Insufficient and delayed testing may explain why some European countries, such as Italy and Spain, are experiencing much higher casualty numbers (relative to reported confirmed cases) than Germany, which has detected an estimated 15.6% of infections compared to only 3.5% in Italy or 1.7% in Spain. Detection rates are even lower in the United States (1.6%) and the United Kingdom (1.2%) – two countries that have received widespread criticism from public health experts for their delayed response to the pandemic.
In sharp contrast to this, South Korea appears to have discovered almost half of all its SARS-CoV-2 infections. The authors estimate that on 31 March 2020, Germany had 460,000 infections. Based on the same method, they calculate that the United States had more than ten million, Spain more than five million, Italy around three million and the United Kingdom around two million infections. On the same day the Johns Hopkins University reported that globally there were less than 900,000 confirmed cases, meaning that the vast majority of infections were undetected.