Authors of a large peer-reviewed study of natural immunity protection from COVID-19 in Qatar – a relatively small and heavily surveilled population of less than 3 million people – claimed in a letter published by the New England Journal of Medicine on Wednesday that previously infected individuals were exceedingly unlikely to be infected a second time.
Qatar Study Authors: Natural Immunity is Effective Against Known Variants
The authors also reported their research shows that natural immunity provides broad and durable protection, at least comparable to vaccines, against a variety of variants.
Even natural immunity, however, is more vulnerable to the highly transmissible – but less virulent – omicron variant, which now is dominating caseloads and overcresting some of the world’s most heavily vaccinated populations.
90% Protective Against Alpha Reinfection, Approximately 60% Effective Against Omicron
“Overall, in a national database study in Qatar, we found that the effectiveness of previous infection in preventing reinfection with the alpha, beta, and delta variants of SARS-CoV-2 was robust (at approximately 90%), findings that confirmed earlier estimates” the authors wrote. “Such protection against reinfection with the omicron variant was lower (approximately 60%) but still considerable
The authors added, “In addition, the protection of previous infection against hospitalization or death caused by reinfection appeared to be robust, regardless of variant.”
Peer-Reviewed Study Based on Large Proportion of Small, Highly Surveilled Population
The now peer-reviewed study, first covered by TrialSite News while it was a pre-print, found that out of 353,326 COVID-19 cases, only 1,304, or 0.37% of all cases, led to reinfections.
The authors exploited a national, federated database that includes all SARS-CoV-2 data since the pandemic’s inception. An observational study, the authors investigated the risk of severe disease and mortality associated with reinfection compared to primary infection data between February 28, 2020 and April 28, 2021, excluding 87,547 people with a vaccination record.
Drs. Hamad E. Al-Romaihi and Mohamed H. Al-Thani, Roberto Bertollini of the Ministry of Public Health, Abdullatif Al-Khal of Hamad Medical Corporation, Patrick Tang, Sidra Medicine and Weill Cornell Medicine researcher Laith J. Abu-Raddad, who holds a doctorate degree were among the letter’s co-signers and original study’s authors.
Despite its growing recognition across the world, natural immunity has long been a political issue in the United States and is still unrecognized by President Joe Biden’s administration.
The rise of omicron, in particular, will likely lead to wide-scale natural immunity as the less-lethal virus is tantamount to a natural vaccine, reaching broad populations far more efficiently and with more efficacious protective effects than any of the current crop of vaccines.