U-shaped-aggressiveness of SARS-CoV-2: Period between initial symptoms and clinical progression to COVID-19 suspicion. A population-based cohort study

Early identification of different COVID-19 clinical presentations may depict distinct pathophysiological mechanisms and guide management strategies. To determine the aggressiveness of SARS-CoV-2 using symptom progression in COVID-19 patients. Historic cohort study of Mexican patients. Data from January-April 2020 were provided by the Health Ministry. Population-based. Patients registered in the Epidemiologic Surveillance System in Mexico. Subjects who sought medical attention for clinical suspicion of COVID-19. All patients were subjected to RT-PCR testing for SARS-CoV-2. We measured the Period between initial symptoms and clinical progression to COVID-19 suspicion (PISYCS) and compared it to the primary outcomes (mortality and pneumonia). 65,500 patients were included. Reported fatalities and pneumonia were 2176 (3.32%), and 11568 (17.66%), respectively. According to the PISYCS, patients were distributed as follows: 14.89% in 7 days. The distribution for mortality and pneumonia was 5.2% and 22.5% in 7 days, respectively (p