What do the figures in France say about the effectiveness of the vaccine?
Text updated on 2022-06-14
Figures from December 2021 and January 2022 in France show that the vaccine significantly reduces the risk of severe disease and death.
We have re-analysed the data published by DREES (Direction de la Recherche, des Études, de l'Evaluation et des Statistiques) concerning the number of people affected by COVID-19 in France. We focused on the period between 1 December and 30 January 2022, which covers most of the fifth wave of infections.
Among adults aged 20 years and over (51 million people, including 8% who were not vaccinated), there were 11,296 deaths, 15,753 critical care hospitalizations and 82,636 conventional care hospitalizations during these two months. Non-vaccinated persons accounted for 42% of deaths, 50% of critical care hospitalisations and 37% of conventional care hospitalisations. Comparison of case frequencies according to vaccination status indicates that death rates are 11 times higher among non-vaccinated persons than among those vaccinated with booster. It is 16 times higher for critical care hospitalizations and 8 times higher for conventional care hospitalizations.
Distribution of cases according to vaccination status among persons aged 20 years and over, residing in France, during December 2021 and January 2022:
Total population: 50.7 million of which :
- non-vaccinated: 4.1 million (8%)
- vaccinated without a booster: 27.0 million (53%)
- vaccinated with booster: 19.6 million (39%)
Total number of conventional hospitalisations: 82,636 or 1,631 cases per Million people (abbreviated to /M below):
- non-vaccinated: 30,826 (37%) 7437 cases/M
- vaccinated without booster: 33,408 (40%) 1239 cases/M ÷ 6
- vaccinated with booster: 18 402 (22%) 941 cases/M ÷ 8
Total number of hospitalizations in critical care: 15 753 or 311 cases/M :
- non-vaccinated: 7873 (50%) 1899 cases/M
- vaccinated without booster: 5516 (35%) 204 cases/M ÷ 9
- vaccinated with booster: 2364 (15%) 121 cases/M ÷ 16
Total number of deaths: 11,296 or 223 cases/M :
- non-vaccinated: 4 802 (42%) 1 158 cases/M
- vaccinated without booster: 4501 (40%) 167 cases/M ÷ 7
- vaccinated with booster: 1,992 (18%) 102 cases/M ÷ 11
The numbers preceded by the division sign indicate how much the risk is divided for the vaccinated compared to the unvaccinated.
Furthermore, DREES data show that the incidence rate (number of positive PCR tests in relation to the population) is reduced by 44% among those vaccinated without a booster, and by 65% among those vaccinated with a booster, compared to those not vaccinated. There are therefore fewer cases of COVID-19 in vaccinated people than in non-vaccinated people. Although the vaccine was not sufficiently effective in preventing the fifth wave, it nevertheless appears to have helped slow down the transmission of the virus, and thus limit the pressure on hospital services.
Among young people under 20 years of age (16 million people, 63% of whom were not vaccinated), the frequencies of severe forms are much more limited. In total, there were 29 deaths, 906 critical care hospitalizations and 7469 HC. The rate of hospitalization in conventional care was twice as high among the non-vaccinated (5,378 hospitalizations in conventional care) as among the vaccinated (2,091 hospitalizations in conventional care). However, in terms of risk of death, there was no significant difference between the vaccinated (15 deaths) and non-vaccinated (14 deaths). Similarly, the rate of critical care hospitalisations was not significantly different between vaccinated (364 critical care hospitalisations) and non-vaccinated (542 critical care hospitalisations). The benefits of vaccination are therefore less obvious for this age group than for the rest of the population. It should be noted, however, that a more rigorous evaluation of the effects of vaccination would need to take into account the heterogeneity of risks within this population (the DREES data do not provide more detailed information on the age of individuals or on their possible comorbidities).
In conclusion, the figures for December 2021 and January 2022 in France are in line with previous analyses published in the scientific literature and are in line with the discourse of the health authorities: the vaccine considerably reduces the risks of severe forms and death.
Data published by the Direction de la Recherche, des Études, de l'Évaluation et des Statistiques (DREES) on positive cases COVID-19. The data analysed here were downloaded on 14 February 2022 from the DREES website.Data from DRESS. Accessed in February 2022.
Dagan N, Barda N, Kepten E, Miron O, Perchik S, Katz MA, Hernán MA, Lipsitch M, Reis B and Balicer RD (2021) BNT162b2 mRNA Covid-19 Vaccine in a Nationwide Mass Vaccination Setting. New England Journal of Medicine. 384:1412-1423.
Barda N, Dagan N, Cohen C, Hernán MA, Lipsitch M, Kohane IS, Reis BY and Balicer RD (2021) Effectiveness of a third dose of the BNT162b2 mRNA COVID-19 vaccine for preventing severe outcomes in Israel: an observational study. The Lancet 398:2093-2100.
Complete analysis of data published by DREES by Laurent Duret.Duret L. (2022) Impact of vaccination on the Covid19 pandemic in France during the winter of 2021/2022. Zenodo