A team of researchers from the Centre of Excellence for Computational Mathematics and Data Science at the Indian Institute of Technology Madras (IIT-M) has calculated that as on January 13, an infected person spreads the virus on an average to two others (2.2). As on January 10 it was three others (3.5) and on January 6, it was four persons.
The team includes S. Sundar, professor and co-principal investigator; Neelesh S. Upadhye, associate professor and principal investigator; and Jayant Jha, assistant professor at the Department of Mathematics. “The R nought (R0) value reveals that one infected person can infect three persons on an average. We assume that the neighbours are not infected,” explained Professor Sundar.
The model helps to understand the stringency with which safety protocols are observed. “The message is that R0 is an indicator of the rate of spread of the disease. We can also tell, with given data, how the stringency measures have affected the spread of the disease,” he said.
The R0 fell below 1 between the first and second waves of the pandemic, but between the second and third wave the value was close to one and then it rose suddenly. “Between the second and third wave, the gap was much smaller,” said Mr. Jha.
The researchers observe that there has been a waning of immunity, especially among health workers. The government should take a policy decision on providing the booster dose to those who show a waning immunity a year after the second dose as these persons may again become susceptible to the disease.
“What is clear is that depending on the restrictions imposed by the government, the number of people taking the vaccine, the region where the government protocol for restrictions are imposed, definitely our model will give a clear picture of R0. Based on vaccination data, the way the disease is getting spread will vary. Vaccinated people are less likely to have severe disease. The virus will be there but its severity will wane in the course of time,” Mr. Upadhye added.
The team has calculated the R0 value and is validating its model. The researchers say they have calculated the value based on actual COVID-19 data. The calculation does not take into consideration the variants of the virus, however. “We are considering all variants together. We pick up the data from across the world and are specializing in the Indian context,” said Mr. Upadhye.
The team has calculated the R0 value for every State and developed separate models to understand how and which State is responding to the infection. “Even vaccination impact needs to be brought in before we predict how the third wave will progress,” Prof. Sundar said.
