A French study of 22.6million people over 50 years old found that vaccination reduces the chance of dying or being admitted to hospital with Covid-19 by 90 percent.
Research published Monday also showed that vaccines protect against the most severe effects of the most common virus strain, the Delta variant.
According to Mahmoud Zureik, an epidemiologist who directed the research, this means that people who are vaccinated are nine-times less likely to be hospitalized or die from Covid-19.
Epi-Phare, a scientific group established by France's health system, its national insurance fund, lAssurance Maladie, and the country's ANSM medicines agent, conducted the largest study of its kind.
Researchers compared 11.3 Million vaccinated over-50s to the same number of unvaccinated people from the same age between 27 December 2020 (when vaccinations started in France) and 20 July 2019.
The researchers found that there was a greater risk of hospitalisation than 90% after the second dose, and a similar decrease in deaths due to Covid-19. Similar results have been reported in the UK, Israel and the USA.
They stated that the vaccine's effectiveness in fighting the most severe symptoms of Covid did NOT decrease over the five-month study period. No matter if the patient received the Moderna, Pfizer/BioNTech or Oxford/AstraZeneca vaccinations, the results were consistent.
Because of insufficient patients and time required to study the effectiveness, Janssen's one-dose shot was not approved for France.
The study lasted only one month from the beginning of the French Delta variant to the end. However, the results showed that vaccines decreased the risk of serious illness and death in the over-75s by 84% and the 50-74 group by 92%.
Zureik stated that this is a short time period to assess the true impact of vaccinations on this variant. He also said that further research was ongoing into vaccine effects on the Delta variant.
Researchers compared unvaccinated and vaccinated people living in the same area to ensure the best comparison. The vaccines did not prevent people from becoming infected.
Zureik stated that avoiding serious infections was the primary goal of public health. He said that an epidemic without serious infections was not an epidemic.
The report concludes that all vaccines against Covid-19 have been shown to be highly effective and have had a significant impact on reducing the severity of Covid-19 in France's 50-year-olds. Epi-Phare's ongoing research will enable us to monitor the evolution of effectiveness over a longer time period and to better understand the effect on the Delta variant.