A more contagious variant of the coronavirus first found in Britain is spreading rapidly in the United States and doubling approximately every ten days, according to a new study.
By analyzing half a million coronavirus tests and hundreds of genomes, a team of researchers predicted that this variant could become dominant in the United States in a month, potentially causing a resurgence of new cases and an increased risk of death. .
The new research provides the first nationwide look at the history of the variant, known as B.1.1.7, since it arrived in the United States in late 2020. Last month, the Centers for Disease Control and Prevention warned that B.1.1. 7 could be predominant by March if it behaves in Britain as it does. The new study confirms the projected path.
“Nothing in this article is surprising, but people should see it,” says Kristian Andersen, co-author of the study and a virologist at the Scripps Research Institute in La Jolla, California. ‘We probably need to prepare for it by March in most places in the United States predominantly. ”
Dr. Andersen’s team estimated that the transmission rate of B.1.1.7 in the United States is 30 to 40 percent higher than that of more common variants, although the numbers may increase as more data comes in, he said. The variant has already been implicated in trainings in other countries, including Ireland, Portugal and Jordan.
“Indeed, a very serious situation can develop within a few months or weeks,” said Nicholas Davies, an epidemiologist at the London School of Hygiene and Tropical Medicine, who was not involved in the study. “These may be early signals that warrant urgent investigation by public health authorities.”
Dr. Davies warned that US data is fuller than those in Britain and other countries with national monitoring systems. Nevertheless, he found results from some parts of the United States particularly worrying. In Florida, where the new study indicates that the variant is spreading particularly fast, Dr. Davies that a new boom could hit even faster than the rest of the country.
“If this data is representative, there may be limited time to act,” he said.
Dr. Andersen and his colleagues posted their study online on Sunday. It has not yet been published in a scientific journal.
When the British government announced the discovery of B.1.1.7 on 20 December, dr. Andersen and other researchers in the United States began investigating it in U.S. coronavirus samples. The first case took place on December 29 in Colorado, and dr. Andersen found himself in San Diego shortly thereafter. In short order, it has been noticed in many other parts of the country.
But it was difficult to determine how wide the variant was. B.1.1.7 contains a characteristic set of 23 mutations distributed in a genome of 30,000 genetic letters. The best way to find out if a virus belongs to the B.1.1.7 lineage is to sequence the entire genome – a process that can only be performed with special machines.
The CDC has entered into a contract with Helix, a laboratory testing company, to examine their Covid-19 samples for signs of B.1.1.7. The variant can give a negative result on one of the three tests that Helix uses to detect the coronavirus. For further analysis, Helix sent these suspicious samples to Illumina to have their genomes sequenced. Helix contacted dr. Andersen and his colleagues to help analyze the data.
Analyzing 212 U.S. B.1.1.7 genomes, Dr. Andersen’s team concludes that the variant probably only arrived in the United States in late November, a month before it was detected.
The variant has been introduced in the country at least eight times separately, probably due to people traveling to Britain between Thanksgiving and Christmas.
The researchers combined data from the genome sequence with Helix’s overall test results to make an estimate of how fast the variant spread. It has become exponentially more common over the past two months.
In Florida, scientists estimate that more than 4 percent of cases are now caused by B.1.1.7. According to the team’s calculations, the national figure could be 1 percent or 2 percent.
If this is true, a thousand or more people can become infected with the variant every day. The CDC recorded only 611 B.1.1.7 cases, which testifies to the inadequacy of the country’s genomic surveillance.
In parts of the country where Helix does not test much, it will probably underestimate the spread, warns dr. Andersen.
“It’s clearly not enough,” he said. “I can guarantee you that there are places where B.1.1.7 would be relatively common, now that we are not going to pick it up.”
Nathan Grubaugh, a virologist at Yale University who was not involved in the new study, says the data makes it clear that the incidence of B.1.1.7 is increasing just as scientists have warned. But he does not think the new study explains exactly how it grows. “It does not reveal the cause at this stage,” he said.
It is possible that chains of B.1.1.7 transmission spread faster than other viruses. Or it could be that B.1.1.7 was more common among incoming travelers starting new outbreaks.
“I still think we do not even know how it will turn out,” said Dr. Grubaugh said.
The contagion of B.1.1.7 makes it a threat to be taken seriously. Public health measures working on other variants may not be enough to stop B.1.1.7. More cases in the United States will mean more hospitalizations, which could hamper hospitals that are only now recovering a record number of patients last month.
To make matters worse, Dr Davies and his colleagues at the London School of Hygiene and Tropical Medicine on Wednesday posted a study online indicating that the risk of dying B.1.1.7 is 35 per cent higher than for other variants. The study has yet to be published in a scientific journal.
Communities can take steps to combat variants such as B.1.1.7, such as dr. Grubaugh and his colleagues from Yale University recently described in Cell magazine. They said, for example, that health officials should reinforce messages about wearing effective masks, avoid large gatherings, and ensure that indoor spaces are well ventilated.
The scientists also urged governments to require sick leave for people diagnosed with Covid-19 to stop the spread of the workplace. “Such measures can help significantly reduce community transfer,” said Dr. Grubaugh and his co-authors wrote.
Vaccinations can also be part of the strategy to fight B.1.1.7. In Israel, where the variant is now predominant, new cases, serious illnesses and hospitalizations have already dropped significantly in people over 65, a group that has given the highest priority to vaccines.
“What we need to do with the current vaccines is to get it into as many people as possible as quickly as possible,” said Dr. Andersen said.
Driving B.1.1.7 also reduces the risk that the variant will develop into something worse. Already in Britain, researchers found samples of B.1.1.7 that received a new mutation with the potential to make vaccines less effective. It is not clear whether these viruses will be common. But they demonstrate that the coronavirus still has a lot of evolutionary space to explore.
“We have to expect them to show up here,” said Dr. Andersen said. “Whatever was true elsewhere will also be true here, and we must deal with it.”