Wednesday, April 1, 2020

COVID-19: Lessons from coronavirus outbreak in China and formulating a strategy

Hello awesomites!

The following information is regarding the situation of COVID19 in China and how did China manage to reduce the incidence of new cases.

Image by  Nakeya. Medicowesome 2020

COVID-19 rapidly spread from a single city to the entire country in just 30 days. Initially - mixed outbreak pattern with early cases suggestive of a continuous common source potentially zoonotic spillover, and later cases suggestive of a propagated source as the virus began to be transmitted from person to person.

Source of the image: Journal of the American Medical Association

The difference between the cases by date of symptom onset curve (blue) and the cases by date of diagnosis curve (orange) illustrates lag time between the start of illness and diagnosis of COVID-19 by viral nucleic acid testing. 

CONFIRMED CASESDiagnosis based on positive viral nucleic acid test result on throat swab samples

SUSPECTED CASES: Diagnosis based on symptoms and exposures only, no test was performed because testing capacity is insufficient to meet current needs.

DIAGNOSED CASES: In these cases, no test was performed but the diagnosis was made based on symptoms, exposures, and presence of lung imaging features consistent with coronavirus pneumonia.

ASYMPTOMATIC CASES: Diagnosis by positive viral nucleic acid test result but lacking typical symptoms including fever, dry cough, and fatigue

                     Source of the image: Journal of the American Medical Association

1. The total number of COVID-19 cases is likely higher due to inherent difficulties in identifying and counting mild and asymptomatic cases. (81% were mild cases)

2. Insufficient testing capacity for COVID-19 in China means that many suspected and clinically diagnosed cases are not yet counted in the denominator. (To calculate actual case fatality rate)

3. Cluster identification: It appears that considerable transmission is occurring among close contacts.

4. The timing of the COVID-19 outbreak, prior to China’s annual Lunar New Year holiday. People return to their family homes. Knowing this meant each infected person could have numerous close contacts over a protracted time and across long distances.

OPTIONS LEFT: Isolation, quarantine, social distancing, and community containment.

China adopted a containment strategy to manage the outbreak in areas with no cases vs. sporadic cases vs. clusters of cases vs. community-level transmission.

Image by Upasana Yadav

                                                 Source: Tomas Pueyo article on medium 


Specimens from both the upper respiratory tract (URT; nasopharyngeal and oropharyngeal) and lower respiratory tract (LRT; expectorated sputum, endotracheal aspirate, or bronchoalveolar lavage) are collected for COVID-19 testing by PCR. 

According to preliminary data from Guangzhou CDC as of 20 February, the virus can initially be detected in upper respiratory samples 1-2 days prior to symptom onset and persist for 7-12days in moderate cases and up to 2 weeks in severe cases. 

Kits were made available in all provinces:-
RT-PCR kits
Isothermal amplification kit
Virus sequencing product
Colloidal gold antibody detection kits





Health QR codes were established for everyone in the city and everyone who entered the city. 
Green code - allows you to move freely 
Yellow code - requires a seven-day self-quarantine
Red code - requires a 14-day self-quarantine

The yellow and red codes can be turned green after the quarantine time. Green color codes are allowed in public spheres after using the designated QR code at metro stations, offices, station

Big Data and Facial recognition

App using pay wallet services like Alibaba’s Alipay, Ant’s wallet
CCTV cameras - to ensure that those who are quarantined don’t step out.

Baidu has also made tools to build effectively screen large populations. It has also built an AI-powered infrared system that can detect a change in a person’s body temperature. It is currently being used to identify passengers who are potentially infected where it can examine up to 200 people in one minute without disrupting passenger flow, says the MIT Review.


Image source: Report of the WHO-China Joint Mission on Coronavirus Disease 2019 (COVID-19) 
Written by  Upasana Yadav


1. Wu Z, McGoogan JM. Characteristics of and Important Lessons From the Coronavirus Disease 2019 (COVID-19) Outbreak in China: Summary of a Report of 72 314 Cases From the Chinese Center for Disease Control and Prevention. JAMA. Published online February 24, 2020. doi:10.1001/jama.2020.2648 Retrieved 1 April 2020, from
2. Pueyo, T. (2020). Coronavirus: Why You Must Act Now. Retrieved 1 April 2020, from
3. Ferguson, N, et al. (2020). Impact of non-pharmaceutical interventions (NPIs) to reduce COVID19 mortality and healthcare demand [PDF]. WHO Collaborating Centre for Infectious Disease Modelling. Retrieved from 
4. Pueyo, T. (2020).  Coronavirus: The Hammer and the Dance. Retrieved 1 April 2020, from
5. Chaturvedi A. (2020) Technology used in China to combat Covid 19 Retrieved 1 April 2020, from
6. Report of the WHO-China Joint Mission on Coronavirus Disease 2019 (COVID-19) [PDF]  Retrieved 1 April 2020, from

1 comment:

  1. Simply loved it!
    Its knowledgeable , Crisp and Concise!
    The author must have worked real hard for compiling it.
    Thanks a lot to you Upasana and your team:)


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