Covid: Institut Pasteur’s predictions for this summer, "favorable conditions" in 2021

Published by Laurent de Sortiraparis · Published on May 25th, 2021 at 11:29 a.m.
How could the Covid epidemic evolve this summer? A question the Institut Pasteur tried to answer to as the institution issued this Monday May 24 their projections for this summer. Hypotheses making us hope "favorable conditions" for this summer 2021, especially thanks to the decline of the epidemic and the improving vaccination. To prevent a fourth wave or a new epidemic surge, a few conditions have to be met, though.

How could the epidemic evolve by the summer? A question many French people have and to which the Institut Pasteur tried to answer with several projections revealed this Monday May 24, 2021. And they are particularly clear: "If we manage to keep up with the current pace of decline in infections and hospitalizations, until June 9 while keeping up or increasing the vaccination pace, we do not expect to see this summer a major surge in the epidemic caused by the B.1.1.7 variant ('UK') on the control conditions instated in the summer 2020".

As for hospital data, Institut Pasteur scientists consider the number of daily hospitalizations has moved from 2,000 to 700 in one month. The Incidence rate has also dropped from 350+ to 130. But first and foremost, 500,000 doses of vaccine have been given every day as this same data was around 350,000 a few weeks ago.

Projections taking many factors into account including the impact of measures currently instated, the lockdown exit pace, the vaccination campaign and even the impact of the UK variant in the country. "These scenarios are not predictions" the Institut Pasteur added. And to add: "tracjectories described depend on hypotheses made; if they do not happen, the dynamic observed could be different from projections", searchers warn at the beginning of the document.

Among these projections, less optimistic scenarios like the one where "a new epidemic surge this summer cannot be excluded", and therefore, hospitalizations could increase by June 9. "If the decline stops following the second step of the reopening calendar on May 19 and transmission rates increase again from this day forth, the epidemiologic situation over the summer is more than uncertain", scientists explain. They also speak about the pivotal period between late May and early June: "the size of this new surge might depend on transmission rates over the second half of May and June, the vaccination pace and hypotheses as for the increasing transmission of the B.1.1.7. variant", they go on.

Projections that still need to be reviewed, the Institut Pasteur wishing to remain cautious on the different scenarios raised. Yet, they give a bit of hope "in all explored scenarios, this new surge might be weaker than the third wave".

Life to get back to normal starting this Fall - according to projections

Is France to soon reach the end of the tunnel and exit the Covid crisis? Of course, according to many scientists and doctors thinking life is to get back to normal between the summer and the Fall 2021. As for Institut Pasteur, this Tuesday April 6, they even go further in a study featuring several likely crisis-exit scenarios, depending on the vaccination level. And their predictions are clear: to life to really get back to normal this Fall, vaccination must reach a very high rate.

Therefore, according to Institut Pasteur forecasts, vaccinating 90% of people aged 65+ and 70% of people between 18 and 64 years of age is not enough to let go of the health guidelines by the Fall. Because of the UK variant – far more contagious – that, according to the Institut, makes the R-0 increase to 4 this Fall, which is well-above the threshold reached when the first wave peaked in March 2020. Also, because the low immunization rate only involves 20% of the French. Predictions that go all the way up to establishing the number of daily hospitalizations and suggest there will be over 1,000 of them.

Even in the most optimistic scenarios, the current vaccination intentions of the French population could not enable making controlling measures completely softer. If possible, vaccinating children could help reach this goal”, Institut Pasteur explains. Yet, despite this scenario, living under a cover with lockdown and curfew would no longer be useful: “it would be necessary to keep controlling measures and reduce the transmission rates in the overall population by 15-27% compared to the scenario of lifting measures. As a comparison, during the March-May 2020 lockdown, the transmission rates have been cut off by 80%”, scientists continue.

What about herd immunity? It remains reachable, the Institut thinks. “If the vaccination campaign only applies to the adult population, for R0=4, it would be necessary that over 90% of adults be vaccinated to consider lifting controlling restrictions”, the scientists explain. And if vaccines are effective and safe for children, these data could be reviewed downwards: “vaccinating 0-64-year-old by 60-69% and 65+ by 90%” would enable to reach the goal. A major stake then for the government that must convince as many people as possible to get vaccinated.

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