The Infection Fatality Ratio (IFR) estimates the percentage deaths in all those with an infection: the detected (cases) and those with undetected disease (asymptomatic and the not-tested group).

The IFR is used to model the estimated number of deaths in the population at large. If it’s a large number approaching one percent, then the modelled outputs can report an alarming number of fatalities – providing the impetus for lockdowns.

Early in the pandemic, Imperial College London’s Report 9 modelled the impact of covid based on a publication by Verity et al. on 13 March 2020, which estimated the IFR as 0.9 percent.

This IFR gave rise to the modelled estimates ‘in an unmitigated epidemic, we would predict approximately 510,000 deaths in GB and 2.2 million in the US.’