NEW DELHI/UNITED NATIONS: The COVID-19 pandemic may be over in India around mid-September, claim two public health experts from the Health Ministry who used a Mathematical model-based analysis to draw this projection while a top WHO expert warned that the risk of the disease exploding in the country remains as it moves towards unlocking the over two-month-long lockdown.
The analysis shows that when the number of infected becomes equal to those removed from circulation by recovery and death, the coefficient will reach the 100 per cent threshold and the epidemic will be “extinguished”.
The analysis, published in the online journal Epidemiology International, has been done by Dr Anil Kumar, Deputy Director General (Public Health) in the DGHS, and Rupali Roy, Deputy Assistant Director (Leprosy) DGHS in the Health Ministry.
They used the Bailey’s mathematical model to draw the projection. This stochastic Mathematical mode takes into consideration the distribution of the total size of an epidemic, involving both infection and removal. The model employed was of the ‘continuous infection’ type, according to which infected individuals continue as sources of infection until removed from circulation by recovery or death. In this, the removal rate is worked out after calculating the percentage of removed persons in the infected population. Further, regression analysis has been done, to get the results regarding relationship between the total infection rate and the total recovery rate.
According to the document, the actual epidemic in India started on March 2 and since then the number of confirmed cases has been rising. For doing the analysis experts used the secondary data for COVID in India from worldometers.info on the number of cases reported in the country since March 1 to May 19 along with total of cumulative recovered cases and cumulative deaths.
Regression Analysis (Linear) of Bailey’s Relative Removal Rate (BMRRR), COVID 19, in India shows that the linear line is reaching to 100 in the middle of September, the research paper said. “So it may be interpreted that at that point of time the number of infected will be equal to the number of removed patients, and that’s why the coefficient will reach 100 per cent threshold,” it said while cautioning that this is a stochastic model and outcome will depend on variance structure around it.
There are two main stochasticities, demographic and environmental, it said. “So the decision-makers must try to control and modify variables related to these two factors so that Bailey’s Relative Removal Rate (BMRRR) continues to go up,” the research paper stated. This can be an important tool in the hand of Central, state and district authorities in decision-making and taking appropriate action at this time in the virus containment, epidemic situation management and control the pandemic spreading in the country, it said.
Pointing out the limitations of the analysis, the paper stated that it is based on collected secondary data for a specific period of time to fit and estimate the basic case number, infection rate, and recovery rate of COVID-19. “When we apply any mathematical model, we make some assumptions for a certain period of time, impact of a few factors are being ignored such as population birth rate and natural mortality. Natural calamity, unpredictable population movement and important national or international events may have significant influence on this model,” it said. “With the continuous release of epidemic data these important indicators may undergo significant changes in the spread of COVID-19 among the population,” it said.
Unexploded may explode
The coronavirus disease has not “exploded” in India, but the risk of that happening remains as the country moves towards unlocking its nationwide lockdown that was imposed in March to contain the COVID-19, according to a top WHO expert.WHO Health Emergencies Programme Executive Director Michael Ryan on Friday said the doubling time of the coronavirus cases in India is about three weeks at this stage. “So the direction of travel of the epidemic is not exponential but it is still growing,” he said, adding that the impact of the pandemic is different in different parts of India and varies between urban and rural settings.
“In South Asia, not just in India but in Bangladesh and…in Pakistan, other countries in South Asia, with large dense populations, the disease has not exploded. But there is always the risk of that happening,” Ryan said in Geneva. He stressed that as the disease generates and creates a foothold in communities, it can accelerate at any time as has been seen in a number of settings.
Ryan noted that measures taken in India such as the nationwide lockdown have had an impact in slowing transmission but the risk of an increase in cases looms as the country opens up.
“The measures taken in India certainly had an impact in dampening transmission and as India, as in other large countries, open up and as people begin to move again, there’s always a risk of the disease bouncing back up,” he said. He added that there are specific issues in India regarding the large amount of migration, the dense populations in the urban environment and the fact that many workers have no choice but to go to work every day. (PTI)
