Coronavirus Disease-2019 Case, Death, and Testing Rates in the United States and Worldwide: Primary Data and Review

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection has been associated with a worldwide pandemic. We assessed data as of November 25, 2020 from our combined laboratories and as reported for states in the United States (US) and countries for case, death, and testing rates per million to determine causes of rate differences. SARS-CoV-2 naso-pharyngeal (NP) RNA testing in 1,179,912 subjects in 47 states (39 of which with >100 cases) are reported, with a mean 9.3% positive rate, comparable to the 7.0% rate reported nationwide. In 91 previously positive (2-4 weeks) subjects, NP swab testing was twice as likely to be positive (58.6%) as saliva samples (21.5%). We also documented that NP swabs could remain positive for 6 weeks or longer. Our positive rates per state agreed reasonably well with reported national data (r=0.609, P<0.0001). The highest US case rates per million were in the mid-west; the highest death and testing rates were in the northeast. Of 47 countries, the highest case, death, and testing rates per million were mainly in Europe and the Americas, with the lowest rates in Asia. Correlations between case and death rates and case and testing rates were very different between states (0.076 and -0.093, respectively) and countries (0.763 and 0.600, respectively). In conclusion, outpatient saliva testing was not as sensitive as NP testing for detection, and the marked variability in case and death rates was most likely due to differences in public health measures, viral and human genetic differences and age of cases, rather than due to differences in testing rates.