The executive director of the WHO's Health Emergencies Program Michael Ryan said the coronavirus "may become just another endemic virus in our communities, and this virus may never go away."

Ryan spoke to reporters on Wednesday, amid moves by a growing number of countries to ease restrictions imposed to contain the virus.

He stressed the importance of international cooperation to develop vaccines, pointing out that HIV has not gone away, but as therapies and prevention methods have been found, "people don't feel as scared as they did before."

Ryan warned that infection risks remain high in many parts of the world. He said that if countries reopen without systems to detect transmission, it will accelerate, forcing governments to take more lockdown measures.

He said that could lead to a vicious cycle of public health disaster followed by economic disaster.

The World Health Organization has warned there is a long way to go before the coronavirus pandemic is brought under control, reiterating calls for having systems in place to detect new cases.

Ryan noted that as has been seen in some countries, even a small recurrence of the virus can require a serious public health response.