The immune system of older people reacts slower and less versatile to the flu vaccine than younger people. As a result, seniors are less well protected against new variants of the ever-changing influenza virus, US researchers report in the journal "Cell Host & Microbe".
Influenza viruses are constantly changing tiny structures on their surface that actually serve as a hallmark of the immune system. Antibodies dock specifically to these structures so that the immune system can recognize and neutralize the viruses.
If a pathogen is constantly changing, the immune system also develops a certain amount of flexibility. The genes of certain immune cells - the B cells - mutate so that they produce different antibody variants and are armed against different forms of the pathogen. The researchers now investigated how this process changes with age.
Immune system gets stuck in the past
To do so, they compared how B cells from younger (22 to 64 years) and older (71 to 89 years) adults respond when the subjects were vaccinated with different influenza viruses. It has been shown that younger people's B cells continually accumulate changes in the antibody genes. In older age, this ability diminished.
In addition, the antibodies of older subjects reacted particularly strongly to historical virus variants that circulated in the subjects' childhood. The immune response to newer virus variants was much weaker. "Our findings could be used to make better vaccines and improve the protection of the elderly," says study leader Patrick Wilson of the University of Chicago (USA).
A vaccination remains the best protection against influenza, the researchers emphasize. "We do not say that people should not get vaccinated or that the current vaccines are useless for the elderly," says researcher Carole Henry, also from the University of Chicago. Rather, the goal is to further improve the vaccines.
First variants especially for older people are already developed. The immune response to these vaccines would have to be investigated in a next step. Such vaccines contain about potentiators.
Older people can halve their risk of infection with the vaccine
The Ständige Impfkommission (Stiko) at the Robert Koch Institute recommends the flu vaccine for all people over the age of 60 years. With them the danger is particularly great to develop dangerous complications in the course of a flu illness.
Last winter, the Robert Koch Institute documented 1674 flu-related deaths. 87 percent of those affected were at least 60 years old, 50 percent 80 years and older.
Even if their immune response is weaker, older people with a vaccine could halve their disease risk, reports the RKI. In addition, the disease is mild in vaccinated people.
The flu epidemic in Germany began in mid-January and the number of illnesses is currently rising rapidly. Since September 2018, according to the Robert Koch Institute, 74 people have died as a result of a flu infection. Seventeen percent of those infected with a laboratory infection had to be hospitalized.
So far, it can not be estimated how severe the flu epidemic will be this season. If you still want to be vaccinated, you should do it quickly. The immune system takes about two weeks to build the maximum protection possible after vaccination.