China raced to vaccinate its most vulnerable people on Thursday in anticipation of waves of Covid-19 infections, with some analysts expecting the death toll to soar after it eased strict controls that had kept the pandemic at bay for three years.

The push comes as the World Health Organisation also raised concerns that China's 1.4 billion population was not adequately vaccinated and the United States offered help in dealing with a surge in infections.

Beijing last Wednesday began dismantling its tough ‘zero-Covid’ controls, dropping testing requirements and easing quarantine rules that had caused anxiety for tens of millions and battered the world's second-largest economy.

The pivot away from President Xi Jinping’s signature “zero-Covid” policy followed unprecedented widespread protests against it. But, WHO emergencies director Mike Ryan said infections were exploding in China well before the government's decision to phase out its stringent regime.

“There’s a narrative at the moment that China lifted the restrictions and all of a sudden the disease is out of control,” Ryan told a briefing in Geneva.

“The disease was spreading intensively because I believe the control measures in themselves were not stopping the disease.”

Chinese foreign ministry spokesperson Wang Wenbin said on Thursday China has “institutional advantages” to fight Covid.

“We will certainly be able to smoothly get through the peak of the epidemic,” he told a regular news briefing in response to White House national security spokesperson John Kirby saying that the United States was ready to help if China requested it.

There are increasing signs of chaos during China’s change of tack - including long queues outside fever clinics, runs on medicines and panic buying across the country.

On Thursday night, China’s state asset regulator urged state-backed big drugmakers to ensure supplies of Covid-related medicines.

The companies include China Resources, China General Technology and Sinopharm, which own businesses that produce drugs that could ease coronavirus symptoms.

One video posted online on Wednesday showed several people in thick winter clothes hooked up to intravenous drips as they sat on stools on the street outside a clinic in central Hubei province. Reuters verified the location of the video.

The Covid scare in China also led people in Hong Kong, Macau and in some neighbourhoods in Australia to go in search for fever medicines and test kits for family and friends on the mainland.

For all its efforts to quell the virus since it erupted in the central city of Wuhan in late 2019, China may now pay a price for shielding a population that lacks “herd immunity” and has low vaccination rates among the elderly, analysts said.

“Authorities have let cases in Beijing and other cities spread to the point where resuming restrictions, testing and tracing would be largely ineffective in bringing outbreaks under control,” analysts at Eurasia Group said in a note on Thursday.

“Upward of 1 million people could die from Covid in the coming months.”

Other experts have put the potential toll at more than 2 million. China has reported just 5,235 Covid-related deaths so far, extremely low by global standards.

China’s stock markets and its currency fell on Thursday on concerns of the virus spread.

China reported 2,000 new symptomatic Covid-19 infections for Dec. 14 compared with 2,291 a day. The official figures, however, have become less reliable as testing has dropped. It also stopped reporting asymptomatic figures on Wednesday.