The Delta variant of the novel coronavirus, also known as B.1.617.2, has been designated as a “variant of concern” by the US Centers for Disease Control and Prevention.
The designation of “variant of concern” is given to virus strains that scientists believe are more transmissible or capable of causing more severe disease. Detection vaccines, treatments, and tests may be less effective against a variant of concern. The Delta variant had previously been considered a variant of interest by the CDC.
The Delta variant, which was first discovered in India, has increased transmissibility, a potential reduction in neutralization by some monoclonal antibody treatments under emergency authorization, and a potential reduction in neutralization from sera after vaccination in laboratory tests, according to the CDC.
On May 10, the World Health Organization designated the Delta variant as a variant of concern.
In the United States, Covid-19 cases have been declining in recent months, but there is concern that this may change as vaccination rates slow and the Delta variant spreads. As of June 5, the CDC estimates that it was responsible for 9.9% of all cases in the United States.
Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, encouraged everyone to get vaccinated against Covid-19 at a White House Covid-19 briefing last week, noting that the Delta variant was in circulation in the United States at a rate similar to the tipping point seen in the UK, where the variant is now dominant.
“We cannot allow that to happen in the United States,” Fauci said, describing the UK’s experience as a “powerful argument” for vaccination.
The variant is thought to be to blame for the recent spike in cases in the UK, and a study of cases in Scotland published on Monday found that it was linked to nearly double the risk of hospitalization when compared to the Alpha variant, B.1.1.7, which was first discovered in the country.
Following an increase in cases and, in particular, the growing spread of the Delta variant, the UK announced Monday that the easing of coronavirus restrictions would be postponed for another four weeks, until July 19.
According to Dr. Eric Topol, the founder and director of the Scripps Research Translational Institute, whose outbreak.info has been tracking variants throughout the pandemic, the Delta variant was responsible for about 10.3 percent of US Covid-19 cases as of Sunday.
Although it may not appear to be a large number, the rate at which it is spreading is alarming.
“It doubles every seven to ten days,” Topol explained, “which means this variant will be dominant in three weeks.” “That means we only have two to three weeks to stop this trend by going all out with vaccination.”