- December 11, 2021
- Posted by: admin1
- Category: DPN Topics
Subject – Science and Tech
Context – Health Ministry said India is still examining the possibility of administering booster shots of the Covid-19 vaccine
- Most Covid vaccines are administered in two doses, with a few given as a single dose. A booster is an additional shot given after the protection provided by the original shot(s) has begun to decrease over time, so that people can maintain their level of immunity for longer.
- Antibodies decay over time, and even memory T-cells will die after a few years or months.
- In the past, boosters were recommended for smallpox prevention every three to five years. Tetanus toxoid boosters are also recommended today for adults and pregnant women after childhood vaccination.
- If community transmission is high, boosters would help in controlling viral spread.
Case of Omicron Variant
- Omicron — the fifth variant of concern declared by the World Health Organization (WHO) — has a greater ability than previous variants to partially escape protection from Pfizer Inc vaccine.
- The “escape” was incomplete in vaccinated participants who had a previous infection, the paper noted.
- Previous infection, followed by vaccination or booster is likely to increase the neutralisation level and confer protection from severe disease in Omicron infection.
- A vaccine imitates an infection — it activates the body’s immune system to produce antibodies and memory T-cells without causing illness. Antibodies are the body’s first response to fight on getting infected, while T-cells protect against severe disease.