WHO Director General Tedros Adhanom Ghebreyesus | Valentin Flauraud/EPA

“A number of vaccines are now in phase three clinical trials and we all hope to have a number of effective vaccines that can help prevent people from infection,” WHO Director-General Tedros Adhanom Ghebreyesus said this week, adding that the international scramble for a vaccine was also “unprecedented”.

“However, there’s no silver bullet at the moment – and there might never be,” he said, underscoring uncertainties.

“There are concerns that we may not have a vaccine that may work, or its protection could be for just a few months, not more. But until we finish the clinical trials, we will not know.”

“The message to people and governments is clear: ‘Do it all’,” Ghebreyesus said of the novel coronavirus, which has killed more than 690,000 people and infected at least 18 million.

“By wearing a mask, you’re sending a powerful message to those around you that we’re all in this together”.

“Wear a mask when appropriate, keep your physical distance from others and avoid crowded places, observe coughing etiquette, clean your hands frequently and you’ll be protecting yourself and others.”