A strain of the coronavirus that was first seen in Italy is now the dominant strain of the virus, a group of scientists said Thursday.
In an article published by the peer-reviewed science journal Cell, researchers working with the Sheffield COVID-19 Genomics Group announced that the new strain “has become the most prevalent form in the global pandemic.” The strain is different than what appeared in Wuhan, China, the city where the coronavirus is believed to have originated.
According to the science journal, tracking of the virus frequency revealed a prevalence of the dominant strain, labeled G614, that took over the prevalence of D614, the original strain.
“Dynamic tracking of variant frequencies revealed a recurrent pattern of G614 increase at multiple geographic levels: national, regional and municipal. The shift occurred even in local epidemics where the original D614 form was well established prior to the introduction of the G614 variant,” the scientists wrote in their abstract, referring to the two strains.
“The consistency of this pattern was highly statistically significant, suggesting that the G614 variant may have a fitness advantage,” they continued.
However, scientists cannot agree on the reasoning for the new strain’s dominance — researchers with the study suggested that the newer strain may be more virulent, while others contended in comments included with the study that the dominance could be due to its spread in the U.S.
The United States has largely failed to blunt its surge of new coronavirus infections recently, and now it has more confirmed cases than any other country.
Researchers of the study added that while their findings may indicate that the newer virus strain has a higher transmission rate, there was no evidence yet to suggest that it was a more severe strain than the one thought to have originated late last year in Wuhan.
“In infected individuals G614 is associated with lower RT-PCR cycle thresholds, suggestive of higher upper respiratory tract viral loads, although not with increased disease severity,” they wrote.
The U.S. now has more than 2.7 million confirmed cases of the virus, and on Thursday set another record for new coronavirus cases in a 24-hour period.
Italy, which was hit hard by the virus earlier this year, has largely seen its trend of new cases drop off and now reports under 200 per day across the country.