SPUTNIK-V

Subject : Science & tech

Context : Russias’s Sputnik V vaccine 92% effective. No adverse events reported in Phase 3 trials that involved 36,000 volunteers, says its Health Ministry.

Concept :

• 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.
• The russian vaccine has outrun other Covid-19 vaccines like Oxford-AstraZeneca, Moderna and Pfizer which are still in trials.
• 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.