As the coronavirus spreads widely around the world, scientists are starting to use a powerful new tool: a blood test that identifies people who have previously been exposed to the virus. The test is still under development in the United States, but has been rolled out for use in Singapore and China, the two current worst infected places right now.
The current lab test used in the US only identifies people who are actively spreading the virus that causes COVID-19. Which is crucial information, but doesn’t reveal who had previously been infected. Which is important for understanding the unfolding epidemic.
