Today marks a grim anniversary as the World Health Organisation (WHO) first announced the initial cases of what turned out to be Covid-19 exactly a year ago.

A tweet was posted by the WHO on January 4, 2020, warning of a "cluster" of pneumonia cases had emerged in Wuhan, China.

Investigations were underway to "identify the cause of this illness", it added.

The virus was later named Covid-19 on February 11, before the WHO declared a pandemic on March 11.

More than 85million cases have now been reported around the world, according to data from the Johns Hopkins University.

The global death toll has reached more than 1.8million, its figures show.

Millions of cases have been reported around the world

Last year, the World Health Organisation tweeted: "China has reported to WHO a cluster of #pneumonia cases —with no deaths— in Wuhan, Hubei Province.

"Investigations are underway to identify the cause of this illness."

The organisation added: "WHO is closely monitoring this event and will share more details as we have them.

"WHO is working across the 3 levels (country office, regional office, HQ) to track the situation."

The virus first emerged in Wuhan, China

The WHO says authorities in China first reported the cases on December 31 2019.

An incident management support team was set up on New Year’s Day 2020, which put the WHO "on an emergency footing for dealing with the outbreak," it added.

It then posted the tweet on January 4.

Since then, countries around the world have been plunged into repeated lockdowns as they struggle to bring the virus under control.

Countries around the world have been hit by coronavirus

But vaccines have also been developed, including the Pfizer and Oxford/AstraZeneca jabs.

According to Johns Hopkins researchers, there have been more than 350,000 deaths in the US, over 195,000 in Brazil and nearly 150,000 deaths in India.

So far, the total number of deaths in the UK has passed 75,000.

The Daily Star reported on the initial outbreak in China on January 1 last year, when there were just 27 cases of the virus.

By the end of the month, there were warnings that a global pandemic was "inevitable".

The Chinese whistleblower doctor who first raised concerns about the virus in December 2019, Li Wenliang, died of Covid in February last year.

He had warned fellow medics on December 30, 2019.

But he was later warned by police to stop "making untrue comments" that had "severely disturbed the social order".