One of the worst-case scenarios in the coronavirus pandemic is if the pathogen manages to mutate at a pace that outmatches our ability to create treatments and vaccines for it. Now Bloomberg News reports that there are signs in China that the virus is indeed changing. Qiu Haibo, one of China’s top doctors, told state television that patients in northern regions are responding differently to their infections when compared to the original patients in Wuhan. He said the new patients seem to be taking longer than the one or two weeks seen in Wuhan to develop symptoms after infection, appear to be carrying the virus for longer, and are taking more time to test negative. “The longer period during which infected patients show no symptoms has created clusters of family infections,” said Qiu. However, some earlier research suggesting that the virus is quickly mutating to become even more contagious has been accused of being overblown.