The coronavirus outbreak that started in China has infected more than 20,000 people and killed more than 400.
According to Business Insider, cases have already been recorded in 24 other countries.
Fortunately, most patients have seemed to make full recoveries so far.
However, the Chinese Health Commission warns that even those who've recovered could be at risk of reinfection.
One expert says that's because the antibodies that patients are producing so far don't necessarily last very long.