How long does the protection of the approved mRNA vaccines last?

This is being investigated continuously and can therefore not yet be answered conclusively. However, it is certain that the mRNA vaccines 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 delta variants. Initial studies show similar results for infections with the omicron variant.