Hybrid Immunity

Why in News?

• Recently, A  study in the journal The Lancet Infectious Diseases held that “hybrid immunity” provides better protection against severe Covid-19, while all immunity against a re-infection wane within a few months.

Highlights

• The study is based on a meta-analysis of 11 other studies on the protective effectiveness of previous SARS-CoV-2 (Covid) infection and 15 studies on the protective effectiveness of hybrid immunity.
• Hybrid immunity from an infection is a combination of natural protection along with the immunity provided by the vaccine.
• It appears to result In stronger protection than just infection or vaccination alone.
• In the case of Covid-19, hybrid immunity is when someone recovers from a Covid infection before getting vaccinated.
• A hybrid Immunity offers a “higher magnitude and durability” of protection as compared to infection alone, emphasizing the need for vaccination.
• However, with the faster-spreading omicron variants leading to more infections and consequently more people developing this hybrid immunity.
• 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.
• This protection stood at 74.6% at 12 months and 71.6% at 15 months.
• Protection against reinfection declined faster, standing at 65.2% at three months and dropping to 24.7% at 12 months and 15.5% at 15 months.
• 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 same can offer 69% protection against reinfection at three months, dropping to 41.8% 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 and 95.3% at six months.