. And the vaccine has also reduced the incidence rate, the number of new cases: it is reduced by 7% for every 10% vaccinated. The figures speak for themselves: we are close to the evaluations that came out of clinical trials, carried out at the time of the development of vaccines.

Can these figures be extrapolated to 2022, with the arrival of Omicron?

Not directly, but epidemiologists expect the trends to be the same. Omicron is more contagious, less lethal. But he still kills. In France, we are only now going back below the bar of 100 deaths per day. And the risk of death remains much higher in the unvaccinated, or in people who have not had a booster for 6 months.

A study carried out in Hong Kong, from January to March, showed that it is divided by 2.5 for people who have received a dose of vaccine. And by 33 for those who received 2 doses. The appearance of Omicron may have given the impression that the vaccination did not help much. But it is far from being the case.

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