SARS-CoV-2 Delta Variant Resistant to Neutralization by Antibody
- The SARS-CoV-2 B.1.617, also known as the delta variant, was originally discovered in India and is now spreading worldwide.
- The delta variant became dominant in parts of India and the United Kingdom, and further spread to other countries.
- The Delta variant had been detected in more than 80 countries, continues to mutate as it spreads, and now makes up 10 percent of all new cases in the United States.
- Delta variant has 3 major subtypes, harboring a variety of spike mutations in the N-terminal domain (NTD) and the receptor-binding domain (RBD) which can increase their ability to evade the immune system.
- Delta variant is speculated to propagate faster than other variants.
- Researchers isolated infectious Delta strain from a person who visited India.
- They examined the Delta variant’s sensitivity to monoclonal antibodies as well as to antibodies in sera from COVID-19 convalescent or vaccinated individuals.
- Researchers discovered that the Delta variant was resistant to anti-NTD and anti-RBD monoclonal antibody neutralization which includes Bamlanivimab.
- Bamlanivimab is an experimental medicine currently being studied for use in treating diseases caused by a coronavirus.
- Sera isolated from patients who recovered from COVID-19 were 4 times less potent against the Delta variant when compared to the Alpha variant.
- Vaccinated individuals who received one dose of Pfizer or AstraZeneca vaccines barely prevented the Delta variant.
- Two-dose administration generated a neutralizing response in about 95 percent of individuals with concentration 3 to 5 times lower against Delta when compared to Alpha.
- The spread of the Delta variant is related with an escape to antibodies targeting non-RBD and RBD spike epitopes.