China's "Health Code" app, that tracks the movements and immune status of COVID-19 cases and contacts, is reaping unprecedented amounts of data on the country's population, including residents of Hong Kong and Macau.
Everyone in China has to download it, and is allocated a traffic-light health code of either green, amber or red. The algorithms that calculate this code are shrouded in secrecy, however, with people left guessing which information it uses based on real-world experiences.
There are signs of widespread "mission creep" from the app, as complaints grow among users of Chinese social media platforms that their health code has changed from green to amber after they bought over-the-counter cold remedies or pain relief medication, forcing them to take a COVID-19 test before being able to leave home.
A former contact tracing official surnamed Ma said the government is making use of "big data" on people's shopping habits and movements to try to preempt outbreaks of COVID-19.
"This big dataset can run through everything including your bank account," Ma told RFA. "It was initially put to use by the state security police, and was used in the past to investigate corrupt officials."
"It's now being used for epidemic prevention and epidemiological investigation to identify suspected spreaders [of COVID-19]," she said. "It has now been linked in to online merchants like Taobao, and will community pharmacies and neighborhood committees."
This means that seemingly straightforward transactions like the purchase of cold remedies or painkillers will be uploaded to the database, triggering an alert.
"The database alerts the police, and within five minutes of your buying that medicine, your local neighborhood committee will know, regardless of whether you bought it online on in a street store," Ma said.
"Some residential committees will call you, while others will just change your health code from green to amber," she said. "That means you won't be able to go anywhere, and you will have to self-isolate."
A Beijing resident surnamed Liu said she had been through something similar.
"If you have a sore throat or hoarseness and you go and buy medicine for it, you'll be told to do a COVID-19 test," Liu told RFA. "They wouldn't sell me painkillers when I went for my headache."
According to a Jan. 24 report in the China News Weekly, the massive datasets available to the authorities are regarded as a "sharp weapon" in the battle to enforce the ruling Chinese Communist Party (CCP)'s zero-COVID policy.
Less likely to seek treatment
According to Ma, this means that people are less and less likely to go to hospital or seek medical treatment for illness, as the health code system means they will need to wait around for 3-5 hours to get the results of a COVID-19 test before they can been seen by a doctor.
"That's not something people who are sick are going to find acceptable," she said.
The authorities have also tightened up inspections of in-bound parcels and packages, to stop people from buying over-the-counter remedies from overseas sites.
According to the China News Weekly, the use of big data is now a national strategy, and the health codes have been rolled out via eight nodes located in Guizhou, Gansu, Inner Mongolia, Ningxia, Beijing-Tianjin-Hebei, the Yangtze River delta, Chengdu-Chongqing and Guangdong-Hong Kong-Macau.
Current affairs commentator Wang Zheng said China's big data is also now combined with the Skynet video surveillance system to track the population's movements, contacts and transactions across the country.
"They record everything, including your consumption habits, including time, location and approximate amount, which exposes your habits," Wang said. "That includes your use of navigation software like Gaode and Baidu."
"For example, if I am navigating from Shijingshan in Beijing to Tongzhou, it would be quickest to go along Chang'an Avenue, but if a leader's car drives out of Xinhuamen in Zhongnanhai, big data can change the route by marking it as a traffic jam, and reroute you onto the Fourth Ring Road," Wang said.
Translated and edited by Luisetta Mudie.