What drives fatal cases of COVID-19 in vaccinees?. What drives fatal cases of COVID-19 in vaccinees?

SARS-CoV-2 breakthrough infections of vaccinees are a currently increasing issue. To determine the causes of death, histological organ alterations, and the viral spread in relation to demographic, clinical-pathological, viral variants, and vaccine types. In a comprehensive retrospective observational cohort study, deceased with proven SARS-CoV-2 infection after vaccination that died between January and November 2021. Collections of 29 vaccinees which were analyzed in comparison to 141 non-vaccinated control cases. Autopsies were performed in 16 partially and 13 fully vaccinated individuals. Most patients were aged and suffered from several relevant comorbidities. Real-time RT-PCR (RT-qPCR) identified a significantly increased rate of generalized viral dissemination within the organism in vaccinated cases versus non-vaccinated cases (45% vs. 16%, respectively; P = 0.008). Vaccinated cases also showed high viral loads reaching Ct-values below 10 especially in the upper airways and the lungs. This was accompanied by high rates of pulmonal bacterial or mycotic super infections and the occurrence of immunocompromising factors such as malignancies, immunosuppressive drug intake or decreased immunoglobulin levels. All these findings were particularly accentuated in the partially vaccinated cases compared to fully vaccinated individuals. Fatal course after vaccination occurred in only 14% of all COVID-19 deceased in Augsburg. In conclusion, fatal cases of COVID-19 in vaccinees were rare and often associated with severe comorbidities or other immunosuppressive conditions. Interestingly, we could observe a striking virus dissemination in our case study which may indicate a decreased capability of viral elimination in patients with an impaired immune system. However, the potential role of antibody-dependent enhancement has also to be ruled out in further studies.