Corona vaccines: a third injection after six months?

The pharmaceutical companies Biontech and Pfizer assume that a third vaccination with the corona vaccine Comirnaty, which they have developed, is required within six to twelve months of the full vaccination. “While the protection against a severe course remains high within the first six months, a decline in effectiveness compared to symptomatic courses over time and the further emergence of new virus variants are expected,” said a joint statement from the vaccine manufacturer. The companies also refer to data from the Israeli Ministry of Health. In order to maintain the highest possible protection, a booster vaccination could be helpful.

The companies are referring to data from an ongoing study of a third booster dose of the mRNA vaccine. These showed that a third vaccination six months after the second would lead to five to ten times higher neutralizing antibody levels against Sars-CoV-2 and against the beta variant, which was first discovered in South Africa. Details are to be published soon in a specialist journal. The data are now to be submitted to the US FDA and the European EMA with the aim of enabling third-party vaccinations.

An adaptation to the delta variant is also conceivable

New figures show that the delta variant can reduce the protective effect of the vaccines. According to data from the Israeli Ministry of Health, Biontech’s vaccine prevents around 64 percent of all symptomatic infections with the Delta variant. Before Delta expanded into Israel, this value was 95 percent. However, the protection against serious illnesses, which, for example, require a stay in a clinic, is still at a very high 93 percent, emphasizes the Israeli authority.

A third dose probably offers “the highest level of protective effectiveness compared to all variants tested so far, including the Delta variant,” as Pfizer and Biontech write. At the same time, the companies are also working on an adapted version of their vaccine based on the modified spike protein of the delta variant. The first study of this adapted vaccine is expected to begin in August.

It is still unclear whether the regulatory authorities share the vaccine manufacturer’s assessment. A notice from the FDA and the US health authority CDC initially stated that Americans who were fully vaccinated do not currently need a booster vaccination. But be prepared for the administration of booster doses if scientific evidence shows that they are necessary. US health officials looked into the question, but did not rely solely on data from pharmaceutical companies.

Booster vaccinations were already an issue between Merkel and Spahn

According to the federal government, the federal and state governments are also preparing for booster vaccinations. Chancellor Angela Merkel and Health Minister Jens Spahn have already spoken about it, said government spokesman Steffen Seibert on Friday. “Citizens can be sure that the federal and state governments are preparing for what needs to be prepared, namely that after an initial wave of immunization, the vaccine and vaccinations will be available and made available for refreshment,” he added.

So far, the data situation is not yet sufficient to recommend a third vaccination after six months, said a spokesman for the Federal Ministry of Health. A booster vaccination will in all likelihood be necessary. “We are now waiting for the data to be submitted, and the Standing Vaccination Commission will make a recommendation accordingly.” Leif Erik Sander, infection immunologist at the Berlin Charité, told the dpa that the immune response is likely to decline, especially in older people. For young and healthy people, however, booster vaccinations are not yet an issue.

So far there is still very little meaningful data on the long-term protective effect of the approved corona vaccine. Recently had a study in the trade magazine Nature showed that mRNA vaccines like Biontech trigger a long-lasting immune response in the body, also against different variants of Sars-CoV-2. Defense cells, the antibodies of which bind to the spike protein of the coronavirus and thus switch it off, could mostly be detected in the lymph nodes of test subjects 15 weeks after the first vaccination dose. The immune response to the mRNA vaccination is significantly more robust than that to the flu vaccination, which has to be renewed annually, emphasize Ali Ellebedy of the Washington University School of Medicine in the study. However, they had only examined the immune response for the alpha and beta variants, not for the delta variant, which is currently spreading rapidly around the world.

(With material from dpa.)