20-Jan-2023: “Hybrid immunity” provides better protection against severe Covid-19: The Lancet Infectious Diseases
Hybrid Immunity is a combination of natural protection and vaccine-induced immunity.
Study: Meta-analysis of 11 studies on protection from previous SARS-CoV-2 infection and 15 studies on hybrid immunity
Highlights:
Better protection: Higher magnitude and durability than infection alone
Faster-spreading of omicron variants is leading to more infections and consequently more people developing this hybrid immunity.
Efficacy of Hybrid Immunity:
Protection against severe disease and hospitalizations:
- 82.5% at 3 months after last shot/infection
- 74.6% at 12 months
- 71.6% at 15 months
Protection against reinfection:
- 65.2% at 3 months
- 24.7% at 12 months
- 15.5% at 15 months
Hybrid immunity with primary vaccine doses:
- 96% at 3 months
- 97.4% at 12 months
- 69% protection against reinfection at 3 months
- 41.8% at 12 months
Hybrid immunity from infection + primary + booster dose:
- 97.2% at 3 months
- 95.3% at 6 months
Implications:
- Tailor guidance on number and timing of SARS-CoV-2 vaccinations
- Primary vaccination in regions with high sero-prevalence offers high protection against severe disease and hospitalisation for at least one year.