How efficient was the Shanghai lockdown coverage in contrast with that of different nations?

The Omicron variant of the extreme acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus is many occasions extra contagious than earlier variants. Throughout the course of the coronavirus illness 2019 (COVID-19) pandemic, lockdowns have been applied globally to curb the unfold of the virus. Whether or not such lockdowns have been efficient or not stays unknown.

Study: The Effect of Strict Lockdown on Omicron SARS-CoV-2 Variant Transmission in Shanghai. Image Credit: Graeme Kennedy/Shutterstock
Research: The Effect of Strict Lockdown on Omicron SARS-CoV-2 Variant Transmission in Shanghai. Picture Credit score: Graeme Kennedy/Shutterstock

A latest research revealed in Vaccines aimed to fill this hole in analysis by evaluating the affect of strict lockdown measures on SARS-CoV-2 Omicron transmission in Shanghai between March and April 2022.


To curb the unfold of the SARS-CoV-2 virus, many nations have extensively deployed non-pharmaceutical interventions (NPIs) and lockdowns. Regardless of the event of vaccines, variants of concern (VOC), such because the Delta variant, have pushed massive and disruptive waves. The Omicron VOC was first recognized in South Africa in November 2021, with key mutations accountable for immune escape (K417N, E484A, and T478K).

The Omicron changed the Delta variant quickly because the dominantly circulating pressure, hinting at its robust selective benefit. In comparison with the Delta variant, Omicron has a higher affinity for human angiotensin-converting enzyme 2, and this is because of numerous mutations within the receptor-binding area (RBD).

The epidemiology of the early 2022 Hong Kong wave confirmed that the intrinsic severity of Omicron might be much like ancestral strains. Given the mutations within the Omicron variant, researchers might want to develop Omicron-specific vaccines, and within the meantime, lockdown measures should still be wanted to manage the viral unfold. However, the efficacy of lockdowns in curbing the unfold of the Omicron variant stays unknown.

In regards to the research

The present retrospective research analyzed the strictness of the lockdown coverage enacted in Shanghai and contrasted it with different nations. Particularly, the latest Omicron wave was thought-about by evaluating case numbers in March and April 2022, and significant components to make lockdowns efficient have been recognized. The efficacy of the lockdown was gauged by calculating the efficient reproductive quantity based mostly on the every day case numbers. Pearson correlation coefficients have been computed to focus on the driving components of strict lockdowns within the 16 totally different districts of Shanghai. 

Key findings

The correlation evaluation revealed that the well timed lockdown was instrumental in controlling the Omicron epidemic in city areas. The lockdown was applied proper earlier than the case numbers surged, which may have stopped the asymptomatic transmission. Per the present research, prior analysis has additionally utilized the identical Oxford Coronavirus Authorities Response Tracker challenge and studied the connection between social distancing measures and illness incidence in 149 nations. These research documented that early lockdown implementation was related to a higher decline within the incidence of COVID-19. Related outcomes have been documented within the present research within the context of the Omicron variant.

It was hypothesized that stopping neighborhood transmission by means of lockdowns in Shanghai may have mitigated the asymptomatic transmission amongst younger and middle-aged people. Insights from a earlier New Zealand research have been used to assist this speculation. New Zealand had a low proportion of asymptomatic an infection, regardless of widespread testing, in comparison with different nations. It was believed that the low degree of neighborhood transmission primarily drove this.

It was additionally highlighted that lockdown measures ought to be applied in another way amongst younger/middle-aged folks and the aged. It is because the previous group is extra cell and more likely to transmit an infection quicker. The present research attributed the post-lockdown low asymptomatic viral transmission in Shanghai to low and middle-aged people, whose actions have been restricted way more. 

Strengths and limitations

Most nations adopted looser public well being social measures in comparison with the strict lockdown in Shanghai. Coupled with the Omicron outbreak, this supplies a chance to precisely research the effectiveness of strict lockdowns in decreasing the transmission of the Omicron variant. The research’s essential limitation was the lack to measure inhabitants mobility precisely. Solely subway ridership knowledge have been used, as info on different private and non-private transport was unavailable.


The present research confirmed the effectiveness of strict lockdown measures in curbing the unfold of the extremely contagious SARS-CoV-2 Omicron variant. The success in Shanghai was largely as a result of discount of the asymptomatic unfold. Primarily based on the findings, the authors beneficial formulating differential lockdown methods depending on demographic composition and inhabitants density. This might additionally scale back the financial, social, and psychological prices of city-wide lockdowns.

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