How meaningful are the studies?
In order to be able to classify the results correctly, the details of the studies are important: In contrast to the approval studies, the three most recent studies are only observations. In this type of study, the participants are not randomly assigned to the vaccination group or the control group. This is problematic because, in addition to the vaccination status, there may be other important differences between vaccinated and unvaccinated people that affect testing, infection or more severe courses. In some cases, the studies have largely taken such factors into account. However, it cannot be completely ruled out that other factors distort the results.
In addition, the estimates of the effect of the vaccines are quite imprecise. The protection could possibly also be significantly smaller.
The studies also only compared the risks for vaccinated versus unvaccinated individuals. However, it is not possible to derive the absolute risk from the results, i.e. what proportion of people with or without vaccination would become infected or fall ill over a certain period of time.
What do the results mean?
The investigations confirm what has been shown in the studies on the benefits of vaccination in adults: Compared to the wild type of the coronavirus or the delta variant, the vaccination probably offers less protection against infection with omicron. However, protection against more severe courses is still high. For young people, the studies provide evidence that the vaccination protection against omicron decreases over time, but increases again with a booster. Because the children in the studies were relatively recently vaccinated, no reliable conclusions can be drawn from this data as to how much use a booster would have for them and when it might be useful.