Deciphering SARS-CoV-2 mortality: H1N1 as an aid

Abstract

To the Editor:The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has globally disrupted contemporary life 1 . It has caused 73,996,237 confirmed cases and 1,663,474 deaths since December 19, 2020, with a global mortality rate of 2.25% 2 . While efforts to understand, cure, and prevent the disease are ongoing, the mortality rate and disease burden imposed by SARS-CoV-2, as well as the appropriateness of pandemic containment measures, are also being discussed [3][4][5] . To this end, geographic distributions of disease burden and disease-specific mortality are often key to understand disease vulnerabilities, formulate policies, and aid in opinion-making 6 .In this issue of Revista da Associação Médica Brasileira, Kant and colleagues report on their multi-center retrospective experience with 143 patients with H1N1 and 309 patients with SARS-CoV-2 from seven centers in Turkey 7 . Among their pertinent findings related to the clinical profiling of the two diseases, one result is striking: in their hands, H1N1 was more lethal than SARS-CoV-2! In more detail, Kant et al 7 . report that although H1N1 patients required fewer hospitalization days compared with SARS-CoV-2 patients (mean±SD: 4.4±5.7 versus 10.9±7.6 days; p<0.001; Mann-Whitney U test), they actually required more intensive care support (H1N1 versus SARS-CoV-2: 41 versus 18%; p<0.001; χ 2 test), more mechanical ventilatory support (H1N1 versus SARS-CoV-2: 28 versus 9%; p=0.004; χ 2 test), and succumbed more frequently (H1N1 versus SARS-CoV-2 mortality: 8.4 versus 3.2%; p=0.004; χ 2 test). Data from Turkey have been properly reported, are plausible, and in accordance with data from the United States reported earlier this year 8 .To put the work of Kant et al. 7 into perspective, the author analyzed current SARS-CoV-2 data and compared them with global H1N1 data obtained after the end of the H1N1 pandemic, in the 27 most heavily affected countries (Table 1) 2,9 .