This May 8, 2021 photo, shows a sign of the World Health Organization (WHO) at the entrance of their headquarters in Geneva amid the coronavirus outbreak. (FABRICE COFFRINI / AFP)

The World Health Organization approved on Tuesday a COVID-19 vaccine from Chinese drugmaker Sinovac Biotech for emergency use, a decision that boosts confidence in the global fight against COVID-19, officials said.

Sinovac said that, as of late last month, over 430 million doses had already been administered in China and abroad

Sinovac's vaccine, called Corona-Vac, is the second China-made COVID-19 jab to gain authorization from the world health body, after a separate formulation from drug company Sinopharm was validated in early May.

The Sinovac vaccine is already in use in many nations whose own health authorities have granted approval for the jab. The recent move by the WHO means the jab may now be used as part of the international COVAX project, which oversees the equitable distribution of vaccines around the globe, especially in developing regions.

WHO officials stressed the important role that Chinese vaccines are set to play. China is manufacturing the Sinovac and Sinopharm vaccines in large quantities, and they can be stored at normal refrigeration temperature for extended periods, making them ideal for distribution in areas that lack sufficient cold-chain infrastructure.

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"The world desperately needs multiple COVID-19 vaccines to address the huge access inequity across the globe," said Mariangela Simao, who is the WHO assistant director-general for Access to Health Products.

"We urge manufacturers to participate in the COVAX facility, share their know-how and data and contribute to bringing the pandemic under control."

The approval has also been lauded by officials from the Philippines and Chile. On Wednesday, Philippine presidential spokesman Harry Roque said in a statement that the approval will boost the vaccine confidence among Filipinos. The country approved the vaccine for emergency use in February.

In South America, Chile's Deputy Health Minister Paula Daza said: "The fact that the WHO approves a vaccine such as Sinovac's allows us to offer more confidence worldwide in a vaccine that we know is very effective."

Severe delays

Health experts have warned that distribution of Chinese vaccines under COVAX cannot come soon enough, as the project has been hit by severe delays to supply.

"Sinovac could have quite a big impact because it can be stored closer to room temperature, so you can use it in remote regions of the world quite easily," Caroline Casey, lead COVID-19 analyst at science analytics company Airfinity, said.

COVAX had hoped to ship 252 million COVID-19 vaccines in the first half of this year, although as of Monday, just 77 million shots have been distributed.

The project is heavily reliant on vaccines manufactured in India, which imposed an export ban earlier this year in order to combat severe domestic outbreaks, leading to a shortfall in supply.

On Tuesday, the WHO said efficacy results for the Sinovac jab showed the vaccine prevented symptomatic disease in 51 percent of those vaccinated, and prevented severe COVID-19 and hospitalization in 100 percent of the studied population.

Real-world data

Real-world data shows that efficacy in preventing symptomatic disease may be higher than trials suggest.

Last month, Indonesia's health ministry said the vaccine showed 94 percent efficacy in preventing symptomatic infection in 120,000 vaccinated healthcare workers.

On advice from its Strategic Advisory Group of Experts on Immunization, the WHO recommended use of the Sinovac vaccine in people aged 18 and older, in a two-dose schedule, with a spacing of two-to-four weeks.

While few adults over the age of 60 years old were involved in late-stage clinical trials for the Sinovac vaccine, the WHO said it is not recommending an upper age limit for the vaccine.

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This is because the vaccine is already in use in many nations, and data from national health authorities suggests the vaccine is likely to have a protective effect in older people.

Sinovac said that, as of late last month, over 430 million doses had already been administered in China and abroad.

Along with the Sinovac and Sinopharm jabs, the WHO has so far given emergency approval to vaccines from Pfizer, Moderna, Astra-Zeneca, and Johnson & Johnson. Clinical trial data has been submitted for a third Chinese vaccine, from CanSino Biologics.

Xinhua contributed to this story.