Health care workers who had recovered from coronavirus retained antibodies that prevented reinfection for up to eight months, according to studies conducted in Australia and South Korea. Results of the Australian study suggest the immunity might last even longer.
Memory B cells were found in all Australian study participants. The cells "remember" viral proteins and can trigger rapid production of antibodies when re-exposed to the virus for months after initial infection, according to the study.
The South Korean study also showed that eight months after asymptomatic or mild COVID infection, patients had high rates of serum antibodies. Previous contradictory research reported antibodies fading after 20 days, but variations in testing and manufacturing could be responsible for the difference, study authors said.
"These results are important because they show, definitively, that patients infected with the COVID-19 virus do in fact retain immunity against the virus and the disease," said senior author Menno van Zelm, Ph.D. It gives real hope that, once a vaccine or vaccines are developed, they will provide long-term protection, he said.
SOURCE: University of Minnesota December 23, 2020