Earlier this week, a special case of COVID-19 in Beijing commanded the attention of doctors. A person returning from the U.S. showed symptoms after finishing quarantine. Three family members of this patient were infected, with 60 more close contacts under observation.

Dr. Ning Yi, an epidemiologist in China, told CGTN that's not surprising. "The disease incubation, that means from infection to a symptom shows up. The time is 42 days; therefore, based on this, it's not surprising to me, especially for Beijing with 20 million people in one city and many international travelers."

"So we have to think about the risk is not zero. And it's a challenge, but it's possible," he added.

Dr. Ning thinks it's not necessary to change control measures, which are already strict enough now, as people have to return to normal life.

"We have to think about the tradeoff between infection control and our normal life. Even there are a few cases in Beijing; I'm very confident it does not create a big issue for Beijing. Even there is a small epidemic or a few cases, Beijing can well control the disease. Therefore, for most people, we have to think about how we can (get) back to our normal lives. Just leave the (matter of) how to control, to the health professionals," he said.

But there is a reminder to travelers. "Here I'd like to remind the international travelers, you have to be very cautious. And when you come back from other countries, please follow government regulation strictly. Therefore we can well control the risk and keep Beijing safe," Ning said.