People who have recovered from novel coronavirus infection have immune memory to protect against reinfection for at least eight months, according to a new study that provides strong evidence for the likelihood that Covid-19 vaccines will work for long periods.
While previous studies have shown that antibodies to coronavirus decline after the first few months of infection, raising concerns that people may lose immunity quickly, the new research, published in the journal Science Immunology, puts an end to these worries.
According to scientists, including those at Monash University in Australia, specific cells within the immune system called memory B cells “remember” the virus infection and, if re-exposed to the virus, trigger a protective immune response to through the rapid production of protective antibodies.
For the study, the researchers recruited a cohort of 25 Covid-19 patients and took 36 blood samples from day 4 after infection to day 242 after infection.
The scientists found that antibodies to the virus began to decline after 20 days of infection.
However, they said that all the patients still had memory B cells that recognized one of the two components of the virus: the spike protein that helps the virus enter host cells and the nucleocapsid proteins.
Based on their analysis, the researchers said that these virus-specific memory B cells were stably present for up to eight months after infection.
Scientists believe the findings give hope about the efficacy of any vaccine against the virus, and also explain why there have been very few examples of genuine reinfection among the millions of people who have tested positive for the virus around the world.
“These results are important because they definitely show that patients infected with the Covid-19 virus do indeed retain immunity against the virus and the disease,” said study co-author Menno van Zelm, from the Department of Immunology at Monash University. and Pathology.
“This has been a black cloud hovering over the potential protection that any Covid-19 vaccine could provide and gives real hope that once a vaccine is developed they will provide long-term protection,” van Zelm said.
