NEW DELHI: A latest study has shown that reinfection in Covid-19 is rare and natural infection appears to elicit strong protection against reinfection with an efficacy of nearly 95 per cent for at least seven months.
This comes a day after a research published in the Lancet said that while those with previous history of infection may be protected for a long time, protection drops dramatically for people over the age of 65.
The study called “SARS-CoV-2 reinfection in a cohort of 43,000 antibody-positive individuals followed for up to 35 weeks” done in Qatar, which has significance for other countries too, has shown that while the incidence rate of reinfection was 0.66 per 10,000 people in those who were antibody positive, it was 2.15 per 10,000 people in those never infected before.
Based on this, researchers have concluded that the efficacy of natural infection against reinfection could be about 95.2%.
They also noted that reinfections were less severe than primary infections and only one reinfection was severe, two were moderate, while none were critical or fatal.
Most reinfections 66.7% were diagnosed through random or routine testing, or through contact tracing.
Incidentally, this study comes after another research titled “Assessment of protection against reinfection with SARS-CoV-2 among 4 million PCR-tested individuals in Denmark in 2020: a population-level observational study” was published in The Lancet.
This study found the protection in general population to be 80 per cent or higher in those under 65, but approximately 47 per cent in those aged 65 and older, meaning they were more likely to be infected again.
“Our estimates for overall protection after the previous infection are in line with several other cohort studies,” noted the scientists.