Two studies published yesterday demonstrate that COVID-19 immune responses last as long as 8 months, although the authors focus on different reasons.

The first study, published in Science Immunology, followed a small cohort of Australians from day 4 to day 242 after infection. All patients demonstrated the presence of memory B cells—immune cells that “remember” viral proteins and can trigger rapid production of antibodies when re-exposed to the virus—as long as 8 months after initial infection.

The second study investigated antibody responses in 58 confirmed COVID-19 patients in South Korea 8 months after asymptomatic or mild SARS-CoV-2 infection, finding high rates of serum antibodies. These results, published in Emerging Infectious Diseases, is contradictory to both the first study’s antibody data and previous research that showed antibodies waning after 20 days, but the authors suggest that variations in immunoassay test characteristics and manufacturing may be responsible for the difference.

Source: Two studies find that COVID-19 antibodies last 8 months | CIDRAP