A campaign to vaccinate the elderly has sparked hopes China might roll back severe anti-virus controls that prompted protesters to demand President Xi Jinping resign, but the country faces daunting hurdles and up to a year of hard work before “zero COVID” can end.

Stock markets rose after the National Health Commission on Monday announced the long-awaited campaign. A low vaccination rate is one of the biggest obstacles to ending curbs that have confined millions of people to their homes, depressed the economy and kept most visitors out of China. Health officials gave no indication how long it might take.

A vaccination campaign will require months and China also needs to build up its hospitals and work out a long-term virus strategy, health experts and economists warn. They say “zero COVID” is likely to stay in place until mid-2023 and possibly as late as 2024.

“China is in no place right now to move away from its ‘zero-COVID’ policy toward a ‘living with COVID’ policy,” said Mark Williams, chief Asia economist for Capital Economics. “Health care capacity is very weak.”

China, where the virus first was detected in late 2019 in the central city of Wuhan, is the last major country trying to stop transmission completely. Others are relaxing controls and trying to live with the virus that has killed at least 6.6 million people worldwide and sickened almost 650 million.