Table 10 SEIR model parameters.

From: Exploring dependence of COVID-19 on environmental factors and spread prediction in India

Parameter

Brief data definition

Source/Reference

Suspected people (S[t])

The total number of suspected people in India are taken from WHO highlights showing a number of suspected samples for testing out of which some have positive results (SARS-CoV-2). A suspected individual contract the disease when interacts with the infected agents. Number of suspected people (S[t]) is equal to the total number of screened people

Ministry of Health and Family Welfare (MoHFW)62,63

Population (N)

Total population data is as per the census report. The population of India is about 133.92 crores

Census of India64

Probability of transmission (β)

Probability of transmission changes over time with number of infections and is used to derive β1 and β2

65

[S]→[I] (β1) susceptible to infected

[S]→[E] (β2) susceptible to exposed

Rate of transmission (β1 and β2)

The mortality rate of COVID-19 at about 3.434% in China and about 1.1% outside China. Rate of transmission is 1.5 - 4.5 for SARS-CoV-2, which is more than SARS rate of transmission.

46,66,67,68

β1 = k1 × β

β2 = k2 × β

Where, k1 = Probability of symptomatic infection (3 days) k2 = Probability of asymptomatic infection (15 days)

Incubation rate (σ)

2 to 14 days has been publicly reported for SARS- CoV-2.

Publicly available report of confirmed cases69,70,71

The period between the exhibition to an infection and the appearance of first symptom due to COVID-19.

Average rate of recovery or death (γ)

The average duration between the confirmation of detection to the time of removal i.e., death or recovered for India is taken as 14 days

70,72

γ = 1/Average recovery time

= 1/14

= 0.07

Number of contacts per person (r[t])

The number of contacts per person can be considered as the number of exposed people during inflow and outflow of the population it is estimated depending upon population, age group, household size, etc

The daily average number of contacts per person49,66,73

Exposed People (E[t])

The number of exposed people can be calculated by the inflow rate of people coming from other places and the outflow rate of people flowing out of the country

The latent population of country74,75

Infected People (I[t])

The total number of infected people in the country from January 2020 data is collected from online sources till June 9th 2020

WHO pandemic report

  1. Number of suspected people (S[t]) is equal to the total number of screened people. Total population (N) is as per the Celsius report. Probability of transmission (β) changes over time with number of infections and is used to derive β1 and β2, where β1 is suspected to infected and β2 is suspected to exposed. Rate of transmission is 1.5–4.5 for SARS-CoV-2, which is more than SARS rate of transmission. Incubation rate (σ2 to 14 days has been publicly reported for SARS- CoV-2. Average rate of recovery or death (γ), death or recovered for India is taken as 14 days. Number of contacts per person (r[t]) the number of contacts per person can be considered as the number of exposed people. Exposed People (E[t]), The number of exposed people can be calculated by the inflow rate of people coming from other places and the outflow rate of people flowing out of the country. Infected People (I[t]), the total number of infected people in the country from January 2020.
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