Abstract
Individual variations in the immune response in Covid-19 infection or after vaccination and quantitative changes with time
Pronounced individual differences in immune responses following a SARS-CoV-2 infection or COVID-19 vaccination have been noticed. Importantly, an early and profound T cell response to the virus with the production of high amounts of interferon-gamma (IFN-γ) and interleukin-2 (IL-2) and low amounts of tumor necrosis factor-alpha (TNF-α) results in asymptomatic or mild disease, in contrast to what happens in patients getting seriously ill. In order to develop efficient vaccines and targeted immunization schedules, it is important to measure T cell responses and the antibody production induced by the various vaccines, since the immune response depends on not yet fully defined genetic properties, age, comorbidities, used medication, etc. The strongest recall is seen in convalescent persons after vaccination (‘hybrid immunity’). Because of waning of the immunity and the continuous emergence of virus variants, regular repeat vaccinations and the development of stronger second-generation vaccines, maybe with the recognition of a more extended antigen spectrum, appear necessary. Special attention should be given to high-risk patients.