[Immunity to SARS CoV-2 - strengths and weaknesses].

In an unprecedented collaborative effort, basic and clinical scientists have provided us with an effective COVID-19 vaccine within less than one year after SARS CoV-2 emergence. Virus or vaccine induced immunity may offer different degrees of protection against infection, transmission and pathology (disease). Immunity decides on the outcome of COVID-19, both at an individual as well as a population level. In this literature analysis, emphasis is put first on the gold standard for evaluating human antiviral immunity: data from high quality, well-designed trials centered on patient outcome as clinical endpoint (morbidity, e. g. severe COVID-19). Next, case reports or case series on humans with inborn errors of immunity (IEI) may provide unique insights into human CoV-2 immunity. Surrogate markers in blood (e. g. antibody titers) are extensively employed for the evaluation of SARS CoV-2 immunity, but are not useful. SARS CoV-2 antibody titers neither indicate local immunity in the nasopharynx/respiratory tract nor do they reliably reflect systemic immunity. Systemic and tissue resident SARS CoV-2 specific effector and memory T-cells are key to immunity but cannot routinely be measured in blood. Based largely on clinical data, this literature analysis suggests that antiviral immunity against Coronaviruses including SARS CoV-2 is waning significantly over time regarding infection and transmission protection. However, in individuals who have recovered from infections with human Coronaviruses (including SARS CoV-2) or been vaccinated against SARS CoV-2, immunity is robust in its most critical quality: protection against pathology/severe disease. Thus, immunologists see the glass half-full and envisage the transition of COVID-19 from an epidemic to an endemic state with semiannual peaks of incidence but, most importantly, protection from severe COVID-19 or death in the vast majority of individuals (as observed in other human Coronavirus infections).

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Professor Niehues hat Autorenhonorare von uptodate.com (Wellesley, Massachusetts, USA) und Reisekostenerstattungen während seiner Beratertätigkeit für die European Medicines Agency (EMA), steering committees der PENTA Paediatric European Network for Treatment of AIDS (Padua, Italien), die Juvenile Inflammatory Cohort (JIR) (Lausanne, Schweiz) erhalten.