Although a number of vaccines are now in phase three clinical trials, there's no silver bullet at the moment and there might never be for COVID-19, the World Health Organization (WHO) chief said on Monday.

WHO Director-General Tedros Adhanom Ghebreyesus told a virtual press conference that for now, stopping COVID-19 outbreaks comes down to the basics of public health and disease control, including testing, isolating and treating patients, and tracing and quarantining their contacts.

"For individuals, it's about keeping physical distance, wearing a mask, cleaning hands regularly and coughing safely away from others -- Do it all," he urged.

The WHO chief told reporters that most people in the world remain susceptible to this virus, even in areas that have experienced severe outbreaks.

In the past weeks the WHO chief has repeatedly stressed that although the world has changed, the basic measures needed to suppress transmission and save lives have not -- find, isolate, test and care for cases, and trace and quarantine their contacts.

"Countries and communities that have followed this advice carefully and consistently have done well, either in preventing large-scale outbreaks -- like Cambodia, New Zealand, Rwanda, Thailand, Vietnam, and islands in the Pacific and Caribbean -- or in bringing large outbreaks under control, like Canada, China, Germany and the Republic of Korea," he said earlier last week.

On July 31, the WHO Emergency Committee on COVID-19 met and reviewed the current pandemic, and based on the advice of the Committee, Tedros announced that the COVID-19 outbreak still constituted a Public Health Emergency of International Concern.