Bibliografie

(eng): Protective effects of immunity against COVID-19 have been shown to diminish over time at varying speed depending on the source of immunity (infection, vaccination or a combination of both), viral variant, age and other factors. Using national-level data from Czechia, we here wanted to assess the protection afforded by vaccines and/or previous infection against severe COVID requiring oxygen support or long COVID up to 16 August 2023.\nProtection provided by the original vaccination series wanes fast but can be prolonged through the administration of booster doses, especially with the updated bivalent mRNA vaccines. Immunity after infection or hybrid immunity (from infection and vaccination) provided significantly better protection, waning more slowly over time. The protective effect of vaccines on the development of long COVID in the infected population was small.\nVaccination against COVID-19 remains an effective strategy to prevent a severe course of this illness but recent booster doses are required for a significant protection. Since hybrid immunity provides the strongest protection against severe cases, vaccination can be recommended even to individuals who have recovered from the disease. The protective effect of vaccination against long COVID, once infected, appears small.