Most of those who have been through Covid-19, regardless of severity, have protective antibodies up to a year later infection, according to a study by IrsiCaixa in collaboration with the Center for Research in Animal Health (CReSA) and the Barcelona Supercomputing Center (BSC).
Scientists have observed that, although the production of antibodies is higher in hospitalized patients, their ability to block new variants of the coronavirus is more affected compared to that of asymptomatic patients or with mild symptoms, who generate fewer antibodies, but more protective against new variants of the virus. Vaccination has involved an increase in their antibody levels in all the individuals in the study, reaching very similar amounts among all of them.
For the preparation of the study 332 people have participated who have passed Covid-19, both asymptomatically and mildly, about 60%, and severely, the remaining 40%, and the neutralizing immune response has been followed for 15 months. Thus, researchers have confirmed that, in most cases, antibody levels are maintained for more than a year offering protection against COVID-19.
“What we have seen throughout this year is that protective antibodies in hospitalized patients peak in a few days after presenting the first symptoms and, subsequently, they decline in a pronounced way, until they stabilize, remaining elevated over time “, explains Edwards Pradenas, predoctoral researcher at IrsiCaixa and one of the authors of the study.
“In the case of people who have had Covid-19 in an asymptomatic or mild way, the levels of protective antibodies, although they are also sustained over time, remain lower,” he adds. The scientific staff has determined that, in the case of hospitalized patients, the quality of the antibodies is lower.
In fact, the study shows that protective capacity of antibodies against the Beta variant, which first appeared in South Africa, is lost more markedly in hospitalized patients than in people who have passed COVID-19 asymptomatically or mildly.
“Recent data suggest that, in the absence of the vaccine, 50% of the study participants could suffer a reinfection by the Beta variant of the virus, the most resistant to antibodies described so far, and this percentage would drop to 30% in the case of the original virus“, says IrsiCaixa researcher Julià Blanco.
The administration of the vaccine has allowed the antibody levels of the people participating in the study, of different magnitude depending on the symptoms, to reach comparable values.
“Although not all the people we have followed have received the complete vaccine schedule, we can say that, in all of them, their immune response against the virus has been enhanced, demonstrating, once again, the clear benefits of vaccination “, celebrates Bonaventura Clotet, director of IrsiCaixa.