This is being investigated continuously and can therefore not yet be answered conclusively. However, it is certain that the protect against severe Covid-19 disease after several months with an efficacy of over 90 percent. Nevertheless, it can be observed that the vaccination protection tends to decrease over time. Especially in older persons. A complete vaccination with booster vaccination helps to keep the vaccination protection high. These observations refer to infections with . Initial studies show similar results for infections with the omicron variant.