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

Abstract

To the Editor: The severe acute respiratory syndrome coronavirus 2 (SARSCoV-2) pandemic has globally disrupted contemporary life1. 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 discussed3-5. 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-making6. 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 Turkey7. 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 al7. 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 SARSCoV-2: 41 versus 18%; p<0.001; χ2 test), more mechanical ventilatory support (H1N1 versus SARS-CoV-2: 28 versus 9%; p=0.004; χ2 test), and succumbed more frequently (H1N1 versus SARS-CoV-2 mortality: 8.4 versus 3.2%; p=0.004; χ2 test). Data from Turkey have been properly reported, are plausible, and in accordance with data from the United States reported earlier this year8. 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.