Δδ My take on the Delta Variant δΔ
✌🏼 doses provides strong protection against hospitalization and 👆🏼 dose leaves you vulnerable to symptomatic disease. Finish your dosing schedules!
The Delta Variant (previously known as B.1.617.2) is relatively new, so data assessing transmissibility, disease severity, and vaccine escape will continue to be refined in the coming weeks.
From the latest Technical Briefing in England, 2 doses is 79% effective at preventing symptomatic disease and 96% effective at preventing hospitalization (all vaccines). One dose still provides decent protection from hospitalization (80%) but very weak protection (35%) against overall disease.
Because it has taken over other lineages so rapidly it appears to have a strong transmissibility advantage over other variants.
It contains several common mutations in the RBD of the spike protein (452R and 478K) that affect vaccine escape. Importantly, it is missing the 484K/Q mutation that has shown to escape vaccine-induced immunity the strongest in other variants.
It also contains a mutation (681R) near the furin cleavage site that likely impacts virus/cell fusion, resulting in increased Infectivity.
References:
▪️Summary: What scientists know about new, fast-spreading coronavirus variants. Nature News. May 24, 2021.
▪️Vaccine effectiveness: SARS-CoV-2 variants of concern and variants under investigation in England. Technical Briefing 17. June 25, 2021. Page 39.
▪️Other mutations: The Spike of Concern – The Novel Variants of SARS-CoV-2. Viruses. May 27, 2021.
▪️P681R: SARS-CoV-2 spike P681R mutation enhances and accelerates viral fusion. BioXRiV. June 17, 2021.
▪️484: Sensitivity of SARS-CoV-2 B.1.1.7 to mRNA vaccine-elicited antibodies. Nature. March 11, 2021.
Posted on Instagram on June 28, 2021.