The World Health Organization (WHO) yesterday said it has approved a Covid-19 vaccine made by drugmaker Sinovac Biotech for emergency use listing, paving the way for a second Chinese shot to be used in poor countries. 

A WHO emergency listing is a signal to national regulators on a product's safety and efficacy. It will also allow the shot to be included in Covax, the global programme to provide vaccines mainly for poor countries, which faces major supply problems due to an Indian export suspension.

The independent panel of experts said in a statement it recommended Sinovac's vaccine for adults over 18, with a second dose 2-4 weeks later. There was no upper age limit as data suggested it is likely to have a protective effect in older people.

Branded CoronaVac in some regions, it is the second Chinese developed vaccine to win such WHO listing to combat COVID-19, after the May 7 approval of a shot developed by state-backed Sinopharm.

Sinovac said that it had supplied more than 600 million doses of its vaccine at home and abroad as of end-May and over 430 million doses have been administered.

Vaccine efficacy results showed that the vaccine prevented symptomatic disease in 51% of those vaccinated and prevented severe Covid-19 and hospitalisation in 100% of the studied population, the WHO said.

The pandemic has killed at least 3,551,488 people worldwide since the virus first emerged in December 2019, according to an AFP compilation of official data.

The US is the worst-affected country with 594,568 deaths, followed by Brazil with 462,791, India with 331,895, Mexico with 223,568 and Britain with 127,782.

Meanwhile, Malaysia imposed a tough nationwide lockdown yesterday to battle a worsening coronavirus outbreak, as countries across Southeast Asia struggled with a resurgence in cases driven by infectious variants.

Much of the region escaped the pandemic's first wave last year relatively unscathed by rapidly closing borders and introducing curbs.

But countries from Thailand to Vietnam are being hammered by fresh surges, with efforts to quell outbreaks hampered by slow vaccine rollouts and populations weary of restrictions.

Malaysia is among the worst hit. Of almost 2,800 deaths from Covid-19 recorded in the country of 32 million since the start of the pandemic, over 40 percent were in May alone.

More than 570,000 infections have been reported, with a string of new daily records last week.

Under what authorities have termed a "total lockdown" in force from yesterday, only essential businesses -- such as supermarkets and medical clinics -- can operate, people can only go outside for necessities, and most schools are closed. Travel between most parts of the country had already been banned for months.

Vietnam was praised for keeping infections low last year, but its cases have more than doubled in the past month, prompting officials to suspend foreign arrivals at some airports and implement social distancing in Ho Chi Minh City.

Overcrowded prisons have been at the centre of an escalating outbreak in Thailand, which is recording more than 4,000 infections a day.

Singapore -- which had barely seen any local transmission for months -- tightened curbs in May following an uptick in cases, with authorities citing concerns about variants.

And the Philippines imposed a fresh lockdown in and around Manila in March as hospitals struggled to cope, although the restrictions have been eased as infections fall.