Since the end of 2019, the coronavirus Sars-CoV-2 and the necessary protection against infection have been an omnipresent topic. Vaccinations, which have been possible in Germany since December 2020, cannot necessarily protect against infection, but they are intended to ensure that a kind of “immunity wall” is built. This should make possible further infections with the virus less severe. This helps to reduce the number of hospital stays and deaths from Covid-19 and thus relieve the burden on the health system. So-called breakthrough infections could be partly responsible for the development of such immune protection. These are infections that people get despite being vaccinated.
A research team from the La Jolla Institute for Immunology (LJI) has now investigated how the combination of the Covid-19 vaccination with a breakthrough infection affects the virus defense. To do this, they examined the so-called T and B cells. These immune cells have the task of recognizing and fighting pathogens such as viruses. If a person falls ill with Covid-19, the cells can look like the one in the photo. The cell is heavily covered with virus particles (yellow). The immune cells have to identify and kill these infected cells.
In order to be able to make statements about a change in the infected cells, the researchers analyzed blood samples from vaccinated subjects before and after a breakthrough infection. They found that the T and B cells were better able to recognize and fight the Sars-Cov-2 pathogens after a breakthrough infection. The increased effect of the immune cells was also visible in the Omicron and Delta virus variants.
For the LJI research team, this suggests that breakthrough infections can contribute positively to building a wall of immunity. The results could help improve vaccinations for future Covid-19 infections and other diseases.