Only one sub-lineage of the delta variant of COVID-19, which was first detected in India, is still considered a “concern”, while two others have been demoted, the World Health Organization (WHO).
The B.1.617 variant, renamed Delta, and believed to be partially responsible for the outbreak in India, has since spread to more than 50 regions, with three distinct sublines.
The World Health Organization classified the entire variant as “of concern” last month, but said on Tuesday that only one sub-line should be considered as such.
“It has become clear that more risks to the public are associated with B.1.617.2, while lower rates of transmission have been observed with other subspecies,” WHO said in its weekly epidemiological update on the epidemic.
B.1.617.2 remains a concern that, along with three other types of virus, is considered more dangerous than the original because it is more contagious or deadly, or because vaccines may not provide protection against it.
The World Health Organization on Monday assigned the Greek letters to the scientific names of various variants such as Alpha, Beta, Gamma or Delta for the case of B.1.617. In particular, this initiative aims to avoid “stigmatization and discrimination” of the names of the countries and territories in which they appear.
“We continue to see a significant increase in transmissibility and an increasing number of countries are reporting outbreaks associated with this variant,” notes the World Health Organization, which is a “priority” for conducting “new studies” on its impact.
The new hybrid variant, which was reported Saturday by health authorities in Vietnam, appears to be a different type of Delta, Dr. Maria Van Kerkhove, technical director of COVID-19 control at the agency, said on Tuesday.
“We know that B.1.617.2, from the delta variant, has increased transmissibility, which means it can spread more easily between people,” she said.
On the other hand, the subline B.1.617.1 was demoted to the category of “variable of interest” and named Kappa.
For B.1.617.3 it is no longer considered interesting by the WHO and no Greek letter is assigned due to its relatively low incidence.