Because the immune system of vaccinated people always reacts to an infection with a new variant with its already developed memory: “The old, antibody-producing B cells are boosted, which form antibodies against the original form of the virus. That’s where the strongest effect is. At the same time but there is also a – smaller – amount of antibodies specifically against omicron.”
The unvaccinated person who is only infected with omicron “is of course only equipped with neutralizing antibodies against omicron – he has nothing else to boost, no immune memory.”
Fourth vaccination: A fourth vaccination refreshes the protective effect, similar to an infection after three vaccinations. “For me, however, that is not an argument to prefer the infection to a vaccination, because the infection can also have unpleasant consequences in vaccinated people – we cannot yet see the effects, for example on the brain.”
In any case, the range of antibody protection is greatest when you come into contact with other variants after a triple vaccination – be it through infections or vaccinations with variant vaccines.
Incidentally, anyone who has now had an omicron infection and – if there is a corresponding recommendation – is vaccinated for the fourth time in autumn will not damage their immune system: “On the contrary: by then the protective effect of the infection will probably have largely disappeared , but another vaccination is then a particularly good booster.”
Older people over 65 and high-risk people (e.g. immunocompromised people) can already be offered a fourth vaccination in view of the currently high number of cases after an individual benefit-risk assessment by the doctor. Weseslindtner: “But it doesn’t harm an older person to get the fourth vaccination after just four months – the amount of antibodies increases and the risk of infection decreases,” says Weseslindtner.