Coronavirus: For whom the vaccination works worse

Every vaccination basically works like a training session for the immune system: the immune system reacts to it through contact with replicated parts of a virus. Antibodies are formed and upon contact with the real virus, the immune system can immediately initiate defense measures so that the virus does not multiply in the body. Or at least not in full to cause serious illness.

This effect is also used in the current vaccination against Covid-19. However, not every immune system reacts in the same way – it changes over the course of life and becomes weaker. However, the body’s own defense system in older people has come into contact with various pathogens in the course of their lives and is therefore more trained to deal with them than small children, for example.

Bad immune response

In some people, the corona vaccination apparently triggers a poor or no immune response. They do not build up effective immune protection. Studies have shown that vaccinations don’t work as well in people who are taking drugs that suppress the immune system. This was emphasized by the chairman of the German Standing Vaccination Commission, Thomas Mertens.

Accordingly, people are affected after organ transplants or with cancer. The immune response depends on the extent of the immunosuppression, explained Mertens.

Weaker immune systems in the elderly

Researchers from Berlin were now able to explain why there were still corona outbreaks in old people’s and nursing homes despite two vaccinations during the course of the corona pandemic Charity to explain. The immune system of old people reacts less efficiently to the vaccination than that of younger people, said the Charité after two in the specialist journal Emerging Infectious Diseases published studies with. It is therefore particularly important that nursing staff and visitors are immunized. In addition, hygiene measures and tests remained important. In the medium term, a further booster vaccination for older people is an option in order to improve their vaccination protection.

For an investigation, the scientists worked on an outbreak in a Berlin care facility from February. In addition to 11 nurses without complete vaccination protection, around 20 residents were infected with Sars-CoV-2 in the Alpha variant (B 1.1.7). All but four of them were fully vaccinated with the Biontech / Pfizer vaccine. The four unvaccinated became so seriously ill that they had to be treated in a hospital. Only around a third of those vaccinated had symptoms such as coughing or shortness of breath. According to the Charité, two vaccinated residents died, but probably not causally of Covid-19.

Mild disease courses

“On the one hand, we can see from this outbreak that the vaccination has protected the residents of the nursing home as a whole, because the course of the disease was much milder,” says Victor Corman, deputy head of the consulting laboratory for coronaviruses at the Institute of Virology. “At the same time, the increased number of infections makes it clear that the high effectiveness of the vaccination in old people is sometimes not fully effective.”

In the second study, the research team compared the immune response to the Biontech / Pfizer vaccine in patients over 70 years of age at a family doctor’s practice with that of Charité employees, who were on average 34 years old. Blood analyzes showed that just three weeks after the first dose, around 87 percent of the younger ones had developed antibodies against Sars-CoV-2. Among the older it was only around 31 percent. One month after the second dose, almost all young people vaccinated (99 percent) had specific antibodies in their blood. Among the elderly, it was around 91 percent. In addition, the antibodies matured more slowly in the elderly, so they were less able to bind the virus.

The second important arm of the immune response, the T-cell response, was also weaker. “Our study shows that the immune response in older people is significantly delayed after vaccination and does not reach the level of young vaccinees,” summarizes Leif Erik Sander, vaccine researcher from the Medical Clinic with a focus on infectious diseases and pulmonology.

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