The rapid and efficient strategy for SARS-CoV-2 Omicron transmission control: analysis of outbreaks at the city level

Zheng, Jinxin; Lv, Shan; Tian, Li-Guang; Guo, Zhaoyu; Zheng, Peiyong; Chen, Yuelai; Guan, Shi-Yang; Wang, Weiming; Zhang, Shunxian

doi:10.1186/s40249-022-01043-2

Cited by 11 publications

(6 citation statements)

References 52 publications

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“…In this study, we described and compared the epidemiological characteristics of outbreaks, caused by the Delta variant in 2021 and Omicron subvariants in summer 2022 in mainland China. We observed that Omicron subvariants spread more widely than Delta subvariants to all provinces in China, resulting in substantially higher case numbers in each outbreak and prolonged outbreaks [ 17 ]. The Omicron outbreaks in summer 2022 could not be controlled as effectively as for Delta [ 18 ] even with more intensive control measures corresponding to more substantial reductions in population mobility and higher vaccine coverage.…”

Section: Discussionmentioning

confidence: 99%

Comparative epidemiology of outbreaks caused by SARS-CoV-2 Delta and Omicron variants in China

Peng,

Huang,

Wang

et al. 2024

Epidemiol. Infect.

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From 2020 to December 2022, China implemented strict measures to contain the spread of severe acute respiratory syndrome coronavirus 2. However, despite these efforts, sustained outbreaks of the Omicron variants occurred in 2022. We extracted COVID-19 case numbers from May 2021 to October 2022 to identify outbreaks of the Delta and Omicron variants in all provinces of mainland China. We found that omicron outbreaks were more frequent (4.3 vs. 1.6 outbreaks per month) and longer-lasting (mean duration: 13 vs. 4 weeks per outbreak) than Delta outbreaks, resulting in a total of 865,100 cases, of which 85% were asymptomatic. Despite the average Government Response Index being 12% higher (95% confidence interval (CI): 9%, 15%) in Omicron outbreaks, the average daily effective reproduction number (Rt) was 0.45 higher (95% CI: 0.38, 0.52, p < 0.001) than in Delta outbreaks. Omicron outbreaks were suppressed in 32 days on average (95% CI: 26, 39), which was substantially longer than Delta outbreaks (14 days; 95% CI: 11, 19; p = 0.004). We concluded that control measures effective against Delta could not contain Omicron outbreaks in China. This highlights the need for continuous evaluation of new variants’ epidemiology to inform COVID-19 response decisions.

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Section: Discussionmentioning

confidence: 99%

Comparative epidemiology of outbreaks caused by SARS-CoV-2 Delta and Omicron variants in China

Peng,

Huang,

Wang

et al. 2024

Epidemiol. Infect.

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“…In addition, it has also shown that as long as NPIs are strong enough, that is, the diagnostic rate and isolation rate are both high, then the government’s response time is much less sensitive to outbreaks. This indicates that strong control efforts have quite significant inhibitory effects on the spread of COVID-19 [ 55 ]. Under the same conditions, social activity control can be dynamically adjusted according to the daily number of reported cases to keep the outbreak at a low level.…”

Section: Discussionmentioning

confidence: 99%

Lessons drawn from Shanghai for controlling highly transmissible SARS-CoV-2 variants: insights from a modelling study

Wang

Gao

et al. 2023

BMC Infect Dis

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Background The continuous emergence of novel SARS-CoV-2 variants with markedly increased transmissibility presents major challenges to the zero-COVID policy in China. It is critical to adjust aspects of the policy about non-pharmaceutical interventions (NPIs) by searching for and implementing more effective ways. We use a mathematical model to mimic the epidemic pattern of the Omicron variant in Shanghai to quantitatively show the control challenges and investigate the feasibility of different control patterns in avoiding other epidemic waves. Methods We initially construct a dynamic model with a core step-by-step release strategy to reveal its role in controlling the spread of COVID-19, including the city-based pattern and the district-based pattern. We used the least squares method and real reported case data to fit the model for Shanghai and its 16 districts, respectively. Optimal control theory was utilized to explore the quantitative and optimal solutions of the time-varying control strength (i.e., contact rate) to suppress the highly transmissible SARS-CoV-2 variants. Results The necessary period for reaching the zero-COVID goal can be nearly 4 months, and the final epidemic size was 629,625 (95%CI: [608,049, 651,201]). By adopting the city-based pattern, 7 out of 16 strategies released the NPIs more or earlier than the baseline and ensured a zero-resurgence risk at the average cost of 10 to 129 more cases in June. By adopting the district-based pattern, a regional linked release can allow resumption of social activity to ~ 100% in the boundary-region group about 14 days earlier and allow people to flow between different districts without causing infection resurgence. Optimal solutions of the contact rate were obtained with various testing intensities, and higher diagnosis rate correlated with higher optimal contact rate while the number of daily reported cases remained almost unchanged. Conclusions Shanghai could have been bolder and more flexible in unleashing social activity than they did. The boundary-region group should be relaxed earlier and more attention should be paid to the centre-region group. With a more intensive testing strategy, people could return to normal life as much as possible but still ensure the epidemic was maintained at a relatively low level.

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“…It is challenging to strike a balance between epidemic prevention and control and economic and social development. Each country and city may have its own unique circumstances that require additional considerations and adaptations [ 1 ]. China has a population of 1.41 billion.…”

Section: Reopening Policymentioning

confidence: 99%

The COVID-19 pandemic in China: from dynamic zero-COVID to current policy

2023

Herz

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On 8 January 2023, after 3 years of pandemic control, China changed its management of COVID-19, applying measures against class B infectious diseases instead of Class A infectious diseases. This signaled the end of the dynamic zero-COVID policy and the reopening of the country. With a population of 1.41 billion, China’s reopening policy during the COVID-19 pandemic has been characterized by a scientific, gradual, and cautious approach. Several factors contributed to the reopening policy, including an expansion of healthcare capacity, the widespread promotion and uptake of vaccination, and improved prevention and control mechanisms. According to the latest report from the Chinese Center for Disease Control and Prevention, the number of hospitalized COVID-19 patients in the country reached a peak of 1.625 million on January 5, 2023, and has since continued to decline. As of February 13, the number decreased to 26,000: a reduction of 98.4%. Thanks to the efforts of healthcare workers and society as a whole, the country managed to get through the peak of the epidemic in a stable manner.

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The rapid and efficient strategy for SARS-CoV-2 Omicron transmission control: analysis of outbreaks at the city level

Cited by 11 publications

References 52 publications

Comparative epidemiology of outbreaks caused by SARS-CoV-2 Delta and Omicron variants in China

Comparative epidemiology of outbreaks caused by SARS-CoV-2 Delta and Omicron variants in China

Lessons drawn from Shanghai for controlling highly transmissible SARS-CoV-2 variants: insights from a modelling study

The COVID-19 pandemic in China: from dynamic zero-COVID to current policy

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