Surveillance of infection reproduction rate, R0, will be crucial for any decision to lift the lock. The figure shows how contagious an infection is. Like the R0 the number drops below one, each existing infection causes less than one new infection; eventually, the epidemic will decrease and end. When R0 regularly remains below one, governments may decide to gradually loosen restrictions, with the lock being relaxed earlier in low intensity areas and later in key cities like London.
New data published this week in The Lancet, by a team of researchers from the University of Hong Kong led by clinician Gabriel Leung, shows that the spread of infection in China outside Wuhan, as measured by the R0 in four major cities (Beijing, Shanghai, Shenzhen and Wenzhou) fell below one within two weeks of the partial foreclosure. It’s good news; it shows that a partial lock can quickly suppress the transmission of the virus. Our national locking and social distancing measures may already have0 in much of the country.
But the problem remains how to prevent a second push. Hong Kong researchers fear that as economic activity picks up, local and imported cases of coronavirus could lead to new epidemics. And the R0 the rate varies by region: case fatality rates were just below 1% in Beijing, Shanghai, Shenzhen and Wenzhou compared to 5.9% in Wuhan. We will also likely see a higher infection and death rate in London than in the rest of the UK.
In addition, there is a crucial difference between the response to the coronavirus in China and that in the United Kingdom. Since the start of the epidemic, Lancet researchers note that “only residents have been allowed to enter residential communities, the wearing of face masks has been made compulsory and non-essential community services have been closed.” Health authorities also found cases, found contacts and isolated them, closely monitoring their quarantine.
So it was not only social lock-in and distancing that were responsible for the0 in China, but the country’s community surveillance approach. Marked by memories of the Sars epidemic in 2002, China and other East Asian states acted more quickly, imposing total or partial locks supported by a protective shield from community measures – finding people infected, quickly isolating them and tracing those they contacted.
In South Korea, this has taken the form of mass testing and digital contact tracing; in Taiwan, Hong Kong and Vietnam, health officials have identified cases based on the symptoms of people and used tests when available. The strict isolation of cases and contacts was controlled by phone applications and home visits. Rather than applying a single approach, China has varied the lockout by region. While Wuhan was in a total lockdown, the other provinces had more autonomy and concentrated on quarantining the clusters of households where transmission took place most.
The data seems to show that this approach is the right one. Mortality rates in Asian countries have been lower than those in the United States and Europe (the death rate in South Korea, for example, is four per million and stable; that in the United Kingdom is 105 per million – and it increases). In addition to helping reduce R0 many, a community shield can also enable governments to remove national blockages more quickly. Rather than maintaining a prolonged foreclosure, governments can target measures on people who actually have a coronavirus. This would likely be much less disruptive to the economy: it is better to quarantine 10% of people with symptoms of coronavirus than an entire population.
At first, Britain abandoned the community shield approach. On March 12, the government stopped community testing and went into a “delay” phase, explaining that a managed spread of the virus in 60% of the population, with a fatality rate of about 1%, should, hopefully, produce collective immunity and allow the economy to move on. After its modellers realized that this strategy was going to overwhelm the NHS, the government imposed a lockdown. He is now trying to run 10,000 tests a day, mostly in hospitals for patients and health workers.
Despite Britain’s slow start, there is reason to hope. Behind the scenes, general practitioners and public health workers are working at incredible speed to build our own protective shield. They find places to care for infected patients who are not sick enough for the hospital but cannot be cared for at home, visit those who have long-term illnesses or have symptoms of coronavirus, and chart the community spread using 111 data. The UK is also expected to be able to deploy contact tracking using the new NHSX app and popular symptom tracker Zoe Covid.
We have four to six weeks to speed up testing and build our community shield before lifting the lock. After that, we can then put most people back to work, focus on quarantining individual cases and contacts, and suppress outbreaks if they occur. Hopefully this approach will help us avoid further national bottlenecks. But it will take a long time before life returns to normal.
• Anthony Costello is Professor of Global Health and Sustainable Development at University College London