Collective immunity is today far from being acquired in France. Estimated at 10% in large cities, the rate should be 50% to achieve this phenomenon. Thanks to this strategy, Sweden could have contained the coronavirus.
What is collective immunity?
Collective immunity is defined by the Institut Pasteur as being ” percentage of a given population that is immune / protected against infection from which an infected subject introduced into that population will transmit the pathogen to less than one person on average, effectively bringing the epidemic to extinction “. This is therefore a theoretical percentage of the population that must be immunized to stop the spread of the virus. Public Health France and the Institut Pasteur carried out a seroprevalence study (evaluation of the number of people exposed to the virus and who develop antibodies). Currently, Île de France accounts for only 10% of the population possessing antibodies specific to the virus, a percentage recurring in large cities. The least exposed areas show just over 3%. It would take 50% to achieve collective immunity. According to this study, France is therefore far from achieving collective immunity.
Sweden, an example of collective immunity
In March, the country chose not to confine the population, unlike the majority of Europe. Shops, schools, restaurants and bars have not closed. The situation was contained on its own due to the diligence of the inhabitants who scrupulously respected barrier gestures such as social distancing and hand washing. They fled bars and restaurants and avoided regrouping. Despite the increase in positive cases and deaths at the start of the year, the country does not seem to be undergoing a second wave. Since mid-August, Sweden has recorded 150 to 300 cases per day for 10 million inhabitants, or 20 to 47 times less than in France. Over the past two weeks, France has counted 186 contaminations for 28 in Sweden (out of a panel of 100,000 people). “ It seems that the Swedes have acquired some immunity against the virus. This immunity, added to the barrier gestures, is enough to keep the disease under control. The epidemic may have been contained », Explains Danish expert Kim Sneppen.
