Beijing's plans to develop an integrated online health platform featuring the digital health records of every resident has sparked concerns about intensified state surveillance.
China's National Health Commission announced last week that each resident would be given a "fully functional digital health code".
It's part of a five-year National Health Informatisation Plan to "digitise national health information" by 2025.
The announcement triggered a surge of interest on Chinese social media with a related hashtag about living with digital health codes post-Covid quickly receiving more than 38 million views on China's version of Twitter, Weibo.
Covid-19 health codes have been a core element of China's hardline health strategy during the pandemic.
For the past two years, a green health code has been required for entry to almost every public place in urban China - from supermarkets to restaurants, public transport and even parks - and also for travel between localities.
However, there have been instances where the system appears to have been abused to limit people's movement for non-health-related reasons.
And experts worry that Beijing will use an expanded health code system to even more closely surveil and control the populace.
How does China's Covid-19 health code system work?
The Covid-19 health codes work through mobile phone apps such as WeChat or Alipay, which are ubiquitous in China.
The apps track people's movements as users check in at locations and update users' status if they have visited a Covid "hotspot" or tested positive to coronavirus.
The app then displays their status as either green, yellow or red.
A red code means the person needs to be quarantined in a medical facility, while a yellow code indicates they should quarantine at home.
It's not a centralised national system but instead managed on a provincial level, with some variation between areas.
In megacities like Beijing, for example, a user's health code will turn grey if they fail to get tested when required, leaving them barred from entering most public places.
Often travellers will have to use several health codes issued by different local governments during their journeys.
'It's all automated and real time'
In Australia, the federal and state governments developed their own Covid tracking and check-in apps.
Meanwhile, Beijing turned to big tech companies Tencent and Alibaba to build the health code system into their apps WeChat and Alipay, which were already used for everything from chatting to paying bills.
Wilfred Wang, a media and communication lecturer at the University of Melbourne, has been watching China's implementation of the health code system closely.
Dr Wang said that even if people skipped scanning a code or two, their locations were still tracked.
"When you use the embedded programs on WeChat or Alipay, you are actually linking the health code to your social media accounts," Dr Wang said.
"Many people might have witnessed their health code turn yellow or red all of a sudden, even though they didn't declare they've been to any hotspots.
"It's all automated and real time."
What do we know about the expanded system?
While details about Beijing's plans are limited, according to the announcement: "Each resident will have a dynamically managed digital health record and a full-featured electronic health code."
A source "close to the NHC" told Chinese news website Caixin the new electronic health code would be different to the digital QR codes that track people's Covid test records and movements.
"[These two] are not the same thing," they said.
According to Caixin, the new health codes would be created based on residents' identification numbers.
Peking University health expert Li Ling told Chinese state media The Paper the digital health code was intended to improve medical services and people's lives.
"This is a very meaningful thing, to open and merge medical databases, and achieve interconnection and sharing of 1.4 billion people's health information," he said.
However, Deakin University media researcher Yang Fan said that despite claims of good intentions, the plan would not make accessing proper health care easier for the elderly or people lacking digital literacy.
Dr Yang said the Covid-19 health code was originally intended just to monitor users' health status to identify whether they were eligible to work.
But the announcement suggested that more sensitive health-related data would be collected and managed by the centralised system in the name of improving efficiency, she said.
Dr Wang said data collected recently from rural Hunan province showed that many people were not actively using the COVID health codes, because either they didn't have mobile phones or access to the internet.
"The usage rate in some areas is extremely low," he said.
He said Beijing might want to use the expanded health code system to put those people under surveillance too.
Potential for abuse
In June, customers of a rural bank in China's Henan province found their Covid-19 QR code unexpectedly turned red as they were on their way to the bank's headquarters to petition and demand their accounts be unfrozen.
Ausma Bernot, a PhD candidate at the School of Criminology and Criminal Justice at Griffith University, said the health code system was "an excellent means of keeping tabs on the population".
"There is a definite possibility that the health code might be integrated into broader structures of governance," she said.
However, Ms Bernot pointed out that people were outraged in early 2020 when a local government in China's Hangzhou city told its residents they were planning to make a version of the health code permanent.
Ms Bernot said the system had made the state's data harvesting and analysis more obvious than ever and pushback from the populace could stop the health code system from going beyond its original purpose.
The problem, she said, was that when a system of surveillance was well established, it was easy for the party-state to covertly extend the uses of that system.
China's National Health Commission has been contacted for comment.