New data reveals that COVID immunity lasts up to 8 months

Menno van Zelm

Associate Professor Menno van Zelm in his laboratory at Monash University. Credit: Monash University

Australian researchers have revealed – for the first time – that people who have been infected with COVID-19 viruses 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 subsided after the first few months, raising concerns that people may lose immunity quickly. This new work alleviates those 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 prestigious newspaper, Scientific Immunology. The publication reveals the discovery that specific immune cells, called memory B cells, “remember” the virus infection and, if challenged again, through re-exposure to the virus, trigger a protective immune response through the rapid production of protective antibodies.

The researchers recruited a cohort of 25 patients with COVID-19 and collected 36 blood samples from them from day 4 after infection to day 242 after infection.

As with other studies – looking only at the antibody response – the researchers found that antibodies against the virus started to drop after 20 days after infection.

However – most importantly – all patients continued to have memory B cells that recognized one of the two components of the SARS-CoV-2 virus, the peak and nucleocapsid proteins. These virus-specific memory B cells were present stable up to eight months after infection.

According to associate professor van Zelm, the results give hope to the effectiveness of any vaccine against the virus and also explains why there were so few examples of genuine reinfection among the millions of people who tested positive for the virus worldwide.

“These results are important because they definitely show that patients infected with the COVID-19 virus do in fact maintain immunity against the virus and the disease,” he said.

“This has been a black cloud hovering over the potential protection that could be provided by any COVID-19 vaccine and gives real hope that once a vaccine or vaccines are developed, they will provide long-term protection.”

Reference: “Rapid generation of durable B cell memory for the peak of SARS-CoV-2 and nucleocapsid proteins in COVID-19 and convalescence” by 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