Presentation Information
[MS13-03]Reinfection by pre-Omicron variants of SARS-CoV-2 virus from the epidemiologic perspective: a review of evidences
*Daihai He1, Konstantin Avilov1, Lewi Stone2 (1. The Hong Kong Polytechnic University (Hong Kong), 2. RMIT (Australia))
Keywords:
COVID-19,SARS-COV-2,Reinfection,Delta,Alpha
The ability of all variants of SARS-CoV-2 to reinfect previously infected individuals is proven by many observed examples. But the exact probability of reinfection remains uncertain: some reputable studies indicated a negligible chance of reinfection with pre-Omicron variants, while other highly cited studies found a considerable amount of reinfection cases in the pre-Omicron era.The exact value of the reinfection chance – and, hence, its population-level effect – is critical in estimation of the effectiveness of the anti-COVID-19 vaccination campaign. Modelling studies that analyse the processes in year 2021 assume both “no reinfection” and “substantial reinfection” for the pre-Omicron variants.In this paper, we review and analyse seven studies and datasets indicating a low reinfection rate, and four studies referenced by the modelling studies as proofs of a relatively high reinfection rate.The available “contra-reinfection” evidences and the discovered flaws and misinterpretations in the “pro-reinfection” studies lead us to the conclusion that the reinfection rate in the pre-Omicron era was small, and the reinfection cases usually amounted to as few as 2-5% of all incident cases.