Hybrid Immunity provides better protection against severe Covid-19, while all immunity against re-infection wanes within a few months. This was revealed by a recent study in the journal The Lancet Infectious Diseases.

 

What is hybrid immunity?

  • Hybrid immunity is gained from a previous infection plus vaccines – either the primary doses or both primary and booster doses.
    • As per the recent study, a hybrid immunity offers a higher magnitude and durability of protection as compared to infection alone.
    • Getting a natural infection – best after vaccination so that the risk of death is lower – provides better protection than vaccines alone.
  • This is because it prepares the body against the entire virus, rather than say just the spike protein.

 

What did the study find?

  • Protection against severe disease and hospitalisations from a Sars-CoV-2 infection alone was found to be 82.5% at three months after the last shot or infection.
  • In comparison, hybrid immunity with just the primary vaccine doses was found to be 96% at three months and 97.4% at 12 months.
  • The effectiveness of hybrid immunity gained from infection coupled with the primary as well as a booster dose stood at 97.2% at three months.

 

Why hybrid immunity is effective?

  • Natural immunity (obtained after being infected) comes when the body produces antibodies to protect against a germ or virus.
    • According to WHO, risk of reinfection is relatively low for the six months following infection and then begins to wane over time.
  • Vaccines also introduce antibodies to the body, which helps the immune system learn to produce specific antibodies to fight against Covid.
  • So, when these two immunities are paired together, they provide greater immunity than if they were apart.

 

Implications

  • Guidance on the number and timing of SARS-CoV-2 vaccinations — These results provide information that can be used to tailor guidance on the number and timing of SARS-CoV-2 vaccinations. In regions with high Sars-CoV-2 sero-prevalence, the primary vaccination can offer high protection against severe disease and hospitalisation for at least one year.
  • Indians are relatively safer against severe impacts — This is because nearly 70% of population have been infected at least once with the virus and 95% of the adults have received at least two doses of vaccination.
  • India did not see a surge as was reported in other countries like China and Japan — The finding boosts the theory that the high hybrid immunity level is the reason India did not see any surge when it was being reported in other countries like China and Japan.