CNBC reports that the epicenter of the coronavirus outbreak is at risk of shifting constantly, posing challenges to public health systems, a health expert said.

"The epicenters will shift constantly," said Teo Yik Ying, dean at the Saw Swee Hock School of Public Health at the National University of Singapore.

Although the U.S. is now seen as the epicenter of the outbreak with cases surpassing 200,000 - "in a month's time, the epicenter will shift," Teo told CNBC.

"Would it shift to South Asia? Would it shift to Africa or Latin America? We don't know at the moment, but there is that real risk that the epicenters will continue to shift, and it could possibly even shift back to East Asia," Teo said.

China has seen more and more cases being imported from overseas, prompting the government there to close its border to foreigners.

A similar trend is also being observed in Singapore, which is witnessing another wave of infections brought in by sick residents returning from overseas.

"This is really the fear for what will be seeding the second wave, that countries that are still suffering the brunt of the coronavirus infection will be exporting people with the virus," said Teo, who emphasized international coordination in managing the pandemic.

The epicenter could continue shifting until people develop herd immunity, said Teo.

Until there is a viable vaccine, it is important to spread out the epidemic to allow time for the healthcare system to recover, said Teo.