All estimates of protection waned within months against reinfection but remained high
and sustained for hospital admission or severe disease. Individuals with hybrid immunity
had the highest magnitude and durability of protection, and as a result might be able
to extend the period before booster vaccinations are needed compared to individuals
who have never been infected.
Study finds no evidence to support link between ABO blood group and COVID-19 risk
Researchers from the Boston University School of Public Health in the United States say there is no evidence to support a correlation between ABO blood group and the risk of infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) or the severity of coronavirus disease 2019 (COVID-19).
The team’s systematic review of studies assessing the correlation between the ABO blood group and COVID-19 risk found that the majority are of low quality and subject to major methodologic flaws.
Furthermore, the few higher-quality studies that do exist found no association between ABO blood type and COVID outcomes adds Eleanor Murray and colleagues.