Antibodies that are produced by a person’s immune system to fight off mild cases of COVID-19 may not persist for too long, if a new study published in the New England Journal of Medicine is anything to go by. Less severe patients of the new coronavirus infection may not be protected against future development of symptoms if they are reinfected by the SARS-CoV-2 virus.
There has been growing debate over reinfection in people who have already recovered from COVID-19 once, as the scientific community is still divided over the subject of long-term immunity against the disease. Even the concept of herd immunity is being hotly debated, with different estimations over how a population could become fully immune to COVID-19 in the future.
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For the study, scientists had taken antibody samples from 34 people who had recovered from COVID-19. All these people were exposed to mild levels of infection and no one had to be admitted to intensive care. The patients were able to fight off the infection and stage a recovery with the help of supplemental oxygen and HIV drugs. None of the patients were put on a ventilator, nor were they given the Ebola drug Remdesivir.
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The researchers analysed these patients for the first time after taking antibody samples from them 37 days after they were infected. The second analysis was performed 86 days later (less than three months). In that time, the scientists found that after recovering from COVID-19, the antibody levels of these patients fell rapidly. It was reported that the antibodies had been halved in 73 days. According to study, the antibodies developed against COVID-19 fell faster than the antibodies to the SARS disease, which came out of another coronavirus named SARS-CoV in the year 2002-03.
Scientists the world over are investigating, analysing and researching various aspects related to COVID-19, including how long immunity persists in patients' bodies after recovering from this disease. A previous research stated that antibodies developed in COVID-19 patients may persist between 3 and 6 months. But the latest study says that the immunity developed against COVID-19 naturally may die out sooner than previously thought.
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However, there haven’t been many instances of reinfection of COVID-19 and there isn’t enough evidence available either. The latest study also states that although the role of antibodies in protecting against infection is not fully understood, they usually represent little protection against the infection. The research's principal scientist, F Javier Ibrondo, has also called for further studies to be done to find out to what extent COVID-19 antibodies live on in the body and by how much they drop after 90 days.