- February 3, 2021
- Posted by: admin1
- Category: DPN Topics
Subject : Science & technology
Context : An interim analysis of data from the phase 3 trial of the Covid-19 vaccine from Russia — Gam-COVID-Vac, or Sputnik V — suggests that a two-dose regimen offers 91.6% efficacy against symptomatic Covid-19.
- The vaccine has been called Sputnik V, named after the first artificial Earth satellite, Sputnik-I launched by the Soviet Union.
- It is the first Covid-19 vaccine to be approved.
- This vaccine has been developed by Moscow’s Gamaleya Institute in collaboration with the Russia’s defence ministry.
- The vaccine is based on the DNA of a SARS-CoV-2 type adenovirus, a common cold virus.
- The vaccine uses the weakened virus to deliver small parts of a pathogen and stimulate an immune response.
- The vaccine is administered in two doses and consists of two types of a human adenovirus, each carrying an S-antigen of the new coronavirus, which enter human cells and produce an immune response.
Adenovirus Vector Vaccine :
- In this vaccine, adenovirus is used as a tool to deliver genes or vaccine antigens to the target host tissue.
- Adenovirus: Adenoviruses (ADVs) are DNA viruses ranging from 70-90 nanometre in size, which induce many illnesses in humans like cold, respiratory infection etc.
- Adenoviruses are preferred for vaccines because their DNA is double stranded which makes them genetically more stable and the chances of them changing after injection are lower.
- Rabies vaccine is an adenovirus vaccine.
- However, there are drawbacks of adenovirus vector vaccines like pre-existing immunity in humans, inflammatory responses etc.
- Just as human bodies develop immune responses to most real viral infections, they also develop immunity to adenoviral vectors.
- Since adenoviral vectors are based on natural viruses that some humans might already have been exposed to, these vaccines might not work for everyone.