# Mathematical modelling analysis of Covid lockdowns

A study suggests that repeated and multiple lockdowns are beneficial and far from being unnecessary

Now that we have witnessed multiple lockdowns that have been imposed with the understanding that the imposition is going to contain the spread of the virus, let us take a glance at the recent mathematical analysis of the effect of these lockdowns.
In an article published in the prestigious journal Scientific Reports, Nature, on April 13, 2021, Antonio Scala, a research scientist at the CNR-ISC institute for Complex Systems, came up with a detailed analysis of whether multiple lockdowns served any purpose. In the words of Scala, “[w]hile vaccination is the optimal response to an epidemic, recent events have obliged us to explore new strategies for containing worldwide epidemics, like lockdown strategies, where the contacts among the population are strongly reduced to slow down the propagation of the infection.”
Mathematical modelling is a very useful branch of study wherein one can get a good understanding of how complex situations are modelled for a deeper and better understanding and for taking the right or the most appropriate decisions. Taking the right decisions at the right time and the right place may not be easy, but that is precisely the situation in which modelling comes in handy. Regarding epidemics or the general spread of any contagious disease, the fact remains that mathematical modelling is not just an option but is currently the only way forward. These models help us understand how infectious diseases behave in terms of their spread, outcomes, effect on public health, and hopefully on the economy and stability of a country or a nation. One can take the example of how much mankind has progressed in the domain of weather forecasting. Though one cannot claim that predictions and deductions are interchangeable, one cannot give a wide berth to the fact that being good at predictions is a blessing and a scientific study in its own right.
The mathematical model of an epidemic helps us estimate several crucial parameters that, in turn, help us get wind of the facts that are otherwise hard to know. In the words of the author, “[s]uch models help us to estimate important epidemiological parameters like the potential growth rate of an epidemic, the total fraction of people that will get infected, or the fraction of people to vaccinate to stop the epidemic.”
Among the most common models that help better mitigate the effects of infection are the SIR and the SIER models. The SIR model takes into consideration the number of Susceptible individuals, the number of Infected individuals, and the number of Recovered individuals, thereby explaining why it is called so. The SIER model, on the other hand, takes into consideration a fourth number, the number of Exposed individuals, that is, the individuals that have been exposed to the virus but have not yet been infected by it. In what has been found, vaccination is a very good option for curtailing the spread of the virus.
The author explains the situation in which vaccination is either not available or is insufficient to combat the pathogen. This is the situation wherein the concepts like social distancing and lockdown come into the picture. These non-pharmaceutical measures could be understood as the last resort to fighting the invisible enemy. Just understand what happens when a lockdown is lifted. Usually, lockdowns are lifted when the number of present infections reaches its final stage. However, this is the situation that poses a diabolical threat. Once a lockdown is lifted, complacency and a sense of urgency result in another need for a lockdown. And the so-called vicious circle starts taking a toll on the population.
As per the findings, the author goes on to claim that repeated and multiple lockdowns are beneficial and far from being unnecessary. In the words of Scala, “[r]epeated lockdowns have a beneficial effect, reducing the final size of the infection, and that they represent a possible support strategy to vaccination policies.”

—The writer is Assistant Professor at Govt Degree College Sopore. fi[email protected]