Existing antibodies against other coronaviruses in the human body can serve as a new defense against SARS-CoV-2. This is evidenced by a new study by Spanish scientists published in the journal Nature Communications.
Of the vast family of coronaviruses, seven affect a person. Most of them cause only a cold. There are three exceptions: MERS-CoV, SARS-CoV, and SARS-CoV-2.
A team of specialists led by researchers from the Barcelona Institute of Global Health for seven months — from March to October 2020 — studied the level of antibodies in the blood of 578 employees of the Clinical Hospital of Barcelona. They measured the level and type of antibodies to six different SARS-CoV-2 antigens and the presence of antibodies to four more coronaviruses — those that cause SARS in humans.
The researchers found that most of those who had the coronavirus were infected at the beginning of the pandemic. The percentage of participants with antibodies to SARS-CoV-2 increased slightly — from 13.5 to 16.4 percent, while the number of antibodies remained constant or even increased.
In addition, the work of Spanish scientists supports the theory that antibodies against SARS-causing coronaviruses can provide cross-immunity against COVID-19. In patients who underwent COVID-19 in a mild form, IgG and IgA antibodies titer to other coronaviruses was higher than in patients with developed symptoms. Among those who did not become infected with SARS-CoV-2, there was also a tendency to increase such antibodies.