Monday, May 02, 2022

China CDC Weekly Commentary: Persevere in the Dynamic COVID-Zero Strategy in China



Given its extreme (and apparently growing) transmissibility, the Omicron variants emerging around the globe (BA.2, BA.2.12.1, BA.4, BA.5, etc) appear unstoppable, even with vaccines, social distancing, and other NPI (non-pharmaceutical intervention) measures. 

Their impact, luckily, has been  blunted by a high vaccine uptake, and therefore we've seen relatively low numbers of severe illness (compared to Delta). 

But in some places - like Hong Kong - where vaccine (and booster) uptake has been low, particularly among the elderly, we've seen significant mortality (see MMWR report (COVID-19 Mortality and Vaccine Coverage — Hong Kong Special Administrative Region, China, January 6, 2022–March 21, 2022)).

While most countries around the world have dropped or relaxed their pandemic restrictions due to the futility of trying to contain the virus, Mainland China continues to espouse and practice a `Zero-COVID' policy.  

Shanghai - China's most populous city - has remained largely under lockdown for over a month, as have many other cities, affecting tens of millions of people (see NPR's 45 cities in China are in some sort of COVID lockdown). 

Beijing and Guangzhou both appear on the verge of going into a Shanghai-style lockdown, as President Xi doubles down on their Zero-COVID strategy, despite the enormous economic and societal costs involved.

Shanghai is reporting fewer cases in recent days, and short-term victories against the virus may be achievable, but it is far from clear how China can deal with the near-constant reintroduction of new variants from outside of their country. 

Although it may appear to be a Sisyphean task to the rest of the world, China's willingness to go to extremes to prevent the spread of COVID apparently makes sense to them.  

While it doesn't address the long-term challenges, China's CDC Weekly (a clone of our MMWR) has a commentary this week by Dr Liang Wannian et al. on their rationale behind pursuing a Zero-COVID policy.

First the commentary, then I'll return with a brief postscript. 

Persevere in the Dynamic COVID-Zero Strategy in China to Gain a Precious Time Window for the Future

Jue Liu1; Min Liu1, , ; Wannian Liang

According to the report of World Health Organization (WHO), as of April 20, 2022, the cumulative number of confirmed cases of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the world had exceeded 500 million, with 6.20 million deaths and over 580,000 new confirmed cases on that day (1). As many countries have announced to relax quarantine policies, China is facing increasing pressure from overseas imports. All 31 provincial-level administrative divisions (PLADs) of China have reported a total of 191,112 local confirmed cases, with 2,761 new confirmed cases, 17,166 new asymptomatic infections, and 7 new deaths (all in Shanghai Municipality) on April 19 (2). Recently, several local outbreaks in clusters have appeared in China, presenting a grim and complex situation with multiple spots, wide coverage, and frequent occurrence (3).

Omicron Spreads Quickly and Is Harmful to Those at Risk

The current epidemic was mainly caused by Omicron variant BA.2, which has a short incubation period, strong transmissibility, short serial interval, and a large ability of immune escape (4-5). It was found that the basic regeneration number (R0) of Omicron variant was about 9.5, and its maximum incubation period was about 9 days (4-5). The median incubation period was about 3 days, which was significantly shorter than that of the Delta variant (4.3 days) and other variants (5.0 days) (4-5). Its median serial interval was about 2.8 days (4-5).

It is reported that the proportion of asymptomatic infections of Omicron variant was relatively high (4). There are some reasons for this phenomenon. First, the characteristics of Omicron variant caused a higher proportion of asymptomatic infections than that of other variants. Second, some people did not develop symptoms even after being infected because of the coronavirus disease 2019 (COVID-19) vaccination. Third, early detection can find infections at early stages when symptoms had not yet appeared. In addition, the training of medical staff to improve their ability to correctly conduct diagnosis and treatment, scientifically and reasonably determinate the asymptomatic and confirmed cases, also needed to be strengthened.
According to the Statistics on the 5th Wave of COVID-19 in Hong Kong, the population-wide mortality rate caused by Omicron variant was 799 per million and for people over 80 years old was 10,408 per million ((6-7). According to the real-world data in Hong Kong, the fatality rate of the Omicron variant (0.76%) was significantly higher than that of influenza (0.1%), and it reached 10.4% among people over 80 years old (6-7). The elderly, people with underlying diseases, and those who have not been vaccinated were at high risk of severe illness and death. Of the 8,973 patients who died (0–112 years old) in Hong Kong, 96% were the elderly, and 88% were not fully vaccinated.
Fortunately, a large real-world study in Hong Kong showed that three doses of either vaccination against COVID-19 offered very high levels of protection against severe illness and death caused by the Omicron variant (vaccine effectiveness 98.1%, 95% confidence interval: 97.1%, 98.8%) (8). Although the total vaccine coverage in the mainland of China is high, compared with adults, the two-dose or booster vaccination rate of the elderly and children was relatively low. In Shanghai, for example, the two-dose vaccination rate for people over 80 years old is only about 15% (9). There are still a large proportion of susceptible people.

The Dynamic COVID-Zero Strategy Is Still Required

China should still persevere in the Dynamic COVID-Zero Strategy. Putting people’s lives and health first is the fundamental starting point and goal of all prevention and control measures in China. Because of the large population, unbalanced regional development, and insufficient total medical resources, China will face the risk of serious runs of medical and health resources if the “lying flat” strategy is adopted (10). The health of many patients with underlying diseases, the elderly, children, and pregnant women will be seriously threatened, and the steady economic and social development will be seriously affected (10).

Dynamic COVID-Zero Strategy is the general guideline for China’s fight against COVID-19, which is also a summary of previous experiences in fighting against dozens of domestic clusters of outbreaks since 2020. The multiple rounds of COVID-19 have proved that the Dynamic COVID-Zero Strategy is in line with China’s national conditions and is the best option for China to fight the epidemic, which is based on the concept of “people first, life first.” China has the capability, the foundation, the conditions, and the toolkits to implement this strategy. Also, China has strong institutional advantages, professional teams, and the support of the public, which will form the greatest protection for life.

The core of the dynamic zero strategy lies in early detection, rapid containment, and cutting off transmission to prevent continuous spread and large-scale rebound of the epidemic (11). This is not about “zero infection” or “zero tolerance” of COVID-19, but about science and precision. The premise of precision is to be effective. In the face of the virus, we need to stay ahead. Zero community transmission refers to newly discovered infected persons being comprehensively found in quarantined and controlled populations without the possibility of spreading to the rest of society. The temporary inconveniences in some areas is for longer-term normal life and socioeconomic development of the population more broadly. We need to take a systematic approach and a long-term view to do the best to strike a better balance between epidemic prevention and control with socioeconomic development.

Seize the Opportunities to Gain Precious Time Window for the Future

At present, China has entered the fourth stage of comprehensive epidemic prevention and control, namely, “scientific, accurate, and dynamic COVID-zero” (10). Facing the rapidly spreading Omicron, in order to stop the spread of the epidemic in the community as soon as possible, we are supposed to make coordinated efforts to control the outbreak at early stages, including control of at-risk populations, detection, epidemiological investigation, transport, isolation, treatment, and other aspects (10).
The Dynamic COVID-Zero Strategies adopted by China has won a precious time window for the future. China should seize this opportunity to speed up research and development of specific drugs and vaccines, accelerate the two or three-dose vaccination of the population, especially for the elderly and children, and strengthen the preparedness of resources for the future to finally defeat the virus at a minimal cost.

Given the lack of community immunity, and a less-than-robust Sinovac vaccinethe Omicron variant would likely find a target rich environment on the Mainland, and Chinese officials are probably right to fear  `. . . the risk of serious runs of medical and health resources if the “lying flat” strategy is adopted.'

With China set to hold their 20th CCP congress sometime in the `2nd half of the year' - and with President Xi determined to secure reelection as General Secretary of the CCP and President of the Republic - a high mortality wave of COVID this summer would be politically inconvenient.  

Of course, risking an economic collapse in pursuit of Zero-COVID wouldn't play out much better.  Particularly since - at best - China's COVID policies are only likely to delay the inevitable.  But that may simply be the plan.  

While this commentary suggests that Zero-COVID policies can give them precious time to `. . speed up research and development of specific drugs and vaccines, accelerate the two or three-dose vaccination of the population', it may also get them past a political hurdle as well. 

It may be that Chinese scientists are on the verge of developing a better, and more broadly protective, vaccine.  Or perhaps they believe COVID will `settle down' in the months ahead, into a less mutable virus.  

Of course,  they may simply be `stuck' with a policy they don't feel like they can change without losing credibility. 

Like the rest of the world, I'm mystified by China's policy.  But I have to assume they think their reasons are good enough to risk further economic and societal repercussions.  

And since China presumably knows more about the SARS-CoV-2 virus than anyone else in, I'd love to know what it is they think they know, that we apparently don't.