References:
1. October 29, 2020 N Engl J Med 2020; 383:e105 DOI: 10.1056/NEJMsr2031592
2. October 21, 2020 DOI: 10.1056/NEJMp2028209
3.https://covid.ourworldindata.org/data/ecdc/new_deaths.csv
4. https://github.com/ytakefuji/US