Complement, a major component of the immune system, could influence COVID-19 disease severity. Researchers also found that people with age-related macular degeneration—an eye disease caused by overactive complement—and common coagulation disorders like thrombosis and hemorrhage are at greater risk of developing severe complications and dying from COVID-19.
Among 11,000 COVID-19 patients with suspected viral infection, the researchers found that over 25% of those with age-related macular degeneration died, compared to the average death rate of 8.5%. Roughly 20% of the people with the eye disease required intubation. The higher death and intubation rates could not be explained by differences in the patient’s age or sex.
Researchers then examined how gene activity differed in people infected with coronavirus. Their findings revealed a signature in COVID-19 patients that were indicative of how the virus might engage and induce the body’s complement and coagulation systems. The connection with complement suggests that existing drugs that inhibit the complement system could help treat patients with severe COVID-19. The study, published in the journal Nature, was partly funded by NHLBI.