UK Covid variant rapidly spreading in US and doubling every 10 days, study says

The variant is 35 to 40 per cent more transmissible, researchers say

A highly transmissible variant that was first detected in the United Kingdom has now rapidly spread through the United States and doubles about every 10 days, according to a new study.

The report released on Sunday, which has not been peer reviewed or published in a journal, came from preprint server MedRxiv and it predicted that the UK variant, officially known as B.1.1.7, could become the most dominant Covid-19 variant in the US by next month.

This variant likely entered the country as early as November, according to the group, led by scientists at the Scripps Research Institute in La Jolla, California.

Besides the variant strain doubling every week and a half within the country, researchers also estimated in the report that it was 35 to 40 per cent more transmissible than any other strain that's previously appeared in the US.

Last month, the Centres for Disease Control and Prevention (CDC) model predicted the UK strain could overtake all other strains in the US by March and that it was 50 per cent more transmissible. This latest study has reaffirmed that prediction.

"Our study shows that the US is on a similar trajectory as other countries where B.1.1.7 rapidly became the dominant SARS-CoV-2 variant, requiring immediate and decisive action to minimise Covid-19 morbidity and mortality," researchers wrote in the study's preprint.

Researchers have relied on genome sequencing to identify the different variants across the country, which the US has underperformed in throughout the pandemic.

Florida was mentioned in the study because the state has the highest prevalence of the new variant based on current data, as it's been doubling every 9.1 days and makes up about 4 per cent of cases.

In the US, the variant makes up about 1 to 2 per cent of cases currently, researchers said.

They implored immediate action from the country due to the new variant likely leading to a surge in cases and hospitalisations if it becomes more dominant in the country.

"These findings show that B.1.1.7 will likely become the dominant variant in many US states by March 2021, leading to further surges of Covid-19 in the country," the researchers said.

The CDC has confirmed 611 cases of the variant in 33 states across the country, but the actual number was estimated to be significantly higher.

Cases and hospitalisations have been on the decline across the US after the country experienced a deadly surge due to the winter months and increased holiday travel. But the death toll was still on the rise and increased by 2.4 per cent on a seven-day average, CDC Director Dr Rochelle Walensky said on Monday during the White House Covid briefing.

Experts have warned this new variant could cause another surge, at a time when states have lifted some Covid-19 restrictions for residents.

A mass vaccination campaign was taking place across the country to get as many Americans vaccinated swiftly to prevent any future variants from causing a detrimental toll on the population.

Early research has indicated the UK variant does not impact the efficacy of coronavirus vaccine. Currently Pfizer and Moderna's vaccines have emergency use authorisation by the Food and Drug Administration (FDA) in the US.

But the jabs were less effective against the South African variant, influencing health experts to push for the public to get vaccinated at a higher rate to prevent other mutations from impacting vaccine efficacy .