The US remains the most heavily affected country by the COVID-19 pandemic, with more than 1.7 million total confirmed cases. In comparison, South Korea is now thought to be in the recovery phase of this disease with more than 11,500 total confirmed cases. Though the US has now performed 40 COVID-19 tests per 1,000 population in contrast to 15 tests per 1,000 population performed in South Korea, it is the timing of these tests which has proved vital in slowing the transmission of this disease, says GlobalData, a leading data and analytics company.

Katie Wrenn, MPH, Associate Epidemiologist at GlobalData, comments: “Though the US has now ramped up its testing capabilities and performed the largest number of tests in comparison to any other country globally, this should have been done much earlier to have a more profound effect.”

South Korea and the US both identified their first case around the same date, 20 January 2020 and since then have each followed very different trajectories.

GlobalData epidemiologists analyzed the total prevalence and test rate of COVID-19 in South Korea and the US from 22 January 2020 to 22 May 2020. Initially, South Korea reported higher infection rate than the US, with 160 cases per 1 million population reported on the 15 March 2020, in comparison to 11 per 1 million population reported in the US.

However, in the US, from the 15 March 2020 there has been exponential growth in the number of cases per 1 million population to the current figure of 5,000 cases per 1 million population.

Wrenn continues: “A series of issues related to rolling out mass testing probably explains the lower number of total confirmed cases initially reported in the US compared to South Korea. In the first few months of infection, the disease was thought to be silently spreading throughout the US due to the lack of widespread testing.”

Mass testing in South Korea was in place long before the country reached its epidemiological peak, whereas in the US, mass testing has only just recently been introduced. After experiencing the Middle East Respiratory Syndrome outbreak in 2015, South Korea already had a system in place for testing a novel virus. Therefore, broad testing measures, combined with speedy isolation of cases and contact tracing, were performed quickly after diagnosing their first case.

Wrenn concludes: “South Korea has gained much greater control of COVD-19 than the US, therefore public health agencies should consider early testing in slowing the spread of disease for future viral outbreaks.”