Recovering from COVID-19 not enough, new WHO study talks of ‘hybrid immunity'
2 min read . Updated: 22 Jan 2023, 07:46 PM IST
PremiumExperts say that 'immunity' achieved from the combined impact of vaccination and infection provides better protection against severe disease and hospitalisaton from COVID-19.
With the COVID-19 pandemic now moving into its fourth year, more than 668 million cases across the world have made it into official records. But as nations across the globe continue to report fresh cases, researchers have begun talking about “hybrid immunity". Experts say that 'immunity' achieved from the combined impact of vaccination and infection provides better protection against severe disease and hospitalisaton from COVID-19.
According to a recent study that included collaborators from the World Health Organisation, the combination prevented more than 97% of cases from escalating into severe disease or hospitalisation for up to 12 months after infection or initial immunization - whichever was most recent. Boosters conferred an additional 6 months of protection. The effectiveness of previous infection against hospital admission or severe disease was 74·6% at 12 months.
It is pertinent to note here that 13.24 billion doses of vaccine have been administered globally till date.
Those with hybrid immunity after recceiving two shots of COVID-19 vaccine were nearly 42% less likely to be reinfected within a year, and nearly 47% less likely in the six months following their first booster shot. Protection at 12 months was at a mere 25% for those who had been infected but not vaccinated.
With hybrid immunity providing a greater degree of protection, the researchers claim that they could wait six months after infection or vaccination to receive a booster dose.
The report was based on a review of more than two dozen studies between January 2020 and June 2022 on the protection afforded by hybrid immunity and by previous infection alone.
“All estimates of protection waned within months against reinfection but remained high and sustained for hospital admission or severe disease. Individuals with hybrid immunity had the highest magnitude and durability of protection, and as a result might be able to extend the period before booster vaccinations are needed compared to individuals who have never been infected," the study suggested.
The researchers suggested that the information could be used to tailor guidance on the number and timing of SARS-CoV-2 vaccinations.