What is R-number, why you should know about it, and what it says about COVID-19 situation in India Firstpost 16 hours ago FP Staff New Delhi: From CFR (case fatality ratio) to subunit and mRNA vaccines to spike protein, words previously restricted to academic journals and research papers have appeared at the forefront of public discussion during the COVID-19 outbreak. One such term is the R-number, which several policymakers across the globe have kept at the core of their strategies against the pandemic. At the same time, some infectious disease experts say the ominous-sounding R could be getting too much importance.