Virus Variant in Brazil Infected Many Who Had Already Recovered from Covid-19

In just a few weeks, the two variants of coronovirus have become so familiar that you can regularly hear their irreversible alphanumeric names spoke On television news.

First recognized in the UK, B.1.1.7 has demonstrated the power to spread far and fast. In South Africa, a mutant called B.1.351 can dodge human antibodies, blunting the effectiveness of some vaccines.

Scientists have tracked about a third of the version originating in Brazil, called P.1. Research on P.1 had slowed since its discovery in late December, leaving scientists unable to find out how much to worry about.

“I held my breath,” said Broadwyn epidemiologist Bronwyn McInnis.

Now three studies in the Amazon city of Manaus, p. 1 provide a daring history of meteorite growth. It probably originated there in November and then fueled a record-breaking spike in coronovirus cases. Research has found that it has come to dominate the city due to the increased infectious disease. But it also gained the ability to infect some people who had immunity from Kovid-19’s previous encounters. And laboratory experiments suggest that P.1 may weaken the protective effect of the Chinese vaccine now in use in Brazil.

The new studies have not yet been published in scientific journals. Their authors warn that findings on cells in laboratories do not always translate to the real world, and they are only beginning to understand the behavior of P.1.

“The findings apply to Manaus, but I don’t know if they apply to other places,” said Nuno Faria, a virologist at Imperial College London, who helped lead the new research.

But even with the mysteries that live around P.1, experts said this is a type to be taken seriously. William Hainz, an epidemiologist at the Harvard TH School of Public Health, said “it is right to be concerned about P1 and this data gives us the reason for it”.

P.1 is now spreading to the rest of Brazil and found in 24 other countries. In the United States, the Centers for Disease Control and Prevention has reported six cases in five states: Alaska, Florida, Maryland, Minnesota, and Oklahoma.

P. To reduce the risk of outbreaks and prevalence of 1, Drs. Faria said it was important to double every measure to slow the spread of coronovirus. Masks and social distances may work against P.1. And vaccination can help reduce its transmission and protect those infected with critical illness.

“The final message is that you need to complete all vaccination efforts as soon as possible,” he said. “You need to be one step ahead of the virus.”

Dr. Faria and his colleagues started tracking coronoviruses when it exploded in Brazil last spring. Manaus was a city of 2 million in the Brazilian Amazon Hit particularly hard. At the peak of its spring, the tombs of Manaus were overwhelmed by the corpses of the dead.

But after a peak in late April, Manaus had the worst past of the epidemic. Some scientists thought the drop meant Manaus herd immunity.

Dr. Faria and his colleagues looked for coronovirus antibodies in samples from a Manaus blood bank in June and October. They determined About three-quarters Manaus residents were infected.

But near the end of 2020, New cases start growing again. Dr. “There were actually far more cases at the end of April than in previous cases,” said Faria. Faria said. “And it was very surprising for us.”

For the discovery of variants, Drs. Faria and his colleagues launched a new genome sequencing effort in the city. While B.1.1.7 arrived in other parts of Brazil, they were not found in Manaus. Instead, he found a version that no one had seen before.

Several variants in their samples shared a set of 21 mutations, which were not seen in other viruses circulating in Brazil. Dr. Faria sent a text message to a co-worker: “I think I’m seeing something really strange, and I’m quite worried about it.”

Some mutations particularly worried him, as scientists had already found him in B.1.1.7 or B.1.351. Experiments suggested that some mutations may be better able to infect cells. Other mutations allow them to avoid antibodies from previous infections or to be produced by vaccines.

As Dr. Faria and his colleagues analyzed their results, were researchers in Japan Do a similar search. On January 4, four tourists returning home from a trip to Amazon tested positive for coronavirus. Genome sequencing revealed the same set of mutations that Drs. Faria and his colleagues were watching in Brazil.

Dr. Faria and his colleagues Posted P.1 details On January 12 at an online virology forum. He then investigated why P.1 was so normal. Its mutation has made it more contagious, or it may be lucky. By sheer coincidence, the variant may have shown in Manaus that the city was more relaxed about public health measures.

It was also possible that P.1 became common because it could affect people. Generally, coronovirus infections are rare, as antibodies produced by the body are potent for months after infection. But it was possible that P.1 carried out the mutation that made it difficult for those antibodies to latch onto it, causing it to slip into cells and cause new infections.

Researchers tested these possibilities by tracking P.1 from their initial samples in December. In early January, it made up 87 percent of the sample. By February it had fully taken over.

Combining data from the genome, antibodies and medical records in Manaus, the researchers concluded that P.1 thanked the city not for luck but for biology: its mutation helped it spread. Like B.1.1.7, it can infect more people than other variants. They estimate that it is 1.4 and 2.2 times more permeable than other lineages of coronavir.

But it also gains from mutations that allow it to avoid antibodies to other coronaviruses. He estimates that between 25 and 61 of the 100 people who were infected in Manaus last year may be re-infected with P1.

Researchers found support for this conclusion an experiment In which he mixed the P.1 virus with antibodies to Brazilians who had Kovid-19 last year. They found that the effectiveness of their antibodies decreased six times against P1 compared with other coronavir. That drop may mean that at least some people are vulnerable to new infections from P1.

Dr. Faria said, “There appears to be a growing body of evidence suggesting that most cases involving the second wave are in fact somewhat halter.”

Dr. Faria and other researchers are now looking across Brazil to observe the spread of P.1. An infectious disease specialist of the University of São Paulo School of Medicine, Drs. Esther Sabino said that an outbreak occurred in the Brazilian city of 223,000 people, which did not have a high rate of Cidid-19 before P.1 arrived. .

If before the advent of P.1, people in Araraquera did not have a high level of antibodies, he said, this suggests that the variant might be able to spread to locations without an extreme history of Manaus. “It can happen at any other place,” he said.

Michael Verobe, a virologist at the University of Arizona who was not involved in the research, said it was time to focus on P1 in the United States. He expected it to become more common in the US, although it would have to compete with B.1.1.7, which could soon become the dominant version in most parts of the country.

“At the very least, it’s going to be one of the contenders,” Dr. Vorobe said.

Dr. Faria and his colleagues, in their experiments, tested antibodies of eight people received Coronavac, A Chinese-made vaccine that has been used in Brazil. They found that vaccine-borne antibodies were less effective at inhibiting the P.1 variant than other variants.

Dr. Faria cautioned that these results from cells in the test tube, not necessarily vaccines, would be less effective at protecting real people from P1. Vaccines may very well provide strong protection from P.1, even though the antibodies they produce are not very potent. And even if the variant manages to infect those vaccinated, they will likely survive a severe bout of Kovid-19.

Dr. For Sabino, the ultimate importance of P.1 is the danger that they can pop up anywhere in the world, regarding variants.

“It’s just a matter of time and chance,” she said.

Source link

Leave a Comment