Pre vaccine fatality rates

Lower than previously thought Impact of non-pharmaceutical interventions (NPIs) to reduce COVID-19 mortality and healthcare demand (16th March 2020) Imperial College COVID-19 Response Team https://www.imperial.ac.uk/media/imperial-college/medicine/sph/ide/gida-fellowships/Imperial-College-COVID19-NPI-modelling-16-03-2020.pdf We assumed Incubation period of 5.1 days Infectious 12 hours before to 4.6 days after R0=2.4 Non-uniform attack, applied to the GB population Result in an IFR of 0.9% with 4.4% of infections hospitalised 10.4 day stay 30% of hospitalised, ICU (50% death rate) (not accounting for the potential negative effects of health systems being overwhelmed on mortality) Age-stratified infection fatality rate of COVID-19 in the non-elderly informed from pre-vaccination national seroprevalence studies Stanford California, Rome, Montreal https://www.medrxiv.org/content/10.1101/2022.10.11.22280963v1 40 eligible national seroprevalence studies, covering 38 countries with pre-vaccination seroprevalence data. For 29 countries publicly available age-stratified COVID-19 death data, and age-stratified seroprevalence information were available, and were included in the primary analysis. IFRs for 0 to 59 years median IFR = 0.035% (IQR, 0.013 - 0.056%) Without accounting for seroreversion (average time from seroconversion to seroreversion at 3-4 months) IFRs for 0 to 69 years IFR = 0.095% 0 to 19 years IFR = 0.0003% 20 to 29 years IFR = 0.003% 30 to 39 years IFR = 0.011% 40-49 years IFR = 0.035% 50-59 years IFR = 0.129% 60-69 years IFR = 0.501% At a global level Pre-vaccination IFR, may have been as low as, 0 to 59 years = 0.03% 0 to 69 years = 0.07% Global population 94% younger than 70 years 91% younger than 65 years 86% younger than 60 years The current analysis suggests a much lower pre-vaccination IFR in non-elderly populations than previously suggested. Large differences did exist between countries and may reflect differences in comorbidities and other factors. These estimates provide a baseline from which to fathom further IFR declines with the widespread use of, Vaccination Prior infections Evolution of new variants. Unmitigated epidemic (March 2020) UK deaths = 510,000 (168,913) US deaths = 2.2 million (1,065,152) During 2021 and 2022 Vaccination, new variants, prior infections, resulted in a marked decline in the IFR