Regional Contact Networks and the Pandemic Spread of COVID-19 in India

Chapter 0: Epidemics and Networks- Why Networks Matter

At a fundamental level, epidemics spread over a human to human network — where carriers spread the contagion by coming in contact with other people (see a simple illustration in Figure 1). These networks are established through work & social interactions, transport/ travel or simply shared physical proximity. Established models for epidemic spread assume random and homogeneous mixing between individuals, which might not be realistic since the general population has defined organizational units (geographical, social etc.) and individuals tend to interact within their sphere of influence. These “links” between individuals form a network and contagions spread along the infection paths of these networks.

Figure 1: A simple illustration of an epidemic network across time. Simulated from a network Susceptible-Infected-Recovered (SIR) model, where the nodes are individual patients: blue are susceptible, red are infected, and green are recovered individuals. One time-step in the figure represents 10 units of time in the original scale of transmissions.
Figure 2: Network of patients infected with COVID-19 across Indian states and union territories, with each dot representing one patient and the color of the dot representing the state in which the patient was first detected and confirmed as a case. Edges are defined by whether two patients are located within a band of two degrees of latitude and longitude of one another. Note: This map is used for illustrative purpose only. Actual territorial boundaries might differ. We have removed the edges between nodes that are too close for visual clarity

Chapter 1: What is next and how state-level responses can change the future

We have built a network-based forecaster for predicting the number of infected cases over short-term future (next three months) and the spread over specific geographical regions over potential contact networks for every state in India. We focus on three potential scenarios (more scenarios can be accessed using our online web-application):

  1. Forecast the number of affected individuals for each state in India for the next three months and which states emerge as hotspots based on emerging geo-coded data.
  2. What is the potential impact on health care systems and facilities?
  3. What measures can be taken to mitigate and contain the contact networks.
(a) Low intensity spread (R0=1.5)
(b) Medium intensity spread (R0=2)
(c) High intensity spread (R0=2.5)

Chapter 2: How can India build healthcare capacity?

Healthcare forecasting in India during COVID-19 Pandemic

Figure 4: Waterfall plots showing the shortfall of hospital beds and ventilators across Indian states and union territories on the peak day of incidence of new cases. These estimates are based on a SEIR model with the reproduction number R0=2 under sporadic adherence to containment and mitigation protocols. The normal occupancy rate of the hospital beds is varied as 25% (Panel a), 50% (Panel b), and 75% (Panel c).
Figure 5: Map of India showing the shortfall of hospital beds across Indian states and union territories on the peak day of incidence of new cases. These estimates are based on a SEIR model with the reproduction number R0=2 sporadic adherence to containment and mitigation protocols. The normal occupancy rate of the hospital beds is varied as 25% (Panel a), 50% (Panel b), and 75% (Panel c). Note: These maps are used for illustrative purpose only. Actual territorial boundaries might differ.
Figure 6: Word cloud representing the global prevalence of co-morbidities in the COVID-19 infected patients. The font size of the word is proportional to the square-root of the number of times a given comorbidity is observed.

Chapter 3: What lies ahead…

Pro-active measures taken by India The sheer size of the population of India is both a bane and a boon. While the large population density has its disadvantage of making contact tracing and isolation a difficult task, India leverages on its young population and strong information network to fight the disease with grit. Even before the first reported case had been registered in the last week of January, India started screening international travelers at select airports, and extended the same to other major airports, train stations and other ports of entry. There are arguments criticizing the delay in complete halt of domestic and international travel, but the decision of imposing a country-wide lockdown, though seen as a harsh measure given the state of the economy of the country and the ordeal of India’s migrant workforce and the poor, may have come in good time based on our projections.

  1. Increasing levels of testing across states, especially in hotspots
  2. Increasing the number of quarantine facilities, hospital beds and isolation units
  3. Extending financial help towards daily wage workers
  4. Ensuring the supply of PPEs and adequate medicines across the country
  5. Exporting potential drug Hydroxychloroquine to affected countries in need
  6. Creating SAARC COVID-19 Emergency Fund to tackle and fight the pandemic in South Asia
  7. Implementing drone surveillance systems to ensure social distancing, and improving sanitization processes
  8. Strictly monitoring zonal-level implementation of lockdown measures
  9. Launching the mobile app, Aarogya Setu, in a bid to keep the citizens informed about the COVID-19. Through a location-based social network construction, it provides information on whether the user has interacted with anyone who has tested positive for the disease.

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