Early studies of convalescent plasma donors showed persistence of immune activation in people with prior COVID-19 compared with historical donors (59), and early studies of long COVID showed that elevations in certain biomarkers (e.g., IL-6, TNF-α) during early COVID-19 recovery (1-2 months) were associated with the presence of long COVID symptoms at 4 months (60, 61). This evidence concerns the gene TNF and COVID-19.