In Germany, the case in a retirement home in Leichlingen caused a stir, in which several people had tested positive for SARS-CoV-2. But also in Austria, according to media reports, there are currently cases in which people test positive for SARS-CoV-2 despite a complete vaccination and also contract Covid-19.

The German news magazine Profil reported that an Austrian general practitioner recently stated that among his patients he had the “first two 80 plus patients with full immunization who are now symptomatically ill with Covid-19”. In addition, an 86-year-old is said to have suffered from Covid-19 and died despite being fully vaccinated with the BioNTech vaccine. Similar cases are known from the Vienna General Hospital.

But this is not the only news that again raises doubts about the usefulness of the vaccination campaigns against Corona: Certain SARS-CoV-2 variants can evidently escape an existing immunity through vaccinations or a past illness. If evolutionary pressure is exerted on the virus through medical measures such as vaccination, altered virus variants can can escape the medical “attack”. This is also known in the specialist field by the term “escape mutation”.

Scientists from the Leibniz Institute for Primate Research in Göttingen examined the effectiveness of the vaccines from BioNTech/Pfizer and Moderna against ten globally circulating virus mutations of the SARS-CoV-2 pathogen. The result of the study , which appeared in the journal Cell, showed that certain SARS-CoV-2 variants such as the British, Danish and others could be neutralized by antibodies. With the South African variant B.1.351 and the Brazilian P.1, the neutralization by antibodies was hardly effective. Study author Stefan Pöhlmann stated in a press release: “However, it is possible that a vaccination or a survived SARS-CoV-2 infection protects less well against the SARS-CoV-2 variants B.1.351 and P.1 than against the original virus.”

These findings are likely to raise doubts as to whether herd immunity can be achieved through vaccination. Pharmaceutical representatives such as Albert Bourla, the head of the US pharmaceutical company and vaccine manufacturer Pfizer, have already stated that vaccination is still one of the “most powerful tools” suggesting that a third dose of booster within twelve months and then an annual vaccination could be on the cards.

It is well known that no vaccination provides 100 percent protection. However, the pharmaceutical manufacturers have promised that the vaccines from BioNTech/Pfizer, Moderna and AstraZeneca would be exceptionally effective. It was therefore assumed that this would rarely occur with the new Corona vaccines, since up to 95 percent of infections are to be prevented. In countries like Israel, which have a high vaccination rate, this was already be shown. But it also revealed that for a certain part of the population no protection is obtained through vaccinations – especially in the particularly endangered people from the high-risk group who are prioritized in the case of mass vaccinations.

Strong evidence of this is provided by a preliminary study by virologists at the University Hospital Düsseldorf, whose expert opinion is still pending. The scientists analysed blood samples from 176 people, of whom 93 were younger than 63 years and 83 were older than 80 years. All subjects had received full vaccination with the BioNTech/Pfizer vaccine. Both after the first and after the second vaccination, the virologists analysed the proportion of IgG and neutralizing antibodies.

The results, however, were rather sobering: the younger test participants had stable antibody titers, but around 31 percent of the subjects in the over 80-year-olds had not produced any neutralizing antibodies. According to the study author Ortwin Adams, head of virological diagnostics in Düsseldorf, one of the weaknesses of the study is that they only examined part of the immune response, but not the cellular defence in the form of so-called T cells: “We did not measure the cellular immunity, only the antibodies. However, the two usually correlate.”

The cellular immune response is likely to decrease with age. According to the study, almost a third of the high-risk group did not develop complete protection against SARS-CoV-2 despite a full vaccination. Although only one vaccine has been investigated, it can be assumed that vaccinations with other vaccines will produce similar results.

In this case, however, the problem seems to be neither the specific vaccine nor the mutations against which it might be less effective, but rather a phenomenon called immunosenescence: With increasing age, the functionality of the immune system declines, older people become infected more easily, and so too vaccinations generally do no work well in these cases.

Although the phenomenon of immunosenescence has been known in medicine for decades, it has only been an issue in the Corona crisis since the beginning of mass vaccinations. One of the reasons for this is probably that people over 80 years of age, who belong to the particularly endangered age group, were significantly underrepresented in the clinical studies prior to the emergency approval of the vaccines, or all people from 65 to over 80 years of age were often grouped together.

According to Adams, it is important to be educated that people can still get infected despite being vaccinated. “Experience from all countries with a high vaccination rate suggests that serious cases and deaths will decrease significantly as a result. But you have to know that you can possibly become infected despite being vaccinated.”

According to Adams, it may be necessary for seniors to need a third vaccination as early as the fall to keep their antibody levels as high as possible.