It was three years ago this Saturday that the World Health Organization (WHO) declared covid-19 a pandemic. To mark the date, the director-general, Tedros Ghebreyesus, posted a message on Twitter in which he considered it a "moral imperative" to understand the origins of the coronavirus that in 2020 spread across the globe..

Quoted by the Eco portal, the director-general of the WHO recalls that it was on 30 January 2020 that the organization sounded the alarm about the spread of covid-19, having characterized it as a pandemic on 11 March.

"Three years after the start of the covid-19 emergency, too many lives have been lost. Too many people are still suffering, including from long covid. We will never stop demanding equitable access to life-saving tools," says Tedros Ghebreyesus.

"Understanding the origins of covid-19 and exploring all hypotheses remains a scientific imperative, to help us prevent future outbreaks, and a moral imperative, for the sake of the millions of people who have died and those living with long covid," added the WHO director-general.

The tail of the pandemic continues to be a source of speculation. FBI director Christopher Wray said at the beginning of the month that the American investigation agency had concluded some time ago that the virus came from a laboratory in the Chinese city of Wuhan. An assertion promptly rejected by Beijing.

The pandemic has infected more than 681 million people and caused more than 6.8 million deaths in three years.