NEW YORK CITY – “Natural immunity” granted by previous COVID-19 cases can provide protection that is comparable to Moderna and Pfizer-BioNTech’s mRNA vaccines, according to a new study that was released last week.
The study, entitled “Past SARS-CoV-2 infection protection against re-infection: a systematic review and meta-analysis,” was conducted by a group of researchers that make up the COVID-19 Forecasting Team, and was published in The Lancet on February 16.
Researchers analyzed a total of 65 studies across 19 countries.
Infection by the original strain of COVID-19 – as well as the alpha, beta and delta variants – yielded the most protection from reinfection, which remained at over 78 percent effective 40 weeks later.
However, the protection granted by “natural immunity” was less robust against the omicron BA.1 variant, which dropped to 36.1 percent effectiveness 40 weeks after infection.
Protection against severe cases of COVID-19 that could result in hospitalization or death also enjoyed enhanced protection – even against omicron variants – of 78 percent or more 40 weeks later.
The level of protection did decline over time, however, with effectiveness dropping the fastest against the omicron variant.
The study indicates that “natural immunity” granted by previous COVID infection offers comparable protection to two doses of mRNA vaccines.
“This finding also has important implications for the design of policies that restrict access to travel or venues or require vaccination for workers,” the study says. “It supports the idea that those with a documented infection should be treated similarly to those who have been fully vaccinated with high-quality vaccines.”