A large-scale new coronavirus immunization study suggests that the protection against re-infection may take much longer than originally estimated. The researchers analyzed various immune response components of COVID-19 in nearly 200 patients, including meso-antibodies, B-memory cells, and two types of T-cells. The data show that these cells have a long survival period and are likely to provide years of protection after infection or vaccination.
Studies have shown that exposure to several components of the immune system caused by viruses has a long survival period. It’s not just antibodies to the virus’s hedgehog glycoproteins that can live much longer than thought. It is the B and T cells, which are essential for long-term immunity, that are likely to remain active for many years. If the data in this new study are correct, most people will receive years of protection against re-infection after infection or vaccination.
There’s been a lot of talk about COVID-19 immunity this year, and a recent flurry of scientific papers has brought good news. Some new coronavirus antibodies may disappear in as little as three months, but the meso-antibodies can last five to seven months. In addition, studies have suggested that the body’s response to T-cells of pathogens can be “strong” and T-cells can be detected after six months. These specific white blood cells for the new coronavirus can launch new defenses after re-infection.
Researchers from the La Hoya Institute for Immunology, the University of California, San Diego, and mount Sinai’s Icahn School of Medicine studied not just an integral part of the immune system, but nearly 200 patients. They studied the number of melios, T-cells and B cells in a COVID-19 survivor, and the team believes the immunity of the new coronavirus is likely to last for years, not just months.
The researchers looked at 185 men and women between the ages of 19 and 81 who survived contracting COVID-19. They took blood samples from each survivor and tracked four components of the immune system, including meso-antibodies, B-memory cells that produce more antibodies, and T-cells that kill cells infected with the SARS-CoV-2 virus.
“If you look at only one, you might really miss the whole picture,” Dr. Shane Crotty, a virologist at the La Hoya Institute of Immunology, told The New York Times.
The team found that levels of the meso-antibody were persistent and declined moderately within six to eight months of infection. But not all of the volunteers in the study had the same level of antibodies. T cells show only slow decay in the body, indicating that they last a long time. Surprisingly, the number of B-cells of memory viruses increased rather than decreased.
The slow rate of decay suggests that these cells may survive longer than originally thought, and that they may be able to launch strong defenses against re-infection. “Sterilizing immunization doesn’t happen very often — it’s not the norm,” Dr. Alessandro Sette, an immunologist in La Hoya, told the New York Times.
If the study is accurate, the immune system will destroy the pathogen when it re-infects, and then there will be time to cause any damage. “It can be terminated quickly enough, not only are you not experiencing any symptoms, but you are not contagious,” Sette said.
While researchers are not sure how long coronavirus immunity lasts based on these findings, the data suggest it could take years to lose it. “This amount of memory is likely to keep the vast majority of people from being hospitalized or developing severe illnesses for many years,” Crotty said of the data.
However, some of the infected people in the new study did not have lasting immunity after recovery. It is not clear why. The new study has not yet been peer-reviewed.