Study: immunity post-Covid-19 infection lasts up to 8 months
Australian researchers have revealed that people who have been infected with the Covid-19 virus have immune memory to protect against reinfection for at least eight months.
The research is the strongest evidence for the likelihood that vaccines against the virus, SARS-CoV-2, will work for long periods. Previously, many studies have shown that the first wave of antibodies to coronavirus wane after the first few months, raising concerns that people may lose immunity quickly.
The study is the result of a multicentre collaboration led by Associate Professor Menno van Zelm, from the Monash University Department of Immunology and Pathology, with the Alfred Research Alliance between Monash University, The Alfred hospital, and the Burnet Institute.
The researchers recruited a cohort of 25 COVID-19 patients and took 36 blood samples from them from Day 4 post-infection to Day 242 post-infection.
As with other studies, looking only at the antibody response, the researchers found that antibodies against the virus started to drop off after 20 days post-infection.
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However, all patients continued to have memory B cells that recognised one of two components of the SARS-CoV-2 virus, the spike and nucleocapsid proteins. These virus-specific memory B cells were stably present as far as eight months after infection.
According to Associate Professor van Zelm, the results “give hope to the efficacy of any vaccine against the virus”. This also explains why there have been so few examples of genuine reinfection across the millions of those who have tested positive for the virus globally, he said. The research has been published in the Science Immunology journal.
