China has administered 808.96 million doses of Covid-19 vaccines across the country, its National Health Commission (NHC) said on Wednesday.

This is up from just over 4.6 million doses daily at the end of April, and 661.47 million doses at the end of May. This means about 18.43 million doses were administered daily in the past week alone.

Beijing has set a target for 40 per cent of the population to be fully vaccinated by the end of June, and more than 80 per cent by the end of the year.

China has been marshalling state and party resources to boost the country's vaccination rate, which was off to a slow start.

In a way, its success in controlling the spread of the virus has also hampered its vaccine roll-out, with many people saying they did not feel there was a need to get vaccinated.

But minds have changed with the virus outbreaks in Liaoning province last month, and an ongoing spike of cases in Guangdong province, which is battling the Delta strain of the virus first detected in India.

A doctor from a community hospital in neighbouring Shenzhen city told The Straits Times that because of the outbreak, people have been "actively coming forward to get vaccinated".

But even as the pace of vaccination picks up, China faces several challenges.

Vaccination rates are much higher in cities than in urban areas, and could lead to an urban-rural vaccination divide. For instance, the Chinese capital of Beijing has fully vaccinated over 76 per cent of its population as at the start of this week, the Beijing Daily reported on Tuesday.

Contrast this with landlocked Jiangxi province, which has a population of 45.18 million, and has only vaccinated about a third of its people (15.56 million), according to data from the provincial government released last week.

The government has, however, set up rural vaccination centres to make it easier for villagers to get their jabs.

The biggest challenge China faces is the low efficacy rates of its vaccines compared with Western alternatives produced by Pfizer and Moderna, which have efficacy rates in excess of 90 per cent, said virologist Jin Dong-Yan from the University of Hong Kong.

China has approved seven domestically developed vaccines.

Efficacy data is available only for two vaccines by Sinopharm, and those from CanSino and Sinovac. Their efficacy rates range from 50.7 per cent to 79 per cent against symptomatic disease.

Prof Jin said low efficacy rates make it difficult to achieve herd immunity, meaning the virus would still be able to spread among vaccinated individuals.

"From the viewpoint of controlling the pandemic, it will mean that social distancing measures could never be relaxed," he said.

Still, China's inactivated virus vaccines have advantages, said Prof Jin.

"For example, you can use it in immunocompromised people, but for the general population it is still much, much less effective than the mRNA vaccines."

Beijing has seemed to acknowledge that its vaccines were lagging behind in terms of efficacy. Chinese Centre of Disease Control director Gao Fu said in April that "current vaccines don't have very high protection rates".

He later walked back on those comments, but his colleague Shao Yiming told Chinese media this week that the protection China's vaccines offer at the moment are aimed at "preventing symptomatic disease, and not to prevent transmission" of the virus.

Some netizens have expressed their desire to get vaccinated by Pfizer and BioNTech's mRNA vaccine on social media platform Weibo. For now, though, only domestically developed vaccines are available to the Chinese.

BioNTech and Chinese firm Fosun Pharma have set up a joint venture to manufacture the mRNA shot in China, although the shot has yet to be approved by the Chinese government.

Beijing office worker Nie Yanjie, who got her first dose of the Sinovac vaccine yesterday, said: "For regular people like me, it's hard to evaluate whether foreign or domestic vaccines are better. It's better to just listen to the government."