What is the required quantity of COVID-19 vaccines for outbreak prevention? A global analysis based on growth curve modeling

Abstract Introduction The SARS-CoV-2 virus, which has the ability to rapidly spread, has caused multiple waves of deaths, resulting in nearly 7 million deaths in the past 3 years. During the early phase, most governments focused on implementing strict measures to cut off the transmission vector. However, the introduction of COVID-19 vaccines has changed the course of the fight against the COVID-19 pandemic. Methods A joinpoint regression analysis was used to identify mortality waves in 224 countries from February 22nd, 2020, to March 1st, 2023. Only countries with at least 2 waves were included in the analysis using Superimposition by Translation And Rotation (SITAR) to determine the growth curve of daily deaths and the impact of COVID-19 vaccine doses per population (CVDP), Cumulative incidence of COVID-19 (CIC), Rate of active cases per hospital bed (RAPHB), Active cases with diabetes (ACD), and Stringency index (SI). Results The analysis included over 3 million COVID-19 deaths from 82 countries to construct the growth curve. The increase in CVDP was associated with a decrease in wave size, intensity, and duration. However, an increase in CIC, ACD, RAHB, and SI was related to an increase in wave intensity and duration. The results suggest that maintaining CVDP at 120% (equivalent to 60% full doses) was associated with a decrease of 94.4% in COVID-19 deaths. Conclusion This research offers evidence for governments to enhance COVID-19 vaccination efforts in order to maintain herd immunity at 60% of the population and consider avoiding strict control measures.