Related MediaFeb 09, 2021 10:33:37 IST
There is growing evidence that COVID-19 may not protect against re-infection with some of the new variants. People can also get a second infection with earlier versions of the coronavirus if they put up a weak immune system the first time, a new study suggests. The duration of immunity to natural diseases is one of the major issues in the pandemic. Scientists still believe that transplants are very rare and usually as bad as the original ones, but recent developments around the world have raised concerns.
In South Africa, a vaccine study found new infections with variability in two percent of people who had an earlier version of the virus before.
In Brazil, several similar cases were recorded with a new version there. Researchers are investigating whether relapses are helping to explain a recent rise in the city of Manaus, where three-quarters of residents were thought to be infected before.
In the United States, a study found that 10 percent of Marine soldiers who had evidence of prior disease and who re-tested negative before beginning basic training, were re-infected. That work was done before the new variables began to spread, said one study director, Dr. Stuart Sealfon of the Icahn School of Medicine at Mount Sinai in New York.
“A previous infection will not give you a free pass,” he said. “There is a real danger in relapse.”
Feedback is a matter of public health concern, not just a personal matter. Even in cases where reinterpretation does not cause symptoms or just mild ones, people may still spread the virus. That is why health officials are advocating the vaccine as a long-term solution and encouraging people to wear masks, maintain physical speed and wash their hands frequently.
“We are encouraged to do what we have been told to do: get the vaccine out for what we can and do it as soon as we can,” said Dr Anthony Fauci, the government’s chief infectious disease expert. in the US. “I look at the data suggesting … and I want to confirm … the protection afforded by a vaccine is even slightly better” than a natural infection, Fauci said.
Doctors in South Africa began to worry when they saw an increase in cases late last year in areas where blood tests showed many people had already contracted the virus.
Until recently, all indications were “that a previous infection has been protective for at least nine months,” so the second wave should be “substantially controlled,” Dr Shabir Madhi from the University of the Witwatersrand in Johannesburg.
Scientists have discovered a new version of the virus that is more infectious and less susceptible to certain treatments. It now causes more than 90 percent of new cases in South Africa and has spread to 40 countries including the United States.
Madhi led a study testing the Novavax vaccine and found that it was less effective against the new variant. The study also revealed that infections with the new variant were just as common among people with COVID-19 as those without.
“This basically tells us, unfortunately, that a disease in the past with early versions of the virus in South Africa does not protect against the new one,” he said.
In Brazil, a spike in hospitals in Manaus in January caused similar anxiety and revealed a new version that is also more contagious and vulnerable to some treatments.
“Redefining could be one of the drivers of these issues,” said Dr. Ester Sabino of the University of Sao Paulo. She wrote an article in Lancet magazine on a possible explanation. “We have not yet been able to explain how often this happens,” she said.
Scientists from California are also investigating whether a recently identified variant causes reflexes or an increase in cases there.
“We’re looking at that now,” seeking blood samples from past cases, said Jasmine Plummer, a researcher at Cedars-Sinai Medical Center in Los Angeles.
Dr. Howard Bauchner, editor-in-chief of the Journal of the American Medical Association, said he would describe what he described as “the Los Angeles variant.”
New changes did not depend on the reactions seen in the Marines study – it was done before the mutated viruses appeared, said Sealfon, who led that work with the Naval Medical Research Center. Other findings from the study were published in the New England Journal of Medicine; the new ones about redefinition are posted on search website.
The study involved several thousand Marine soldiers who tested negative for the virus three times in a two-week military quarantine under the guidance of basic training.
Among the 189 blood tests that showed they had been infected in the past, 19 tested positive again in the six weeks of training. That’s far less than those without previous infections – “almost half of them contracted the disease at the basic training site,” said Sealfon.
The level and quality of antibodies that Marines had before they arrived was linked to the risk of getting the virus again. No transplants caused serious illness, but that doesn’t mean employers weren’t at risk of spreading disease to others, Sealfon said.
“It seems like a reversal is possible. I don’t think we fully understand why that is and why immunity did not improve ”in these cases, said an immunologist with no involvement in the study, E. John Wherry from University Pennsylvania.
“Natural diseases can leave you with an immune zone,” while vaccines consistently induce high levels of antibodies, Wherry said. “I hope our vaccines do a little better. ”