A new immunological study shows that antibodies to coronavirus can remain in the body for a period of at least three months. Researchers from the Lunenfeld-Tanenbaum Research Institute at Sinai Health and the Temerty Faculty of Medicine at the University of Toronto used both saliva and blood samples from COVID-19 patients. This enabled them to measure and compare the antibody levels over three months after the symptoms appeared.
Persistent antibodies in coronavirus
The team found that IgG-class antibodies that bind to the SARS-CoV-2 spike protein are detectable for at least 115 days. This represents the longest time interval measured to date. The study is also the first to show that these antibodies can also be detected in the saliva of coronavirus. That was announced by Jennifer Gommerman, who is professor of immunology at the University of Toronto and director of saliva testing efforts. Research suggests that saliva can serve as an alternative for antibody tests. Saliva is not as sensitive as serum, but it is easy to remove. The saliva test for coronavirus was developed at the University of Toronto while a team led by researcher Anne-Claude Gingras, Professor of Molecular Genetics at the University of Toronto, performed the test on serum.
The platform for detecting antibodies in the serum and the new blood test are incredibly robust. These are also suitable for assessing the prevalence of infections in the population. This creates yet another tool that medicine could use to better understand and even overcome this virus. Most people who recover from COVID-19 develop immune drugs in their blood. These are the so-called antibodies that are specific for the virus. In addition, these antibodies are useful for indicating who has been infected, whether or not they have had symptoms. A large team of scientists collaborated on the study.
Dr. Allison McGeer, Senior Clinical Scientist and Principal Investigator, and Dr. Mario Ostrowski granted access to the paired saliva and serum samples from dozens of patients for the study. The study was co-led by PhD students Baweleta Isho, Kento Abe, Michelle Zuo and Alainna Jamal. Dr. James Rini, Professor of Biochemistry and Molecular Genetics at the University of Toronto, and Yves Durocher of the National Research Council of Canada provided key protein reagents for the saliva studies. The durability of the antibody response to SARS-CoV-2 has been discussed many times in recent months. An earlier study published in Nature Medicine suggested that in some people who had the virus but did not show symptoms, the antibodies may go away in as little as two months.
This from Toronto team conducted study agrees with the results of leading immunologists in the United States in describing the antibody response as being longer lasting. Although the team admits there is a lot they don’t yet know about antibody responses to SARS-CoV-2 infections, including how long the antibodies in coronavirus last longer than that or what protection they offer against re-infection, this could be Research into developing an effective vaccine will have broader implications. This study suggests that a vaccine, if properly designed, may produce an antibody response that is just as permanent. So this can help protect the vaccinated person from the virus that causes COVID-19, said Gommerman.