However, against the Omicron of Covid-19, which currently dominates in Switzerland, the protective effect against infection appears to be reduced. In contrast, the mRNA vaccines still offer a high level of protection against a severe course of disease, including against Omicron.
Protection from vaccination declines over time. Especially in older persons. A booster vaccination helps to increase the effectiveness again. The booster vaccination protects against severe infection for at least 6-9 months.
Since August 2022, a booster vaccine from Moderna adapted to Omicron has been authorized in Switzerland (Spikevax® Bivalent Original/Omicron (mRNA-1273.214)). In studies, this vaccine resulted in a stronger immune response against the Omicron variant (subvariants BA.1 and BA.4/5) than the original vaccine. It is not yet known whether the adapted vaccine also provides better protection against infection and a severe course of disease caused by Omicron, and how long the protection lasts.