How long do antibodies last after suffering from COVID-19 and which generates better defenses against the new variants

Scientists continue to advance various studies with the aim of better understanding the body’s reaction to the SARS-CoV-2 virus that causes COVID-19. In the last hours, a new analysis conducted by a team of Spanish researchers which accounts for the protection generated by those who have suffered from the disease. They concluded that the duration of the antibodies in most of them can be up to a year after symptoms, although the quality of the immunity generated depends on the severity of the condition suffered.

The research was carried out by a team of IrsiCaixa, in collaboration with the Animal Health Research Center (CReSA), the Barcelona Supercomputing Center (BSC) and the Generalitat Food Research and Technology Institute (IRTA).

The most important results indicate that the majority of those who have passed COVID-19, regardless of their severity, have protective antibodies for up to a year after infection. But scientists have observed that, Although in the case of hospitalized patients the production of antibodies is higher, 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.

It was the vaccination that caused their antibody levels to increase in all of the individuals in the study, reaching very similar amounts in all.

332 volunteers who suffered from COVID-19 participated in the analysis. 60% of them had it asymptomatic and benign. Meanwhile, the remaining 40% overcame serious illness. All were monitored to neutralize the immune response for 15 months.

Thus, the researchers confirmed that, In most cases, antibody levels are maintained for more than a year, providing protection against COVID-19.

“What we have seen throughout this year is that in the hospitalized patients Protective antibodies reach their maximum level a few days after presenting the first symptoms and, thereafter, decrease markedly, until stabilizing, remaining high over time, ”he explains. Edwards Pradenas, undergraduate researcher at IrsiCaixa and one of the study authors.

“In the case of people who have suffered COVID-19 asymptomatically or mildly, the levels of protective antibodies, although they are also maintained over time, remain lower”, Add.

One of the most remarkable data from the study is that scientists were able to determine that in the case of hospitalized patients, the quality of the antibodies is lower.

The study shows that the protective capacity of antibodies against beta variant, which first appeared in South Africa, it is lost more markedly in hospitalized patients than in people who have passed COVID-19 asymptomatically or mildly.

“Recent data suggests that, in the absence of the vaccine, 50% of study participants could experience re-infection with 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 ”, comments the researcher from IrsiCaixa Julià Blanco.

The administration of the vaccine allowed the antibody levels of the people participating in the study, of different amplitude according to the symptoms, to reach comparable values.

“Although not all of the people we followed received the full immunization schedule, we can say that in all of them their immune response against the virus was enhanced, demonstrating, once again, the obvious benefits of vaccination “, famous Bonaventura Clotet, director of IrsiCaixa.

“The severity of the disease is what determines the extent and effectiveness of the immune response against SARS-CoV-2,” Blanco added.

The expert underlined the importance of analyzing the antibodies: “Having a good immune response is essential, especially now with the appearance of new variants that can compromise the effectiveness of our defenses.

Clotet demonstrated the beneficial effects of vaccination, but considered it necessary to continue to analyze the immune response of those who received doses: “We need to continue to monitor the immunity of the population over the long term so that we can know how long it lasts and whether it is still effective against the new variants. Only in this way will we be able to design optimal prevention strategies to combat the current pandemic ”.

Another recent study on immunity, published by the specialist journal Nature, conducted by a team led by Jackson Turner, Department of Pathology and Immunology, University of Washington School of Medicine, USA, in recovering people with mild SARS-CoV-2 infections, showed that serum anti-SARS-CoV-2 spikeprotein (S) antibody levels decreased rapidly during the first 4 months after infection.

In the initial phase of the study, samples showed this reduction. While between four and eleven months after infection, this reduction slowed down.

However, The researchers also took bone marrow samples from previously infected patients to measure the presence of bone marrow plasma cells., which are important in protecting antibodies and developing long-term protection against the virus.

In the samples, Researchers have found long-lived plasma cells in the bone marrow that are said to produce antibodies against COVID-19. Unlike the decline in other antibodies they observed, BMPC levels were stable for 7 to 11 months after infection. “We are looking for the source of these antibodies which are produced by cells that live in our bone marrow,” said Ali Ellebedy, associate professor at the Washington University School of Medicine in St. Louis, participating in the study. .

The study provides evidence that the immunity induced by SARS-CoV-2 infection is remarkably long-lasting. Besides the good news, “The implications are that the vaccines will have the same effect”says Menno van Zelm, immunologist at Monash University in Melbourne, Australia.

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