Associate Professor Menno van Zelm in his laboratory at Monash University. Credit: Monash University
Australian researchers have discovered – for the first time – that people are infected with the virus COVID-19 viruses have an immune memory to protect against re-infection for at least eight months.
Research is the strongest evidence of the likelihood that virus vaccines, SARS-CoV-2, will work for a longer period. Earlier, many studies showed that the first wave of antibodies to coronavirus disappeared after the first few months, which raises concerns that people may lose immunity quickly. This new work removes these concerns.
The study is the result of a multicenter collaboration led by Associate Professor Menno van Zelm, from the Department of Immunology and Pathology at Monash University, with the Alfred Research Alliance between Monash University, Alfred Hospital and the Burnet Institute, and published today in a prestigious journal. Scientific immunology. The publication reveals the discovery that certain cells in the immune system, called memory B cells, “remember” virus infection and, if re-stimulated by re-exposure to the virus, trigger a protective immune response by rapidly producing protective antibodies.
The researchers recruited a group of 25 patients with COVID-19 and took 36 blood samples from day 4 after infection to day 24 after infection.
As in other studies – looking only at the antibody response – the researchers found that antibodies to the virus began to decline after 20 days of infection.
However – most importantly – all patients still have memory B cells that recognize one of the two components of the SARS-CoV-2 virus, spikes and nucleocapsid proteins. These virus-specific memory B cells were stably present for up to eight months after infection.
According to associate professor van Zelm, the results give hope for the effectiveness of any vaccine against the virus, and also explain why there have been so few examples of true reinfection in millions of those who have tested positive for the virus globally.
“These results are important because they definitely show that patients infected with the COVID-19 virus actually retain immunity against the virus and the disease,” he said.
“This is a black cloud that hangs over the potential protection that any COVID-19 vaccine could provide and gives real hope that, once a vaccine or vaccines are developed, it will provide long-term protection.”
Reference: “Rapid generation of permanent B cell memory on SARS-CoV-2 spikes and nucleocapsid proteins in COVID-19 and convalescence”, author Gemma E. Hartley, Emily SJ Edwards, Pei M. Aui, Nirupama Varese, Stephanie Stojanovic, James McMahon, Anton Y. Peleg, Irene Boo, Heidi E. Drummer, P. Mark Hogarth, Robyn E. O’Hehir, and Menno C. van Zelm, December 22, 2020, Scientific immunology.
DOI: 10.1126 / sciimmunol.abf8891