A recent report by the Swiss Covid-19 Science Task Force estimates that as much as 40% of Switzerland’s population may have been infected with the Omicron varient over a four-week period.
At the peak of the Omicron wave, almost 900,000 people in Switzerland tested positive for the Omicron varient over four weeks. Adding in unreported cases the total number is estimated to be three to four times this figure or around 30% to 40% of the population, said the report. The analysis does not rely only on test data. It also includes data on the amounts of SARS-CoV-2 found in wastewater.
Omicron has the ability to infect vaccinated and recovered individuals at a greater rate than Delta. However, the probability of being hospitalised after a positive test has fallen significantly in the last 12 months. The main reason is vaccination, which shows a high protective effect against severe outcomes, said the authors.
The data also indicate that the recent wave of infection has peaked. The number of people testing positive is in decline, positivity rates (the percentage of tests coming back positive) are falling and the amount of the virus in waste water is trending down.
Even if periods of higher virus circulation are to be expected in the future, the expected future burden of the disease in hospitals is expected to be significantly lower than the period before vaccination was possible, said the experts. Various studies show that after vaccination or infection, the protection against severe disease is significantly higher and longer-lasting, probably years with repeated vaccination or infection.
However, for people without previous infection or vaccination or people who cannot be protected by vaccination due to immunosuppression, there is still an increased risk of a severe course of infection with SARS-CoV-2, added the authors. In addition, little is known about which people have an increased risk of long-term health problems after infection with SARS-CoV-2 and how long such problems last after infection.
Science task force report (in German)