Anyone who is currently thinking about a second booster dose of the corona vaccination can quickly lose perspective: the advice from politicians, authorities and the Standing Vaccination Commission (Stiko) differs. Yes what now?

Stiko, which is responsible for vaccination recommendations in Germany, has so far only considered a second booster vaccination to be useful for parts of the population: for example for people over the age of 70, patients with a suppressed immune system, nursing home residents and staff in medical facilities. Other experts have backed Stiko on this issue in recent months.

Federal Minister of Health Karl Lauterbach (SPD), on the other hand, keeps pushing for more four vaccinations and recently brought them into play for all healthy adults. Then there are two EU authorities: ECDC and EMA called on the member states to offer second boosters from the age of 60. Stiko boss Thomas Mertens then announced that the committee would comment “relatively soon” on a possible extension of the existing recommendation.

If you want to enjoy the summer without risk of illness, he would also recommend the second booster vaccination – “in consultation with the family doctor, of course” – for younger people, Lauterbach recently told the “Spiegel”. With the second booster vaccination you have “a completely different security”. He argues with a significantly reduced risk of infection for a few months and a significantly lower long-Covid risk.

The virologist Mertens told the “Welt am Sonntag” that he did not know any data that justified Lauterbach’s advice. “I think it’s bad to make medical recommendations under the motto ‘a lot helps a lot'”. The EU authorities ECDC and EMA stated that there is currently no clear epidemiological evidence to support the administration of second boosters in immune-healthy people under the age of 60 – unless patients have health problems.

From the point of view of several immunologists, the three corona vaccinations previously recommended by Stiko are sufficient for healthy adults under 60 to build up a stable immunological memory. It usually offers at least protection against serious illness, hospitalization and death. However, even dose four does not bring absolute, long-lasting protection against infection for this group. Carsten Watzl, Secretary General of the German Society for Immunology, advises anyone who no longer wants to risk infection before going on vacation, for example, to protect themselves with a mask, distance and contact reduction. Epidemiologist Hajo Zeeb also assumes that the second booster vaccination for under 60-year-olds will only have a small advantage, especially if people have also been ill in the meantime.

It is by no means irrelevant. After all, not only is an increase in the incidence of infections expected again for the autumn, but also vaccines that are adapted to Omicron. So there should be another major vaccination campaign. However, it is currently uncertain which mutations the virus will have by then and for whom renewed vaccination recommendations will then be made.

But what can be said: According to Stiko member Christian Bogdan (University Hospital Erlangen), vaccination intervals of several months have proven to be advantageous for the strength of the immune response triggered and for the resulting protection period. “It is particularly important that a booster vaccination – i.e. the third vaccination – takes place at a significant distance from the second vaccination”, ideally not earlier than six months later. This also applies to a possible second booster. This distance ensures an increase in the immune response. However, if you vaccinate into an ongoing immune response, the effect is greatly weakened.

Stiko member Bogdan says that there have been no comprehensive immunological studies for the Covid vaccines on the question of the possible harm of additional, clinically unindicated vaccinations. Some experts point out that repeated vaccinations against smallpox or influenza, for example, are not known to have any negative effects – nor in the individual cases in which people were vaccinated against Covid-19 several times.

Even if it is unsatisfactory: At the moment there is no general answer to this question. It also depends on how well the individual’s immune system responded to the first three vaccinations. The immunologist Andreas Thiel from the Berlin Charité says that for “a few” people under 60, the fourth vaccination could be essential – but you can’t easily recognize it. For most in this age group, however, a fourth dose is not really essential. “Everyone has to answer that question for themselves.”

However, your own family doctor can help with the decision. The Stiko is legally responsible for vaccination recommendations, and many doctors also follow their advice. However, physicians may inject a second booster even without a Stiko recommendation.

Apart from the question of more four vaccinations: Measured against the previous Stiko recommendations, there are some vaccination gaps. In a July report, the Robert Koch Institute stated that around 1.3 million people over the age of 60 and around 7.9 million adults under the age of 60 still had to refresh their vaccination protection with at least one vaccination. Around 1.9 million people over the age of 60 and around 7.3 million adults under the age of 60 have not yet received a vaccination.

The Hamburg intensive care physician Stefan Kluge reported on Twitter that, unfortunately, risk patients with incomplete corona vaccination series were being admitted again and again: recently, for example, a 90-year-old infected with Sars-CoV-2, who had only been vaccinated once. “These vaccination gaps should now be closed,” he appealed.