Vaccines against coronavirus disease 2019 (COVID-19) Efficacy comparison, safety aspects, and current challenges

Several RNA-, vector-, and protein-based coronavirus disease 2019 (COVID-19) vaccines are currently available in order to achieve high titers of neutralizing antibodies against the spike protein as well as strongly activated CD4+- and CD+ T-cells. However, there are formulation-specific advantages and disadvantages with regard to physicochemical stability, spectrum of adverse effects, need for adjuvants or adaptability to potentially novel viral variants. Whereas children and pregnant women now have access to COVID-19 vaccines, it often remains difficult to achieve sufficient cellular and humoral immunity in heavily immunocompromised patients. As a consequence, innovative vaccines need to be developed for these patients. Undoubtedly, reports addressing, e.g. vaccine-associated myocarditis or thrombotic thrombocytopenia have led to uncertainties; however, vaccination remains the most important cornerstone in containing the pandemic.