Health workers line up to spray disinfectant at Wuhan Railway Station on March 24, the day officials announced when Wuhan's lockdown would end Getty Images / STR / Contributor

Though restaurants have reopened, Wang Lan, who works for a Wuhan-based media company, hasn’t eaten out since the city’s 76-day lockdown was lifted on April 8. “People generally choose to get food delivered,” she says. Back when the epidemic was at its worst, only one person from each family was allowed to leave the apartment compound, for a two-hour window, to buy groceries.

Wang worked from home for two months, returning to the office in April. Her company organised testing for the whole staff and implemented new rules. With more than 1,000 employees, before the outbreak you could go to the cafeteria buffet, but now lunch is packed for each person and employees go in shifts to collect their lunch, then eat it separately. Wang still avoids going to places with a lot of people and continues minimising time at the supermarket.


When she arrives or leaves her office, she scans her “health code” – accessible through Alipay and WeChat. Her code is green, meaning she is allowed to travel domestically. Those with yellow or red codes have to stay at home. The codes have become crucial to everyday life. She scans it to get onto public transport, to go to the supermarket, and to enter and leave her residential compound.

However, the name “health code” is somewhat misleading. The closest thing to the colour-coded health codes being used in China are immunity certificates Western countries are discussing. While a green code allows you to travel, it does not mean you are immune from coronavirus. It is a “probably not infected” pass for those that want to get back to work.

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While local governments have each launched their own health code mini-programs, the interface is the same for the user. In essence, departments have integrated data on travel (from bus, train, and flight bookings), contact with known, suspected or confirmed cases, and self-reported symptoms to generate the traffic light colours – red, yellow or green – which indicates how high-risk the individual may be.

In Wuhan, it takes into account hospital-visit data. At the end of February, Li Jiaying’s mother went to the hospital for a check-up, fearing she had the virus. Though a doctor found her virus-free, Li’s mother found her health code went red soon after she returned home – probably because hospitals were high-risk areas for transmission. She had to stay inside for the next 14 days (during this time, codes of family members she was living with remained green).


Almost two months later, most people Li knows, herself included, have a green code. For inter-city travel, residents of Hubei reported that while a green code was enough to leave the province, they still had to undertake quarantine or testing once they arrived. They also obtained approval from the neighbourhood Party committee that managed the address to which they planned to move. Universities that have yet to open their doors have ordered students currently in Hubei not to come back until they give notice.

During the epidemic’s peak, students started reporting their health status on platforms they usually used to check in for lectures. Li saw that her name was in red on her teacher’s interface, a visual note for the university’s Party secretary and counsellors to personally check on her health status, which she still submits digitally everyday.

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Nationally, many employees self-reported their health status, answering single-choice questions on whether they had coronavirus symptoms, their current location, and whether they had been to, or had any contact with people from Hubei. That data was filed to local governments to establish which employees were allowed to return to their offices.


The anonymised location and movements of confirmed new cases continue to be posted on trackers embedded into popular apps such as Toutiao and Baidu. As Chinese nationals continue to return from outside the country, many of the latest updates are of new cases flying into airports who are sent straight into mandatory quarantine, which returnees have to pay for. The last few confirmed cases for Shanghai, at time of writing, were students returning from the UK.

A month or so before, these maps were more dynamic. Citizens could see just how far they were from confirmed cases, how many cases each district had, and whether people in their apartment buildings had been infected. They could also check whether they had taken transport with someone who tested positive.

Telecom providers have been involved in public health messaging. They have pushed lengthy SMS messages to Wuhan residents on how to troubleshoot problems with the health code. They have also sent advice signed off by the city’s prevention and control department on mask-wearing, hand hygiene, and using contactless payments where possible. Local governments have tacitly admitted the system has teething problems by instituting channels for people to apply to have their colour changed to green, if they think they have been wrongly assigned yellow or red.

Coronavirus–related tech experiments in Europe are having their own issues. Researchers are torn over how to implement privacy protecting contact tracing. A report on one such app under development in Germany, found it could “only be installed on up-to-date Apple and Android phones, which will reduce its coverage to roughly 60-65 per cent of the general population,” says Sven Herpig, director for international cybersecurity policy at Berlin-based thinktank SNV. People may not want to be part of these infrastructures, or not have the means to join. If apps don’t work and scale, at some point we may have to decide to go non-digital.

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None of the apps rolled out in China are replacements for traditional epidemic-fighting strategies such as human-led contact tracing – identifying those who fall ill, finding those with whom they have recently been in contact, and quarantining them. Despite the attention given to the health code, the country’s virus mitigation strategies are rooted in boots-on-the-ground management. Tech experiments have been layered over other epidemic-fighting infrastructure, so judging their utility is difficult. Often left out of the conversation is at what point tech applications become useful, and when they are no longer. “We don’t have proof that any of it really worked,” Herpig says.

China’s health code is not the precise contact tracing that Apple and Google want to roll out. In fact, it is surprisingly low-tech. That its initial questionnaire includes whether you have had contact with people from Hubei shows that the authorities managing the app don’t know. Workarounds for Wuhan’s grey-haired residents are even more low-tech. Li’s grandparents who don’t own smartphones use health certificates issued by their community as a health code substitute. Other neighbourhood committees have their non-smartphone residents print out a paper-version of the health code.

The health code is far from a silver bullet. Ultimately, what generates a green code is the commitment of individuals to stay at home for 14 days, and residential committees, which manage apartment compounds, to manage their designated inhabitants. But even as a pass to help with reopening, it has returned many to some level of normalcy.

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