An immune system that has been trained by previous seasonal colds caused by coronaviruses is not only better prepared for an infection with SARS-CoV-2, it also helps to build up vaccination protection.
A team led by the Tyrolean researcher Daniela Weiskopf, who works in the USA, has now shown in the journal “Science” that “this cross-immunity actually leads to a better immune response after the vaccination,” she explains.
Effect of low vaccine dose analyzed
As part of the study, the team analyzed the immune response to the Moderna vaccine. In Austria, a little more than a million vaccine doses were administered up to the beginning of September, which makes up a share of just under ten percent. The primary goal was to find out how long the immune response lasts in people who have received a lower amount of active ingredient. The scientists examined samples from people who received only 25 micrograms of the vaccine twice as part of a clinical study. A dose of 100 micrograms has been approved by the US health authorities.
They found that both T helper and T killer cells reacted strongly to SARS-CoV-2 for at least six months after the low vaccine dose – even in older people who were vaccinated. Compared with people who have been through a Covid 19 infection, the reaction of the immune system, including the antibodies specifically tailored to the pathogen, was also strong.
The team also found that people with cross-reactive T cells – who previously had a coronavirus-induced cold – also developed a significantly stronger T helper cell and antibody response after receiving both vaccine doses. This could help the immune system react more quickly when dealing with SARS-CoV-2.