Recent findings in The Lancet Infectious Diseases journal discuss the concept of “hybrid immunity,” suggesting that it offers superior protection against severe Covid-19. The study, a meta-analysis, synthesizes data from 11 studies on SARS-CoV-2 infection’s protective efficacy and 15 studies on hybrid immunity.
Understanding Hybrid Immunity
Hybrid immunity, in the context of infectious diseases, combines natural immunity from previous infection and vaccine-provided immunity. For Covid-19, this specifically refers to individuals who recover from an infection and then receive the vaccine. This two-pronged immunity approach seems to offer stronger protection than either infection or vaccination alone.
Key Takeaways from the Study
The Lancet’s study offers several important conclusions about hybrid immunity and Covid-19:
Better Protection Against Severe Disease
Hybrid immunity grants substantial and lasting protection compared to infection alone. This underscores the importance of vaccinations. As the Omicron variant rapidly spreads and more people recover from infections, incidence of hybrid immunity is likely to increase.
Efficacy of Hybrid Immunity
Protection against hospitalization and severe disease resulting solely from Sars-CoV-2 infection stood at 82.5% three months after the patient’s last shot or infection, decreasing to 74.6% at 12 months and 71.6% at 15 months. Protection against reinfection dropped more swiftly, beginning at 65.2% at three months and falling to 24.7% at 12 months and 15.5% at 15 months. Comparatively, for those with hybrid immunity, the primary vaccine doses provided 96% protection at three months and 97.4% protection at 12 months. Such immunity gave 69% protection against reinfection at three months, declining to 41.8% at 12 months. Remarkably, hybrid immunity obtained from infection along with primary doses and a booster dose offered 97.2% protection at three months, dipping slightly to 95.3% at six months.
Implications of Hybrid Immunity
This scientific understanding of hybrid immunity can guide vaccine distribution strategies. For areas with high Sars-CoV-2 seroprevalence, focusing on vaccinating people at highest risk for severe disease, such as older individuals and those with comorbidities, can offer robust protection against severe disease and hospitalization for at least one year.
Relating the Study to UPSC Civil Services Examination
In relation to the Covid-19 pandemic context, it’s crucial to understand different types of vaccine platforms. For example, The Serum Institute of India produced the Covishield vaccine using a recombinant-adeno-virus platform, not an mRNA platform, contrary to common belief. The Sputnik V vaccine, approved in 71 countries, is based on a human adenovirus vector platform. Lastly, Covaxin is an inactivated viral vaccine developed with Whole-Virion Inactivated Vero Cell-derived technology. Understanding these differences is essential, and they frequently appear in discussions about public health and medical science.
