Most covid patients remain immunized for almost two years

A nurse treats a patient infected by covid-19. / EFE

The mere infection, in the absence of vaccines, generates “robust and lasting” antibodies with only 3% of reinfections by the virus, according to research by Spanish scientists

The antibodies that SARS-CoV-2 infection naturally generates in those who fall ill with this coronavirus are “powerful” and “long-lasting”. These defensive biological agents illuminated by the organism attacked by the covid guarantee by themselves in most of the patients investigated an immunity that lasts for almost two years. This is the conclusion of an investigation carried out by Spanish scientists in the first year and a half of the pandemic, published in the specialized journal ‘BMC Medicine’.

The results of this research are important in themselves, since they reveal very relevant data on the response of the human body to the attack of SARS-CoV-2, but they are especially important for the design of health strategies and policies in many poor and poor countries. Few developed.

In Europe, since the immunization of the population against covid with successive doses of the vaccine became widespread at the end of 2021, the effect of natural antibodies has been losing some importance, but we forget that even today 35% of the The world’s population has not even received a single shot from the anti-coronavirus serums. that they have no defense against the pandemic other than that provided by their own immune system. Knowing the immune response after infection and its effectiveness “are key elements to guide decisions on how to control this and future coronavirus pandemics,” say the signatories of the article.

The research is a joint effort by the Barcelona Institute for Global Health (ISGlobal), the Catalan Health Institute, the Jordi Gol University Institute for Primary Care Research and the Daniel Bravo Andreu Foundation.

The study consisted of the systematic control of the quantity and effectiveness of the five main antibodies generated by our body against the coronavirus in a large group of health workers from populations in the center of Catalonia who had contracted covid. There are 247 people, who had developed an infection with symptoms by SARS-CoV-2, and from whom samples were taken for analysis at up to eight different times between the summer of 2020, with the end of the first wave, and November 2021 These are patients of all ages who had not received the vaccine during the control period.

The first, predictable conclusion says that the number and defensive power of the antibodies decreases clearly and gradually over the months since the infection. However, more than 90% of the participants had the presence of the five main antigens during the 20 months analyzed. Moreover, in the 23 participants who had not yet been vaccinated in November 2021 “seropositivity remained at 95%”.

Eight reinfections out of 247

The defensive efficacy against SARS-CoV-2 of those infected was very high and caused “robust and long-lasting immunity”, even against successive variants, such as those that arrived from Great Britain and South Africa (alpha and delta). Proof of this immunological reliability is that only in 8 of the 247 investigated, in 3.2% of the group, the natural antibodies were unable to stop reinfection.

The data collected in the fall of 2021, the last weeks of the investigation, when they were already participating were already on the verge of being vaccinated, offer two other very relevant data. Belonging to older age groups and being a regular smoker correspond to lower antibody levels over the months. Factors that help the opposite were also detected. Having been hospitalized and presenting symptoms such as fever or loss of taste of smell, both signs that reveal a more powerful infection, generate more antibodies and a more lasting effectiveness.

In conclusion, the researchers say, “maintaining detectable levels of antibodies confers protection against reinfection even in the absence of vaccination.” However, they clarify, “it must be remembered that this study was carried out before the arrival of omicron, and that infected people also benefit from vaccination, since hybrid immunity – natural response plus response to the vaccine – is what best protects against infection and disease.