The Beijing Health Commission announced that from next week anyone entering libraries, museums, cinemas, art galleries, sports and fitness venues, entertainment venues or any crowded places in the capital "must be vaccinated".

China has so far resisted mass vaccine mandates as part of its pursuit of "zero-COVID", instead relying on strict lockdowns, contact tracing, automatically tracking people's travel history and mass PCR testing to try to stamp out outbreaks as they arise.

However, employees working in "high-risk" sectors, including public transport, have previously been required to have been vaccinated.

The mandate seems to represent a sharp change in policy.

In July last year, China Daily, a Communist Party-controlled newspaper, said: "Vaccination must be voluntary not compulsory."

Both Beijing and Shanghai seemed to have controlled outbreaks of the Omicron variant in recent weeks and months.

In Shanghai's case, this necessitated a severe, months-long lockdown, with people confined to their homes and relying on the government to deliver groceries.

However, other big cities are struggling with mounting cases, with cases surging in the eastern province of Anhui, near Shanghai. Xi'an, the capital of Shaanxi province, announced lockdown measures after detecting 18 new cases.

Those cases were of the Omicron BA.5 variant, rather than the BA.2.2 variant which was responsible for the recent Shanghai and Beijing outbreaks.

"The Omicron BA.5 subvariant is even more transmissible and spreads more quickly than the previous BA2.2 sublineage, and it is more likely to escape antibodies," Zhang Yi, from the centre for disease control and prevention in Shaanxi, said on Tuesday.

The BA.5 variant is now the dominant strain in the US and appears to be driving a new wave of infections in the UK too.

The variant has also been detected in Beijing over the last two days. Six new cases were reported in the last 24-hour period. It is unknown whether the new government vaccine mandate was in connection with that.

'Disappointed and angry'

There was a negative initial reaction online to the announcement, with one Weibo user saying: "According to Chinese law, the vaccination should be not forced."

Another posted: "Disappointed and angry at the Beijing vaccine policy."

Beijing said it had fully vaccinated 97.7% of its residents as of last September but reported in April that nearly 20% of residents over 60 years old had not yet had a first dose, according to Reuters.

Overall, the number of new infections in China remains extremely low compared with other countries, with 353 cases reported on Wednesday.

Although the government has announced some relaxation in COVID-zero measures, shortening quarantine times for international travellers and easing internal travel restrictions, it shows no sign of abandoning the policy.

President Xi Jinping has said that "persistence is victory" in controlling the epidemic.

The World Health Organisation has previously said that China's zero-COVID strategy is not sustainable.