From UPSC perspective, the following things are important :
Prelims level : Covaxin and Covishield
Mains level : Paper 2- Breakthrough infections
- ICMR said that a small fraction of those vaccinated with either Covaxin or Covishield have tested positive (i.e. breakthrough” infections).
- However, these instances do not undermine the efficacy of the vaccines.
- The immune response begins to develop usually two weeks after every dose and there are variations within individuals, too.
- Of the 9.3 million who received the first dose of Covaxin, 4,208 tested positive; and of the 1.7 million who received the second dose, 695 tested positive.
- For Covishield, of the 100.3 million who received the first dose, 17,145 tested positive; and of the 15 million who got the second dose, 5,014 tested postive.
What explains infections after vaccination
- Healthcare and frontline workers, who were among the first to be vaccinated, were as a population far more exposed to the virus and therefore more susceptible.
- Secondly, the emergence of “the highly transmissible second wave (newer variants) ” may have contributed to instances of infection among those vaccinated.
- Several variants, which have mutations that have been shown to avoid detection by the immune system, and in some cases reduce the efficacy of vaccines, have been reported globally, including in India.