The Global case-fatality rate of COVID-19 has been declining disproportionately between top vaccinated countries and the rest of the world
Authors: Haider Najmul , Hasan Mohammad Nayeem , Khan Rumi A , McCoy David , Ntoumi Francine , Dar Osman , Ansumana Rashid , Uddin Md. Jamal , Zumla Alimuddin , Kock Richard A 
Published: January 2022

AbstractGlobally 58.83% human population received at least one dose of the COVID-19 vaccines as of 5 January 2021. COVID-19 vaccination rollout is progressing at varied rates globally and data on the impact of mass vaccination on infection and case-fatality rates require definition. We compared the global reported cumulative case-fatality rate (rCFR) between top-20 countries with COVID-19 vaccination rates (>125 doses/100 people) and the rest of the world, before and after commencement of vaccination programmes.We considered the 28th day of receiving the first vaccine in the world as a cut-off to compare the pre-vaccine period (Jan 1, 2020 – Jan 5, 2021) and the post-vaccine period (Jan 6, 2021-Jan 5, 2022). We used a Generalized linear mixed model (GLMM) with a beta distribution to investigate the association between the CFR and potential predictors of each country and reported the relative risk (RR) of each variable.The mean rCFR of COVID-19 in the top-20 countries with vaccination rates was 1.83 (95% CI: 1.24-2.43) on 5 Jan 2021 and 1.18 (95% CI: 0.73-1.62) on 5 Jan 2022. The CFR for the rest of the world on 5 Jan 2021 was 2.32 (95% CI: 1.86-2.79) and 2.20 (95% CI: 1.86-2.55) on 5 January 2022. In Sub-Saharan Africa, the CFR remained roughly unchanged at 1.97 (95% CI: 1.59-2.35) on 5 Jan 2021 and 1.98 (95% CI:1.58-2.37) on 5 Jan 2022. The GLMM showed vaccination (/100 population) (RR:0.37) and Stringency Index (RR:0.88) were strong protective factors for the country’s COVID-19 CFR indicating that both vaccination and lockdown measures help in the reduction of COVID-19 CFR.The rCFR of COVID-19 continues to decline, although at a disproportionate rate between top vaccinated countries and the rest of the world. Vaccine equity and faster roll-out across the world is critically important in reducing COVID-19 transmission and CFR.Key QuestionsWhat is already knownVaccination can reduce the case-fatality rate of COVID-19. Globally, the COVID-19 vaccination rollout is progressing at varied rates.What are the new findingsIn the top-20 countries with vaccination, >200 doses of vaccines are given per 100 people on 5th Jan 2022, In the rest of the word, the figure is 105, and in Sub-Saharan Africa (SSA) only 15.72After the introduction of COVID-19 vaccination the reported case-fatality rate (rCFR) of COVID-19 has reduced by 35% in the top-20 countries with vaccination, 8% in the rest of the world roughly unchanged in SSA.The doses of COVID-19 vaccines (/100 people) and rCFR has a negative correlation on 5 Jan 2022 (r=-0.296, p<0.001).The COVID-19 vaccination and Stringency Index are strong protective factors for the country’s COVID-19 rCFR indicating that both vaccination and lockdown measures help in reduction of COVID-19 rCFR.What do the new findings implyThe disproportionate case-fatality rate of COVID-19 between top vaccinated countries and the rest of the world demand fast and equitable vaccine rollout globally to reduce COVID-19 transmission and CFR