Most people are adequately protected from Covid-19 by a corona vaccination – at least from a serious course of the disease. But there may be exceptions for older people. Researchers have investigated why this is so.
the essentials in brief
- Researchers at the Berlin Charité have found an explanation for why there are still corona outbreaks in old people’s and nursing homes despite double vaccinations.
The immune system of old people reacts less efficiently to the vaccination than that of younger people, said the Charité after two studies published in the journal “Emerging Infectious Diseases”. 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.
Vaccinated nursing home residents contracted Covid-19
For an investigation, the scientists worked up an outbreak in 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.
“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 vaccine is sometimes not fully effective in old people.”
Older people make poor antibodies
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, 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,” sums up Leif Erik Sander, vaccine researcher from the Medical Clinic with a focus on infectious diseases and pulmonology.
For whom the immune protection could also fail
The Standing Vaccination Commission (Stiko) also assumes that a number of people have not built up effective corona immune protection despite a complete vaccination. The Stiko chairman Thomas Mertens told the newspapers of the Funke Mediengruppe (Online Thursday / Print Friday): “There are now several studies that show that vaccination against Covid-19 does not work so well in people whose immune system is slowed down by drugs as with others. ” The immune response is worse or fails completely.
People who have had an organ transplant or, in some cases, cancer patients are also affected. In such cases it is important to reduce the risk of infection in the environment through vaccinations as much as possible. “This is called the cocoon strategy,” says Mertens. In rheumatism patients too, the immune response is at least reduced, depending on the type of immunosuppression. At the moment it is not yet possible to estimate how large the group of patients is who, despite having been completely vaccinated, had no or insufficient immune protection. “But we have to assume that these are not just isolated cases.”
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