South Korean Army Disinfects Train Station in Daegu

CORONAVIRUS: The South Korean military assists in a decontamination operation at Dongdaegu station, Saturday, February 29, as part of the fight against the coronavirus outbreak.
READ MORE: The novel coronavirus, which originated in Wuhan, China, has infected more than 81,000 people worldwide and killed nearly 3,000. Those numbers have been a critical gauge of the infection’s spread, but they do not reflect the entire problem. Scientists consider several key questions when assessing the danger posed by the outbreak.

Almost all of the confirmed cases so far have been in China, with about 3,000 scattered around the rest of the world. In China, Beijing changed the testing criteria multiple times, leading to fluctuating numbers that have made it difficult to determine the outbreak’s growth. Outside China, some countries have reported faulty test kits or long delays in getting results. One large study in China found that more than 80% of the cases are mild, and some infected people show no symptoms. This means the number of infected could be much higher than the official tally.