Unless you are an infectious disease specialist or an epidemiologist, there’s a good chance that you had little to no interest in terms like R-naught, case fatality rate (CFR) and community transmission before January 2020.
R-naught is the rate of transmission of infection. So, an R-naught of three would mean that one sick person gives the infection to three healthy people on average. CFR is the percentage of patients who die from an infection. And community transmission is a stage when an infection has spread to such a degree that we can longer trace it back to source.
The advantages are that most of us are much more aware now of how pathogens spread and why we must each play our part in containing them. We are also much better primed now to follow difficult public health measures like physical distancing (previously called social distancing). Additionally the guidelines, infrastructure and knowledge we build now should give us greater confidence in our ability to handle any future outbreaks.
The big disadvantage, here, could be fixating on some public health tools at the expense of other information that could be crucial to manage this crisis precipitated by the SARS-CoV-2 coronavirus, which has made more than 21 lakh people sick and claimed nearly 1.5 lakh lives in the 16 weeks since it was first reported in Wuhan, China.
Nice-to-have figures versus useful data
CFR and R-naught, while extremely useful in general, are less so during an evolving health crisis.
Here’s why: Johns Hopkins University & Medicine data show that the CFR of COVID-19 varies from 0.2% in Singapore to 15.3% in Algeria – the same data set puts this rate at 3.3% for India. So while this data does tell us that different countries are faring differently with this virus, it does not tell us what to expect when the virus enters a new region of the world.
Similarly, the R-naught for the new coronavirus varies across the globe, depending on factors like population density and level of preparedness.
That said, any changes in R-naught at a district, state or country level could be significant – an upward trend would indicate a potential rise in infections, and necessitate more steps to build preparedness. On the other hand, a downward trend could be seen as reassuring: once the R-naught drops below 1, that’s when we can say that the outbreak is at an end.
Still more useful figures to collect and look at during this pandemic could be:
- The number and distribution of doctors and healthcare facilities in each community: We have mentioned in an earlier article that if we are able to map the healthcare personnel and infrastructure of this country accurately, then we can build better preparedness to deal with the COVID-19 infection in every community and every home of India.
- Size of elderly population in the country: India’s 104 million people over the age of 60 (according to Census 2011) should be another important figure for us during this outbreak. These are the people most likely to get severe symptoms of COVID-19 if they get the infection. Protecting them through strict home quarantine (with lots of social engagement and care from a safe distance) should be a top priority, to reduce the burden on critical care infrastructure as well as the COVID-19 death toll.
- Doubling rate: This is the number of days over which confirmed cases of coronavirus infection double. As of 17 April, this rate stood at 6.2 days in India compared with three days before the lockdown. It would be important to manage this rate once we come out of lockdown also.
- The number of people who need to become immune to the disease: Indian epidemiologist Dr Jayaprakash Muliyil has pointed out that once the lockdown is lifted, we should expect a rise in the number of COVID-19 cases. Now this number will naturally start to plateau at some point.
According to Dr Muliyil, when more than half the country’s population has contracted the infection and recovered from it, then the chances of transmission should go down automatically.
The key challenges, in the meantime, would be to protect the most vulnerable: older people and those with chronic illnesses like diabetes, heart disease and lung disease who could get very sick if they get COVID-19.
- Finally, the number and selection of people who should be tested for COVID-19: The RT-PCR test for COVID-19 can run samples from 64 people at once. Taking advantage of this, we could run pooled tests to identify clusters (rather than individuals) where infection exists. This, in turn, would help us quarantine the cluster as one unit where necessary. This would allow us to get the most out of the test kits we have available.
If we divvy-up our population into clusters of 50,000 to one lakh people each, and administer pooled tests till we are reasonably certain about whether infection exists or not in that cluster, it would also help us to quickly segregate zones with infection and safe zones before the lockdown ends.
Indeed the greatest test for India will come when the lockdown is lifted. Separating the important data from everything else may help us to take the necessary preventive actions going forward.
– This is the final article in a five-part series, supported by myUpchar. Nachiket Mor, PhD, is Visiting Scientist, The Banyan Academy of Leadership in Mental Health. Manuj Garg, PhD is Cofounder of myUpchar. Also in this series: Four things India can do to break the chain of COVID-19 transmission faster, For India to reduce COVID-19 toll, its senior citizens must be under strict quarantine, Unsung heroes who can strengthen India’s response to COVID-19 and Ingenuity and knowledge-sharing in the time of Covid-19.
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