The goal of the COVID-19 vaccine is to prevent severe illness. This is achieved by stimulating the formation of so-called memory cells of the immune system, such as B and T cells. These cells are typically long-lived and reside in the bone marrow, bloodstream, and lymph nodes. They monitor whether a person is exposed to a pathogen. If the pathogen is detected, these memory cells are quickly activated and stimulate the immune response. In this way, the infection is effectively fought before it spirals out of control and causes severe illness.

Studies have shown that COVID-19 mRNA vaccines generate high numbers of memory cells. With the emergence of the delta variant of the coronavirus, it has become clear that the number of memory cells generated by both the mRNA vaccines (Pfizer and Moderna) and the adenovirus-based vaccines (J&J/Janssen) is sufficient in most cases to prevent severe illness. These results would therefore not justify a booster vaccination.

A second goal of vaccination, however, is to prevent any kind of illness, meaning that vaccinated individuals do not even experience a mild or asymptomatic infection. To achieve this, people need to have high levels of neutralizing antibodies in their bloodstream. Neutralizing antibodies prevent the virus from attaching to and entering cells. Normally, however, the levels of neutralizing antibodies decrease over time. In this situation, a booster vaccination can stimulate B and T memory cells to produce neutralizing antibodies. The amount of detectable antibodies in the bloodstream is increased again, and the likelihood of developing the disease can be reduced.

Prof. Harmut Göbel: “At the Kiel Pain Clinic, all nurses, doctors, and other staff are fully vaccinated. I am very pleased about this. The coronavirus is in the country. If you are not vaccinated, it is only a matter of time, probably the next few months, before you become infected. The virus will use the bodies of unvaccinated individuals as a breeding ground, inserting its genetic information into their cells to multiply. This can result in severe illness with long-term consequences for the rest of one's life, or even death. Therefore, I recommend that everyone get vaccinated.”.

More information: https://www.chop.edu/centers-programs/vaccine-education-center/archived-covid-19-questions

Video: How mRNA vaccines work

How do mRNA vaccines work?