Deadly Delta Variant Taking Over the World

LONDON — The delta variant is becoming the dominant strain of coronavirus worldwide, according to the WHO, and its combination of high transmissibility, high severity, and escape from vaccines makes it very dangerous, experts told National Geographic.

The variant has a number of mutations in its spike proteins that can make it harder for antibodies to attach to the virus, or easier for it to latch onto and invade human cells. According to science journal Nature, one mutation in particular is at the 'furin cleavage site,' which is important for the virus's ability to replicate inside human airways.

If the virus is better at replicating inside human airways, it can mean an individual is likely to shed more virus particles when infected, a virologist at Imperial College London told the Daily Telegraph.

U.K. Health Secretary Matt Hancock told the BBC this month the variant was around 40 percent more transmissible than the alpha variant. The alpha variant itself is thought to be between 40 and 70 percent more transmissible than the original virus strain found in Wuhan, according to studies cited by the Australian Broadcasting Corporation.

A Public Health England study on vaccine efficacy against the delta variant found the Pfizer-BioNTech vaccine 96 percent effective against hospitalization after two doses, with AstraZeneca 92 percent effective. Overall it found Pfizer-BioNTech 6 percent less effective than it is against the Alpha variant, and AstraZeneca 1 percent less effective.