Cases of a new, more transmissible coronavirus strain that was first detected in the UK were reported last week in California, Colorado, Florida, Georgia and New York.
San Diego County confirmed 24 new cases involving the variant on Tuesday. In total, the five states reported more than 30 cases. But, in all likelihood, the variant entered the United States long before these infections were detected and has been spreading silently for weeks.
None of the infected people have recently traveled outside the United States. Charles Chiu, an infectious disease specialist at the University of California, San Francisco, told Business Insider that he is “worrying because it suggests that the virus is circulating in our community now”.
In fact, the Centers for Disease Control and Prevention confirmed last week that the variant was “passed from person to person in the United States”.
Chiu believes the variant was introduced in the United States in early December or shortly thereafter.
“It is very likely to be in every state,” he said.
The variant is not responsible for most cases in the USA
More than 30 countries have reported cases of the mutated strain, which was first detected in Kent and London on 20 and 21 September. In mid-November, the strain – which geneticists called B.1.1.7 – accounted for 28% of cases in London. Three weeks later, that number jumped to 62%.
England’s M56 motorway on December 21.
PAUL ELLIS / AFP via Getty Images
According to Lucy van Dorp, a researcher at the Institute of Genetics at University College London, the variant probably crossed the Atlantic after reaching high frequencies in the UK – probably in late autumn.
If the variant follows the same trend in the United States and the United Kingdom, she said, it could take a few months to “reach striking frequencies”.
However, public health officials in Los Angeles are already looking for the variant among the county’s virus samples. Hospitalizations and coronavirus cases have reached unprecedented levels in LA County: their total infection count doubled from 400,000 to 800,000 in the last month and the average number of new hospitalizations per day jumped from 790 in early November to about 7,600 in January 2nd.
No cases involving the variant have yet been found in LA County – all California cases are in San Bernardino and San Diego counties. But Mayor Eric Garcetti told the LA Times that he suspects the new variant is a factor in the recent increase in cases.
“It happened devastatingly and quickly. Everyone I talked to said that this acceleration was beyond any model and any expectation, so people say, ‘What broke?’ and I have to think that it is partly the tension that existed, “said Garcetti on Wednesday.
Nurse Michelle Goldson in the ICU at Martin Luther King Jr. Community Hospital on December 17 in Los Angeles.
Francine Orr / Los Angeles Times via Getty Images
However, based on genetic data collected in the United States to date, Chiu said the strain is unlikely to have contributed significantly to the increase in cases.
“It does not appear that this strain is prevalent, at least not currently,” he said, adding, “I think the evidence so far suggests that we are seeing this in less than 1% of cases. But if this strain is in fact more transmissible, we can start to see an increasing proportion of infections by this strain. “
The more we search, the more we will find
Countless versions of the coronavirus are circulating around the world, each separated by a handful of small changes in its genome. To maintain control over these strains, researchers genetically sequence samples of the virus and monitor changes over time.
But the United States genetically sequences less than 0.01% of coronavirus cases: only 2.5 out of 1,000. In the UK, by comparison, laboratories are sequencing 45 out of 1,000 cases. That is probably the reason why the US missed the introduction of the new variety.
“We did relatively little genomic surveillance in the US compared to the UK. For example, in Connecticut, we sequenced about 0.3% of cases. In the UK, the target is 10% of cases,” Nathan Grubaugh, an epidemiologist at Yale School of Medicine, told Business Insider.
“So the mutation could be more widespread and we just don’t know,” he added, also noting that the variant was probably introduced in the United States several times.
Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, during a meeting of the Coronavirus Task Force at the White House on November 19.
Tasos Katopodis / Getty Images
Many public health officials assumed the variant was in the United States many days before cases were found.
“Given the small fraction of infections in the U.S. that have been sequenced, the variant could already be in the United States undetected,” said the CDC on December 22, a week before Colorado officials reported the first case.
Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said on December 21 that the strain was almost certainly already in the United States.
“When we start looking, we will find,” Fauci told PBS NewsHour.
The more researchers sequence patients’ samples, the better they will be able to detect new strains early, said van Dorp.
“There may be other similar variants elsewhere that have not been detected in other regions of the world due to less intensive sequencing efforts,” she said.
The new variant can be 56% more contagious
A deserted road in front of the Royal Opera House in Covent Garden, London, on December 19th.
Keith Mayhew / SOPA Images / LightRocket via Getty Images
Coronavirus usually accumulates two mutations per month, most of which do not affect its infectivity or mortality.
But in the case of B.1.1.7, the virus collected at least 17 mutations at a time. Some of these mutations affect the virus’s spike protein, which it uses to invade cells. This could make it easier to infect people.
New research suggests that the strain is about 56% more contagious than the original virus that emerged in China. The variant has outpaced all other versions of the virus in the UK since late November. In mid-December, six out of 10 new cases of coronavirus in the UK were the new variant.
Given the spread and the frequency with which people travel between the United States and the United Kingdom, “the arrival of this variant in the United States was expected,” according to the CDC. (There are 16 flights a day from London Heathrow Airport to New York JFK Airport.)
At least 27 countries banned travel from the UK last month; the US does not. But travel bans are generally not enough to stem the spread of a virus, according to Grubaugh, because the restrictions are not airtight – essential travel continues. The bans came too late: by mid-December, the virus had already been detected in at least eight countries.
“If a country is concerned about introducing a new variant and increasing local transmission, a more effective plan is to implement measures to decrease local transmission,” said Grubaugh.
Strict adherence to social distance and the use of masks “will stop the virus, variant or not,” he added.
This story has been updated with new information on cases in California and Georgia. It was originally published on January 5 at 8:04 am
Susie Neilson contributed reporting.