The total number of active COVID-19 cases has surged up to 12,578 across India and the virus has claimed 426 lives, according to the latest data released by the Government of India. While the figures are already alarming, there is a possibility that the number of cases reported is far less than the actual number of people infected with coronavirus.
According to a projection made by researchers from Imperial College London, the disease multiplies silently among populations, which is why curbing its spread is so complicated. Between March 22 to March 29, the number of cases reported in India was 2,395 while the short-term forecast done according to the research indicates that the actual figure was somewhere between 16,800-23,600. Similarly, the number of deaths by April 11 would likely be somewhere between 119 and 567. The figure reported on April 10 was 288.
One of the authors of the research has suggested how short-term forecasts are more reliable and stable as compared to the reported cases over time.
Two factors have been kept in mind while conducting this research. One, the true number of cases ascertained by first looking at the number of deaths in the previous two weeks. Two, according to Sangeeta Bhatia, the lead researcher on the project, "If we assume that all deaths due to COVID-19 are reported, then very roughly we can look at the expected number of fatalities based on the case fatality ratio, to estimate the number of underlying cases that would result in the observed number of deaths."
How does this help? Well, the ratio between reported and underlying cases can then be used to predict the number of deaths in the following week. According to this particular analysis, India’s disease transmission rate stands at 3.11, which means that the average number of people infected further by one patient is over 3 persons.
Reasons Behind Variability In Reporting
There are possibly two main reasons why not all cases or people infected are being identified.
The main reason could be the existence of asymptomatic carriers. According to Bhatia, "One of the issues is that cases with Covid-19 can present with a range of symptoms--some of them, for example, are too mild to be reported, and hence cannot be tested."
Limited testing capacity: this is another major reason why India is not reporting a higher number of cases. "Another factor that contributes to the variability in reporting is the limited testing capacity in each country. Related to this limitation is the decision about whom to test. In the early stages of the outbreak, India, like many other countries, was testing only travellers from affected regions or contacts of travellers," Bhatia added.
The Scare Of Silent Spreading
While it is extremely important to detect the coronavirus infected/carriers, it is also becoming increasingly difficult due to the silent spread. Silent spreaders can be divided into three categories: asymptomatic, presymptomatic and very mildly symptomatic.
Asymptomatic carriers are the people who carry the active virus in their body but never develop any symptoms. Therefore, it's hard to figure out if that particular someone has the disease if they are showing no signs of it.
Presymptomatic carriers are the ones who have been infected and are incubating the virus but don't show symptoms for a long period of time.
Very mildly symptomatic carriers are those who feel slightly unwell from a COVID-19 infection but still continue to maintain contact with others. This is why social distancing is so important.
What we don't know yet is how many people are mingling within the population without even having the slightest of an idea if they've contracted coronavirus. The study conducted clearly states that a COVID-19 patient on average has been infecting three more people (before the nationwide lockdown came into effect) than what India's transmission rate implies. The number is closer to the worst-case scenario transmission rate of 4 identified by the Indian Council of Medical Research.
If India wants to stop coronavirus from spreading, the transmission rate needs to be <1. Hopefully, the lockdown extension to May 3 will play a vital part in doing so. Till then, let's follow govt's new guidelines, stay home and practise social distancing to save ourselves and others.
Featured Image: The Ernakulam district administration