Individuals who were previously infected with COVID-19 are at least as well-protected against severe disease in the long run and may even have better protection, according to a recent study published in The Lancet.
The study reviewed 65 different findings on natural immunity, with the results suggesting that natural immunity is at least 88% effective against hospitalization and death from all COVID-19 variants, for around 10 months after infection.
However, the study did not account for the XBB.1.5 subvariant, also known as Omicron. Natural immunity provided less protection against the BA.1 subvariant of Omicron, which recorded a 36% efficacy against symptomatic infection after 10 months.
Despite the significant findings, the research team continued to encourage the use of COVID vaccinations as a method of acquiring immunity against COVID-19, despite widespread concern about potential side effects.
“Vaccination is the safest way to acquire immunity, whereas acquiring natural immunity must be weighed against the risks of severe illness and death associated with the initial infection," said lead author Stephen Lim, from the Institute for Health Metrics and Evaluation at the University of Washington’s School of Medicine.
“Vaccines continue to be important for everyone in order to protect high-risk populations such as those who are over 60 years of age and those with comorbidities,” added fellow author Caroline Stein.
“This also includes populations that have not previously been infected and unvaccinated groups, as well as those who were infected or received their last vaccine dose more than six months ago," she continued. "Decision makers should take both natural immunity and vaccination status into consideration to obtain a full picture of an individual’s immunity profile.”
Meanwhile, a separate study by the World Health Organization (WHO) similarly found that hybrid immunity is the best means of protection against COVID-19. Hybrid immunity offers a mix of protection from COVID-19 vaccination and natural infection, with an efficacy rate of 97% at preventing severe COVID-19 and hospitalization for fully vaccinated individuals, one year after their most recent infection or vaccination.
The study also found that those with previous infection and no vaccinations had nearly 75% efficacy against severe disease and hospitalization a year after their infection or last vaccine dose.
“The analysis shows that hybrid immunity provides higher protection, demonstrating the advantages of vaccination even after people have had COVID-19,” WHO said in a statement. “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."