A mathematical model developedby four senior researchers, two of them from the Indian Statistical Institute, has predicted that a localised lockdown of around 29 days in a community of 43-68 people can temporarily halt the spread of coronavirus, and help eradicate the contagion in 2-3 years in the country.Indranil Mukhopadhay, senior ISI professor and head of the Human Genetics Unit, told PTI on Monday while the temporary eradication of the "spread time" of the virus could be around 29 days, the time taken for total extinction can be around 2-3 years with the virus expected to make a comeback later but losing its sting to be a pandemic any more."COVID-19 being an entirely new disease, complete data for any definitive prediction is not there and hence the figures in our model can vary - say the 29 days limit for temporary eradication can be 39 days but probably won't be 200 days," Mukhopadhay said, pointing out that it was a mathmetical model made with the available data.The model was based on data collected from the month of March to April 1, he said in reply to a question.Underscoring the need for total localised lockdown, the researcher said that lockdown, in its true sense, may not be totally enforceable in a vast and diverse country like India with such a high density of population.A focused approach where a high-risk population in a certain locality is put under intensive screening for over four weeks is more advisable to prevent group transmission, that will result in zero infection at one point, he said.If the number of high risk population in a locality is a bit high, there can be clusters possibly having around 50 people in each group, which is called "critical community size(CCS)".There can be more than one such cluster in the pocket depending on the high risk population number in that area, Mukhopadhyay said.The model was based on four parameters - 'susceptible', 'infected', 'exposed' and 'recovery', he said."In our future study we have to keep in mind the susceptibility of vegetable vendors and fish sellers in markets who are present every day instead of buyers who can come once in a week or fortnight, and find out whether curtailing regular market hours will be better for them," he said.Asked about the possibility of the virus making a comeback after 2-3 years losing its lethal nature, Mukhopadhyay said, even if one infected person is identified, the local quarantine policy will be in force, where a group of people, the maximum being CCS, may stay together in clusters.The other researchers include Bandana Sen, a senior researcher with the All India Institute of Hygiene and Public Health and Sarmistha Das, a senior researcher at ISI."Following lockdown rules strictly is the only way to fight out COVID-19 in absence of specific treatment or vaccine," Mukhopadhay said.ISI Director Sanghamitra Bandyopadhyay said, "Our researchers are doing many important projects related to COVID-19 and we are working with various government agencies to help them fight the pandemic.
