Corona vaccine and delta variant: how well a third vaccination works

style="float: right; margin-bottom: 10px; font-weight: 600;"Thu 8th Jul, 2021

As of July 5, according to the Robert Koch Institute (RKI), more than half of the people in Germany have received their first vaccination. And: A total of 39.3 percent of people have also already had their second prick and are registered by the RKI as fully vaccinated. However, the delta variant of the coronavirus is on the rise, and many are wondering whether a third vaccination dose might make sense in the foreseeable future.

The problem is that the vaccines against the coronavirus all had to be newly developed and therefore one cannot fall back on long-term studies. What does exist, however, are studies in which the immune response after a vaccination is analyzed via blood sample. A new study on the Corona vaccine from AstraZeneca was recently carried out on the basis of the above-mentioned method, as reported by the portal. The result: a third vaccination with the vaccine apparently produces a high immune response.

According to reports in Der Spiegel, the AstraZeneca study also observed that T-cell responses - which show how long one is immune to a virus - were better after the third dose of AstraZeneca. However, the study by the University of Oxford and manufacturer AstraZeneca has not yet been peer-reviewed by independent researchers. In other words, the new findings on Corona vaccination and the immune response should be treated with caution for the time being. And there is something else that should be considered here.

Although the AstraZeneca study attests to a strong immune response after a third vaccination, it remains unclear whether a third vaccination is really necessary. The situation is different again in the field of mRNA vaccines from Biontech and Moderna. A new U.S. study - recently published in the journal Nature - concludes that after the second dose of vaccination with an mRNA vaccine, protection could last for years.

According to reports in Der Spiegel, it is therefore questionable whether the majority of all the people who have been vaccinated with Biontech or Moderna will even need a third Corona vaccination in the foreseeable future. What the U.S. study does not take into account, however, are even more contagious variants of the corona virus that could emerge in the future. In the U.S. study, the researchers examined the so-called memory cells of the vaccinated subjects.

Data on the third Corona vaccination with AstraZeneca, Biontech and Moderna are still very scarce. Although there are already initial studies on the overall efficacy, they do not answer the question of when or for whom a third vaccination is actually useful in individual cases. And what does the situation actually look like after a vaccination with Johnson & Johnson? After all, the vaccine only has to be inoculated once and is also supposed to be effective against the delta variant. However, it is unclear exactly how long the protective effect lasts.

Third Corona vaccination: This is what is known about the effect of Johnson & Johnson

However, Der Spiegel reports a study on Johnson & Johnson from Israel that gives indications of at least eight months of immune protection. However, just as with AstraZeneca, Biontech and Moderna, newly emerging mutations could necessitate a more rapid booster. If necessary, the individual Corona vaccines would need to be adjusted. In addition, it is important to consider that the elderly or people with specific pre-existing conditions may need a booster more quickly.Should a booster become necessary, cross-vaccination could be an option for those affected. This is because recent studies have shown that cross-vaccination is highly effective, which is why the Stiko also recommends in its latest recommendation that people be vaccinated with an mRNA vaccine after the first AstraZeneca vaccination. However, it is also possible that the individual manufacturers themselves will develop a booster vaccine that is also adapted to possible new mutations of the coronavirus.New studies such as those on AstraZeneca show that a third vaccination can induce an even stronger immune response. On the other hand, the protective effect is already very high even after two vaccinations. In this respect, the question of whether a third vaccination dose is even more effective against the delta variant cannot be answered with yes or no. The fact is that boosters may become necessary at some point.

Photo by Steven Cornfield


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