The highly infectious variant B.1.1.7 of coronavirus, which was first observed in Kent, had spread to the United States by November 6, according to a new study.
The strain is up to 70 percent more contagious and appeared in a chronically ill patient on September 20.
It was announced to the British public only in mid-December, when it was identified as a source of jump in cases and called a “variant of concern”.
Researchers at the University of Arizona are studying the genomes of 50 B.1.1.7 infections in the United States and tracking their genus to determine when the mutated variant first appeared in the United States.
They found two clusters of infections, one in California and one in Florida, that occurred on November 6 and November 23, respectively ̵
This retrospective study has the advantage of genomic analysis and retrospective, and the first actual case of the Kent strain was not diagnosed in an American until December 29.
“Surprisingly, this genus may have already been established in the United States in about 5-6 weeks before B.1.1.7 was first identified as a variant of concern in the United Kingdom in mid-December,” the researchers wrote.
“And it may have circulated in the United States nearly two months before it was first opened on December 29, 2020.”
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Newer variants of the coronavirus have mutations in the thorn protein that are key to the antibodies of the immune system to attach and destroy it. Changing their shape makes it difficult for the body to catch the virus
The study has not yet been reviewed, but is available online as a prepress.
The exact origin of the Kent variant is unknown, but it is thought to have originated in mid-September.
Dr Susan Hopkins, a senior public health official in England (PHE), said in December that at first “there was nothing to emphasize that this was a matter of serious concern as options came and went”.
Mutations in viruses occur all the time, and most of them are harmless or harmful to the pathogen.
Coincidentally, however, tweaks to the virus code sometimes give it a survival advantage and increase its success, often becoming more contagious and easier to spread.
This is thought to have occurred in variant B.1.1.7, which previous studies found to be richer in the upper respiratory tract.
The mutation in the thorn protein – which emerges from the coronavirus and hijacks human cells – has made it better for infecting humans.
This so-called N501Y mutation is also found in the South African and Brazilian variants, which have since been identified.
Arizona-based researchers found that all cases in California share another small mutation, which occurs in only 1.2% of European cases B.1.1.7.
This, they say, shows an introductory event, probably from an international trip that sowed the variant in California, where it then spread from person to person.
A similar trend is observed in Florida batches of cases that are very similar to the most common type B.1.1.7 observed in the United Kingdom.
This is a “strong indication that they also come from an introduction,” scientists say.
At least three major variants of the coronavirus have been spotted in the UK in recent months – from Kent, South Africa and Brazil – and they appear to be evolving to spread faster and avoid certain parts of the immune system, although scientists are still still don’t think it has yet gotten to the point of completely slipping past the vaccines
When the UK government revealed that the option was likely to cause a jump in local cases in the UK in mid-December, it plunged the South East, London and East of England into Level 3 restrictions.
UK government scientific advisers say it is up to 70 per cent more contagious than the previous dominant option and encourage people to stay home to prevent transmission.
It is now estimated to account for more than 60% of all cases in the UK, but in California, between December 27 and January 2, only 0.4% of cases were with the Kent variant. In a comparable period in the United Kingdom, this figure was 1.2%.
“This suggests that the dynamics of B.1.1.7 may be slightly more explosive in California than the original epicenter in England,” the researchers said.
“Treasure 2 in Florida (population 21 million), on the other hand, has shown a faster displacement of non-B.1.1.7.”
Here, this represents 0.7% of cases 34 days after its first appearance in the state and “compared to the outbreak of B.1.1.7 in England, B.1.1.7 represents about 0.1% of all cases”.
“Therefore, although it is clearly younger than the California genus of Firewood 1, the Florida genus of Firewood 2 already accounts for a larger share of the Florida SARS-CoV-2 epidemic than the California SARS-CoV outbreak. -2. “
At present, link B.1.1.7 represents only 0.3% of coronavirus infections in the United States, the researchers said.
The reason for the different rate at which B.1.1.7 overtakes pre-existing spots remains unknown, but researchers provide several options in their study.
“One possibility is that the transmission advantage of B.1.1.7 may vary depending on the intensity of the mitigation,” they say.
“Perhaps this line of SARS-CoV-2, with apparently higher viral loads in the upper respiratory tract than other variants, is able to generate super-scattering events with relative ease when mitigation efforts are relatively weak, but the advantage the transmission is less sharp when playing the field is leveled for example with the extensive use of masks and avoidance of the indoor crowd.
“Another possibility is that non-B.1.1.7 lines circulating in the United States, especially in California, may be more transmittable than non-B.1.1.7 lines in England, with which B.1.1.7 competes. , giving B.1.1.7 less than a transmission advantage and, therefore, a slower rate of offset of non-B.1.1.7 lines. “
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