The WHO said Tuesday that one strain of a Covid-19 variant first detected in India was now considered "of concern" and had been dubbed "Delta", while two other strains had been downgraded.

The B.1.617 variant of the virus, which has in part been blamed for India's explosive outbreak, has been called a triple mutant variant since it is split into three lineages.

The UN health agency last month declared the entire strain a "variant of concern", or VOC, but on Tuesday, it said only one of the sub-lineages deserved that label.

"It has become evident that greater public health risks are currently associated with B.1.617.2, while lower rates of transmission of other lineages have been observed," the World Health Organization said in its weekly epidemiological update on the pandemic.

The B.1.617.2 variant remains a VOC, along with three other variants of the virus that are seen as more dangerous than the original version because they are more transmissible, deadly or have the potential to get past some vaccine protections.

In line with a decision announced Monday to refer to variants of concern and interest using Greek letters -- aimed to avoid the possible stigmatisation associated with referring to them with the name of the countries where they were first detected -- the B.1.617.2 variant has now been dubbed Delta.

"We continue to observe significantly increased transmissibility and a growing number of countries reporting outbreaks associated with this variant," the UN agency said.

"Further studies into the impact of this variant remain a high priority for WHO."

In fact, a new variant announced by Vietnam's health authorities on Saturday appears to be a variation of Delta.

"What we understand is that it is this B.1.617.2 variant with one additional deletion in the location of the spike protein," WHO's technical lead on Covid-19 Maria Van Kerkhove told reporters Tuesday.

"We know that the B.1.617.2, the Delta variant, does have increased transmissibility, which means it can spread easier between people," she added.

The B.1.617.1 sub-lineage has meanwhile been downgraded to a "variant of interest," and named Kappa.

And the B.1.617.3 is now not even considered a variant of interest, WHO said, since "relatively few reports of this variant have been submitted to date."

It has not been attributed a Greek letter.

RECORD DEATHS IN MALAYSIA

The coronavirus has killed at least 3,681,985 people since the outbreak emerged in China in December 2019, according to a tally from official sources compiled by AFP yesterday.

The Australian state of Victoria yesterday extended a snap coronavirus lockdown in its capital of Melbourne for a second week, as it scrambles to rein in a highly contagious variant first detected in India, but will ease some curbs elsewhere.

Last Thursday's lockdown in Australia's second most populous state was to have run until today, following the detection of the first locally acquired cases in three months, but infections rose and the number of close contacts reached several thousand.

Malaysia reported 126 deaths from the coronavirus yesterday, the highest daily toll since the start of the pandemic, reports Reuters.

The Southeast Asian nation is seeing a surge in Covid-19 cases, partly due to more infectious variants, and has imposed stricter lockdown measures that have shut down non-essential businesses.

Britain was in talks with Oxford and AstraZeneca (AZN.L) for additional doses of their Covid-19 vaccine that has been modified to better target the "beta" coronavirus variant first identified in South Africa, and it will fund trials of the shots.

Britain has previously secured 100 million doses of the vaccine, developed at the University of Oxford and licenced to AstraZeneca, and the health ministry said the extra doses under discussion would be tailored to target the B.1.351 variant.

Israel's Health Ministry said on Tuesday it had found the small number of heart inflammation cases observed mainly in young men who received Pfizer's Covid-19 vaccine in Israel were likely linked to their vaccination.

Pfizer has said it has not observed a higher rate of the condition, known as myocarditis, than would normally be expected in the general population.

Meanwhile, Secretary of State Antony Blinken said on Tuesday the United States will announce in the next two weeks how it plans to distribute 80 million Covid-19 vaccine doses it has pledged globally.

Speaking at a joint news conference with Costa Rican President Carlos Alvarado, Blinken said the administration of US President Joe Biden would focus on equitable distribution of the vaccines and not tie political strings to the process, a criticism at times directed at China.

"Sometime in the next week to two weeks – we will be announcing the process by which we will distribute those vaccines, what the criteria are, how we will do it," Blinken said during his first trip as secretary of state to Latin America, which is fighting to contain Covid-19.