Back in 2021, just as the long-awaited vaccine against COVID-19 rolled out, so did a new variant of the virus: Delta. Scientists say that out of all the five known variants of concern, which have been shown to evade therapeutic antibodies and vaccines, Delta is the most virulent leading to severe symptoms and increased mortality among infected people.
While experts agree that the vaccines still offer strong protection against infection by the Delta variant, and especially against severe illness and death, questions have remained for more than a year.
A new peer-reviewed study published Friday in the Journal of Molecular Biology and featured on the journal’s cover, provides insight to why delta is the most lethal variant of SARS-CoV-2.
Researchers at the University of Colorado performed extensive biophysical analyses on the Delta variant and individual mutations that comprise it. In the lab, they identified the effect of mutated residues from recovered patients.
“Since we have performed individual analyses on these mutations, we have a foundational understanding of how some residues are affecting immune escape and infectivity of SARS-CoV-2."Krishna Mallela
The team says their findings help explain why patients who have been vaccinated are still able to be infected by the new variants and why patients who have contracted the Delta variant are more likely to be hospitalized. They found that delta also shows higher protein expression than previous variants Alpha, Beta and Gamma.
One mutation in the delta variant, T478K, is believed to have evolved from patients who were infected with earlier variants of SARS-CoV-2. This mutation has been shown to escape antibodies generated from previous COVID-19 infections.
“Since we have performed individual analyses on these mutations, we have a foundational understanding of how some residues are affecting immune escape and infectivity of SARS-CoV-2,” said study author and professor in the department of pharmaceutical sciences Krishna Mallel.