A recent round of antibody testing suggests that a quarter of people living in the canton of Vaud have antibodies against the SARS-CoV-2 virus.
The antibody study run by Unisanté, which involves periodically testing a sample of the population, has been operating since May 2020.
The latest results, which involved testing around 1,000 people over the age of 15 during the beginning of February, when combined with those who have been vaccinated, suggest that 1 in 4 people in the canton now have antibodies against Covid-19.
The highest rates were among those aged 20-40 (27%) and adolescents (25%). And while the percentage was lower among the higher risk age group of 65+ (18%), the percentage in this age group rose to 21% when those that have been vaccinated were included.
Between 8 June 2020 (7%), November 2020 (17%) and February 2021 (25%), the percentage of the population with antibodies has risen significantly. However, between June and February Switzerland had a second wave of infections, so getting from 7% to 25% has come at significant cost in terms of lives and strain on the hospital system.
According to the authors, the current level of immunity, when combined with further vaccinations, should help to slow the epidemic and avoid a third wave. However, it is not enough to durably control it, they said. Vaccinating the population, particularly those in vulnerable groups, remains vital.
Currently, Vaud has administered 8.5 does per 100 residents according to the Federal Office of Public Health (FOPH).