GENEVA: Two Chinese coronavirus jabs are safe and effective, WHO experts said Wednesday after reviewing partial data, providing a potential boost to countries from Australia to Europe struggling to roll out vaccines fast enough.

Fewer than 600 million jabs have been given out across the world, three months after vaccination programmes began in earnest in Western countries and leaders hailed the drugs as the only safe way out of punishing lockdowns.

Vaccine specialists at the World Health Organization did not issue any advice on how to use China’s jabs, saying they would wait until a decision had been taken on whether to grant them emergency licences.

The experts said the vaccines from Sinovac and Sinopharm “lacked data” for older age groups and people with medical conditions other than Covid.

Another vaccine maker, Pfizer-BionTech, was pushing ahead with its plans to ramp up production and rollout — saying on Wednesday new data from the US showed its jab was 100 percent effective on 12 to 15-year-olds.

The firm said it wanted to start vaccinating youngsters in the US before the start of the next school year. The US has already rolled out almost 150 million vaccines doses, far more than any other country. But it has also suffered more than 550,000 deaths, the highest death toll in the world.

Globally, the virus has killed more than 2.8 million people since it emerged in the Chinese city of Wuhan in late 2019.

Large parts of Europe are battling high infection rates, with most of the continent still living under lockdowns or other restrictions. French President Emmanuel Macron, who has repeatedly vowed not to reintroduce a national lockdown, is under increasing pressure.

He is expected to announce tougher measures — possibly including school closures — later Wednesday.

In Paris, intensive care beds are running low and infection rates are approaching last year’s peak, pushing medics to breaking point.

Australia, largely free of Covid infections, still faces a huge challenge to get jabs into arms, especially since some countries have started blocking exports to what they regard as a low-risk region.

So far, just 670,000 doses have been administered, well below initial plans to vaccinate four million people by the end of March.