Yongmoon Kim,Bryan Inho Kim,Sangwoo Tak
Response to the comment of Perone by the corresponding author Kim
Response to the comment of Perone by the corresponding author Kim

I agree with Prof. Perone’s comment that his paper was referenced unproperly. His work should have been referenced in the next sentence, which is “or could not control for the effect of SARS-CoV-2 variants, especially during the emergence of the Delta and Omicron variants.” Our intention was to point out that we should consider the effect of COVID-19 variants when comparing different countries’ case fatality rates, complementing Perone’s preceding work, which showed the effect of environmental factors on the case fatality rate [1]. This was a mistake that happened during the revision process, and I offer my apologies to Prof. Perone.