COVID-19 Projection for Tamil Nadu/தமிழ்நாடு

Data-driven modelling of pandemic, Nature Sci Rep 11, 6741 (2021)

May 10, 2021
Jul 21, 2021

Projections for confirmed, recovered, active, and deceased Covid-19 cases in Tamil Nadu are provided. The prevalence estimates from serosurveys have been included in the model. However, the scenario curves below show only the officially tested cases for Covid-19.
Model predictions updated/issued on May 24, 2021 .

Check the projections for India | Karnataka | Puducherry | Tamil Nadu

Assumptions of COVID-19 Wave II Model

  • 1.8L vaccinated every day, 50% as the second dose, and the vaccine is 70% effective. These numbers are very high compared to the actual number but expected that the vaccination drive would improve soon.
  • Two unreported cases for every reported case
  • Lockdown-like restrictions: local lockdown, city lockdown, strict curfew, etc. "Social distance" parameter in the model is fitted similar to the previous year (2020) lockdown
  • Due to an incubation period, it will take at least 7 to 10 days to see the effect of lockdown, and this is what implemented in our lockdown model.
  • Un-lock: Social distance parameter is restored to post-lockdown values of 2020
  • No inter-state transmission of COVID-19, including air travel

Scenario Analysis

  • S0: No Lockdown - worst-case
  • S1: Scenario I - 30-day lockdown (partial lockdown from 10th May and full lockdown from 24th May, 2021) with 50% effectiveness
  • S2: Scenario II - 30-day lockdown (partial lockdown from 10th May and full lockdown from 24th May, 2021)

Computational Model

  • Data from 23 March, 2021 is used partially to tune the parameters of the data-driven model. These results are current as of May 24, 2021.
  • The severity of the infection is taken into consideration while modeling the infectious death rate function (see the rate functions in the model).
  • What if the lockdown-like restrictions are not followed as in 2020?: All projections will follow the No-Lockdown scenario or even worsen.
  • What if the post-lockdown "social distance" parameter values follow the pre-lockdown values of 2021 instead of the post-lockdown values of 2020? The spread will be worse, and another scenario analysis needs to be performed.
  • What if the restrictions, inoculation, recovery, and herd immunity improve/worsen compare to the present situation? One can claim that the mathematical model has failed and proven wrong. In reality, we failed the mathematical model by feeding incorrect parameters.
  • District-wise numbers are computed with the Tamil Nadu parameters to compare the actual data of the respective district with the Tamil Nadu's trend. Hence, Districts' curves are not projections but indicate how the individual District got affected (better/worse) than the Tamil Nadu average.


  • COVID19-India API
  • Google Data Studio
  • Special thanks to all well wishers and colleagues for the discussion and feedback on our model.
  • Deepak wishes to acknowledge DST Inspire and Arcot Ramachandran Young Investigator Awards.
  • Sashi wishes to acknowledge SERB, DST, DRDO, DAAD and AvH for the grants that supported for the development of ParMooN.