Covid-19: an analysis of the efficacy of measures introduced to combat the virus in France

Major impact of lockdowns and curfews

Their results show that the most restrictive measures, such as lockdowns and curfews, had a significant effect on reducing transmission of the virus. The first shelter-in-place measure was the most effective, reducing transmission by 84%. A 6pm curfew was more effective than an 8pm curfew (68% reduction versus 48%). Although school closures had a more limited effect, they still reduced transmission by 15%.

Rodolphe Thiébaut, professor of public health at the Bordeaux Population Health research centre¹ and leader of this study, explains that the data is consistent with other studies that have already been published, notably by the WHO. "Although estimating the number of people saved by a specific intervention is a complex exercise, all of the studies show that lockdown and vaccination had a major impact".

Within the framework of this study, the researchers also simulated different scenarios, such as one where no vaccines were available until the end of the study period (October 2021). Their data predicted 159,000 additional deaths and 1.48 million more hospitalisations in France in the absence of vaccination. That's double the number of deaths, as the epidemic caused 116,000 deaths in France and 460,000 hospitalisations (according to INSEE).

In a reverse scenario, i.e. with a vaccine available after 100 days - which was the original objective of the Coalition for Epidemic Preparedness Innovations (CEPI)² initiative - 71,000 deaths and 384,000 hospitalisations could have been avoided, i.e. almost 80% of deaths and ¾ of hospitalisations.

He highlights the necessity of taking this issue into account in the hypothetical context of a new pandemic, and therefore of implementing an optimal vaccine research and development strategy.

Lastly, it was simulated that lockdown in France one week earlier would have prevented 20,000 deaths. The public health researcher comments on these figures: "The start of an epidemic is exponential. It is obviously a major decision to confine an entire country, however these results can contribute to rapid decision-making in the event of epidemic resurgences."

It is important to remember that this is a methodological study with certain limitations that must be taken into account when interpreting the results: the age structure could not be taken into account (which may lead to an underestimation of the vaccine's effectiveness)³, nor could the closure of non-essential shops or the effect of barrier measures. The data also cannot immediately be generalised to other countries.

¹Rodolphe Thiébaut is professor of public health (biostatistics and medical computer science) at the University of Bordeaux and head of the medical information department at Bordeaux University Hospital. He leads the Statistics In System biology and Translational Medicine research group (SISTM - Inserm and the University of Bordeaux's Inria centre), dedicated to the modelling and statistical study of large-scale data, and is affiliated to the Bordeaux Population Health research centre (BPH - Inserm and University of Bordeaux unit).
²The Coalition for Epidemic Preparedness Innovations (CEPI) initiative was launched at the Davos World Forum in order to fund the development of vaccines against emerging infectious diseases and to guarantee equitable access to all affected populations.
³older people, who are at greater risk of serious illness, hospitalisation and death, were vaccinated first and have higher vaccination coverage than younger age groups.