Analysis from scientists at Houston Methodist in Texas found 28 types of Covid-19 variants in patients in the city, with the origins ranging from Brazil, the UK, California and New York City.
The scientists found 28 cases of the variants, after recently sequencing genomes from around 3,000 patients who had tested positive for Covid-19.
“The numbers of the major variants we have identified in our large sequencing study are disquieting,” Dr James Musser, who led the study, told the Houston Chronicle on Monday.
“The genome data indicate that these important variants are now geographically widely distributed in the Houston metropolitan region,” he added.
Evidence suggests that the Brazil variant may be more contagious than the original strain, but scientists believe that the vaccines available in the US offer protection against them.
Researchers at the University of Texas Medical Branch claimed last month that the Pfizer vaccine, which is one of three available treatments in the US, is less effective against the South African variant than the UK one, but stressed that it is still offers adequate protection.
Dr Wesley Long, a Methodist infectious disease expert who assisted with the Houston study, reiterated that claim, telling the Chronicle that any differences in effectiveness will be minor.
“It doesn’t mean that (current vaccines) are useless,” he told the Chronicle on Monday. “That doesn’t mean that (the new strains) go through walls or defeat masks or that they change the way they are transmitted. All of the rules that we’ve used against Covid still apply,” Dr Long added.
He urged residents to continue practicing coronavirus measures, including social distancing and wearing face masks, to help prevent further spread of the more contagious variants.
Rochelle Walensky, the Director of the Centres for Disease Control and Prevention (CDC), warned on Monday that she is “really worried” about US states rolling back on similar coronavirus measures amid the new variants being recorded across the country.
“Please hear me clearly: at this level of cases, with variants spreading, we stand to completely lose the hard-earned ground we have gained,” Dr Walensky said. “These variants are a very real threat to our people and our progress,” she added.
Dr Walensky urged US residents to continue with Covid-19 measures, adding: “We have the ability to stop a potential fourth surge of cases in this country. Please stay strong in your conviction.”
Over the weekend, the US Food and Drug Administration (FDA) approved a one-dose vaccine from Johnson & Johnson, with more than 4 million doses already shipped to states across the US.
The country has also vaccinated more than 50 million people, with that figure expected to rise rapidly with three vaccines now being administered.
Since the start of the pandemic, Texas has recorded more than 2.66 million coronavirus cases and at least 44,078 deaths, as it has been one of the worst affected states in the US.
According to Johns Hopkins University, there are now more than 28.6 million people who have tested positive for the coronavirus in the US. The death toll has reached 514,660.