Mathematical model by IISER predicts dip in nationwide Covid cases by mid-May

A new mathematical model by Kolkata-based Indian Institute of Science Education and Research (IISER) has predicted that if the current nationwide lockdown continues,

A new mathematical model by Kolkata-based Indian Institute of Science Education and Research (IISER) has predicted that if the current nationwide lockdown continues, active Covid-19 infections in India are likely to start decreasing by the second week of May and the cycle of the disease in the first phase is likely to end between early to mid-July.

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This means the number of those infected - denoted by the reproduction number R0 - will drop to 0.5 under the scenario of stringent lockdown or quarantining all infected individuals. R0 (R nought) is a measure of the number of individuals who may contract the infection from one Covid-positive patient. IISER’s model has calculated Covid-19’s reproduction number at R5 at the start of the lockdown.

Active infections simulated by the model comprises individuals tested positive for the novel coronavirus as well as those who are asymptomatic - the latter are not considered in official infection numbers.

“Assuming the strength of the lockdown is not relaxed and continues till early July, our prediction is that active infections will keep rising and reach a peak before beginning to fall around May 17. The first wave will end by mid-July when patient recovery rates reach saturation point,” said Dibyendu Nandi, professor and lead researcher, IISER. “If the numbers don’t start falling in the next seven days, it will imply that the lockdown saw relaxations this week. However, if the lockdown is relaxed, active infections will peak early August and the numbers will be catastrophic.”

The model’s algorithm has calculated 60,000 active infections (best case scenario) as the peak, and the upper range at 1.35 lakh as the worst case scenario, assuming transmission rates will be higher.

Had the lockdown started end of February, the model estimated that the total number of active infections would not exceed 20,000; the peak would be less than 10,000; and India would be nearing the end of the first wave.

With vulnerable groups such as daily wage labourers and migrants impacted the most, IISER researchers said the best strategy to bring the pandemic’s first wave under control is to undertake active testing, contact tracing quarantine and containment of serious hotspots and slowly relax lockdown.

“Since India has not reached peak infections, the situation is more dangerous now than the beginning of the lockdown because of the higher number of infected individuals in the system. Completely lifting the lockdown therefore will remove any advantages that the country has so far achieved,” said Nandi.