A variant of COVID-19 raises concerns that people may be infected again

Evidence is increasing COVID-19 It may not be possible to prevent reinfection with some new variants. New studies suggest that people can also get a second infection with an earlier version of the coronavirus if they first implement a weak defense.

The duration of immunity from natural infections is one of the major problems with pandemics. Scientists still consider reinfections to be fairly rare and usually less serious than the first infection, but recent developments around the world have raised concerns.

To South AfricaIn a vaccine study, a new infection with a variant was found in 2% of people who had previously had an earlier version of the virus.

In Brazil, several similar cases have been documented in the new variant. Researchers are investigating whether reinfection can help explain the recent surge in the city of Manaus, where three-quarters of the population was previously thought to be infected.

In the United States, one study found that 10% of Marines who had previously been infected and were repeatedly negative before the start. Basic training I was infected again later. The work was done before the new variant began to spread, said one research leader, Dr. Stuart Sirphon of Mount Sinai School of Medicine in New York.

“Previous infections don’t give you a free pass,” he said. “There remains a considerable risk of reinfection.”

Reinfection causes public health problems as well as personal problems. The virus can spread even if the reinfection causes no symptoms or is mild. Therefore, health officials encourage vaccination as a long-term solution and encourage people to wear masks, keep physical distance and wash their hands frequently.

“It’s an incentive to do what we’ve been saying. Immunize as many people as possible and immunize as soon as possible,” said Anthony, the U.S. government’s premier infectious disease expert. Dr. Fauci said.

“Looking at the data … and I want to emphasize … the vaccine-induced defenses may be a little better than natural infections,” Forch said.

Ph.D. at CBS’s “Face the Nation” on Sunday. Scott ottliebA former member of the US Food and Drug Administration on the board of directors of vaccine developer Pfizer, he said the vaccine would probably be less effective against South African and Brazilian variants, but he said the vaccine was against the variants. I thought it would provide “reasonable protection”.

“We may also be able to develop a consensus strain that burns in various variations in a timely manner, perhaps in 4-6 months, with boosters available in the fall. This mutating virus There is a good chance that we can stay ahead of the curve. “

South African doctors began to worry when they saw a surge in cases late last year in areas where blood tests suggested that many were already infected with the virus.

Until recently, the second wave should have been “relatively suppressed,” as all the signs were “previous infections provide protection for at least nine months,” said Dr. Shabir Madhi of the University of the Witwatersland in Johannesburg. Said.

Scientists have discovered a new version of the virus that is more contagious and less susceptible to specific treatments.Currently, it causes more than 90% of new cases in South Africa and has spread to 40 countries. Including the United States..

Maddy led a study testing the Novabax vaccine and found it to be less effective against new variants. The study also found that infection with new mutants is just as common between those who have COVID-19 and those who do not.

“Unfortunately, this basically tells us that past infections with early variants of the virus in South Africa are not protected against new ones,” he said.

In Brazil, a surge in hospitalizations in Manaus in January caused similar concerns, revealing new variants that are more contagious and less vulnerable to some treatments.

“Reinfection may be one of the driving forces in these cases,” said Dr. Ester Sabino of the University of São Paulo. She wrote an article in the journal Lancet for possible explanations. “We haven’t yet defined how often this is happening,” she said.

Scientists in California are also investigating whether recently identified variants are causing reinfection and whether cases are proliferating there.

“We are considering it now,” said Jasmine Plummer, a researcher at the Cedars-Sinai Medical Center in Los Angeles.

Dr. Howard Bauchner, Editor-in-Chief of the Journal of the American Medical Association, said he would soon report on what he called a “variant in Los Angeles.”

The cause of the reinfection seen in the Marine Corps study was not a new variant — it took place before the emergence of the mutated virus, said Sealfon, who led the study at the Naval Medical Research Center. Other findings from this study were published in the New England Journal of Medicine. New information on reinfection can be found on the research website.

The study involved thousands of Marines who were three times negative for the virus during two weeks of supervised military quarantine before starting basic training.

Of the 189 people who were previously shown to be infected by blood tests, 19 were again positive during the 6-week training. This is far less than previously uninfected people — “almost half of them were infected at the basic training site,” Sealfon said.

The quantity and quality of antibodies that previously infected Marines had upon arrival was associated with the risk of re-infection with the virus. Reinfection did not cause serious illness, but that does not mean that recruits were not at risk of spreading the infection to others, Sealfon said.

“It looks like reinfection is possible. I don’t think we fully understand why and why immunity is underdeveloped,” said E., an immunology expert who was not involved in the study. .. John Welly University Pennsylvania.

According to Welly, vaccines consistently induce high levels of antibodies, while “natural infections can leave a variety of immunity.”

“I’m optimistic that our vaccine is a little better.”