More than 1.3mn people in China were under medical observation this week as close contacts of cases of Covid-19, the highest level since the pandemic erupted out of Wuhan, and an increase of more than 300,000 in just a few days.
The soaring number of close contacts, driven by a rise in cases to near record levels, is putting immense strain on a Covid-19 policy that in contrast with the rest of the world aims to eliminate rather than live with the virus.
China’s strategy has evolved since the start of the pandemic. While authorities have often relied on citywide lockdowns, most notably in Wuhan in early 2020 and in Shanghai in 2022, they also use a sophisticated track and trace system that quickly quarantines close contacts of infections for “medical observation”.
The total number of close contacts is an important gauge of whether authorities are still able to control the virus in China. Meanwhile, evidence from Guangzhou, the centre of the latest outbreak, indicates a gap between the official guidance and reality.
How are close contacts traced?
In big Chinese cities, residents must take a PCR test every few days at booths set up on street corners to obtain a “green code” on their smartphones. Their phone also needs to be scanned on most public transport and when entering buildings.
If a person tests positive, authorities can analyse the locations the person has visited to trace who else scanned there. Close contacts can also be determined based on a person’s residence or place of work.
What happens to close contacts?
This month, amid rising cases, the government tweaked the approach it set out in June when it published the ninth edition of its Covid-19 strategy.
Under the revised guidance, close contacts should be taken to a “centralised isolation place”, often a hotel, where they must remain for five days, down from the previous seven. This is to be followed by a further three days of observation at home.
Local governments have invested in building temporary isolation facilities. In October, Shanghai confirmed it would build a 3,000-person facility on Fuxing Island at a cost of about $220mn, designed for both close contacts and positive cases.
A construction bidding website reveals dozens of other similar projects across China in recent months.
However, government guidance also states that “special” cases may be allowed to isolate at home. It does not clearly define a special case, although individual provinces have their own interpretations. In Hebei, children 14 and younger are treated as special cases.
What is the reality on the ground?
When asked how many of the more than 1mn close contacts under medical observation were quarantined at central facilities compared with at home, China’s National Health Commission directed the inquiry to the Centre for Disease Control and Prevention, which could not be contacted.
The central guidance may be applied differently in different provinces. The example in Guangzhou, where daily cases are in the thousands, indicates authorities are struggling to find capacity to meet the central quarantine requirement. One resident, who asked to be referred to as Victor, said his family were designated close contacts after dining at a restaurant where there was a confirmed positive case.

He said his family was told to prepare for a quarantine hotel but was later informed there was not enough space there and that new quarantine sites had not been built yet. Instead, his door was sealed and he and his family isolated at home.
Elsewhere there is flexibility in the definition of a close contact. If there is a positive case in a building in Beijing, authorities designate the three floors above and below the case as close contacts and send those residents to central quarantine. Other floors are required to quarantine at home.
When a single positive case was detected at Disneyland Shanghai this month, authorities locked down the park and tested tens of thousands of people, but did not define guests as close contacts. However, some Disneyland staff were designated close contacts and sent to central isolation facilities.
What happens next?
A requirement to quarantine close contacts of close contacts was relaxed this month. But expectations of a reopening have been downplayed after the city of Shijiazhuang, which had relaxed testing during its outbreak, reinstated stricter measures.
If the number of close contacts spirals further out of control, the government could enforce much harsher lockdowns, as in Shanghai this spring. Such a decision might be taken centrally, but it would still need to be enforced by multiple local governments and cities.
Even if the virus can no longer be controlled, any shift from a model of elimination to one based on suppression is unlikely to be straightforward. Instead, there are signs that elements of the former would probably persist.
One person who works in labour outsourcing in Guangzhou, which recorded nearly 8,000 cases on Wednesday, said the city was hiring dozens of drivers to transfer close contacts to quarantine hotels to deal with the rising number of contacts.
Additional reporting by Ryan McMorrow in Beijing and Gloria Li in Hong Kong