Assessing Vaccination Prioritization Strategies for COVID-19 in South Africa Based on Age-Specific Compartment Model

Abstract

The vaccines are considered to be important for the prevention and control of coronavirus disease 2019 (COVID-19). However, considering the limited vaccine supply within an extended period of time in many countries where COVID-19 vaccine booster shot are taken and new vaccines are developed to suppress the mutation of virus, designing an effective vaccination strategy is extremely important to reduce the number of deaths and infections. Then, the simulations were implemented to study the relative reduction in morbidity and mortality of vaccine allocation strategies by using the proposed model and actual South Africa's epidemiological data. Our results indicated that in light of South Africa's demographics, vaccinating older age groups (>60 years) largely reduced the cumulative deaths and the “0–20 first” strategy was the most effective way to reduce confirmed cases. In addition, “21–30 first” and “31–40 first” strategies have also had a positive effect. Partial vaccination resulted in lower numbers of infections and deaths under different control measures compared with full vaccination in low-income countries. In addition, we analyzed the sensitivity of daily testing volume and infection rate, which are critical to optimize vaccine allocation. However, comprehensive reduction in infections was mainly affected by the vaccine proportion of the target age group. An increase in the proportion of vaccines given priority to “0–20” groups always had a favorable effect, and the prioritizing vaccine allocation among the “60+” age group with 60% of the total amount of vaccine consistently resulted in the greatest reduction in deaths. Meanwhile, we observed a significant distinction in the effect of COVID-19 vaccine allocation policies under varying priority strategies on relative reductions in the effective reproduction number. Our results could help evaluate to control measures performance and the improvement of vaccine allocation strategy for COVID-19 epidemic.

Usage of Compartmental Models in Predicting COVID-19 Outbreaks

“…In 2022, the Omicron variant, shown to be more transmissible and able to infect people with immunization, caused a new wave of infection in the USA ( 11 , 13 , 14 ). Considering the features of the Omicron variant, an adapted compartment model was developed and used to analyze the outbreak caused by such variant ( 56 ). As highlighted above, the compartmental model is extremely adaptive and can quickly be modified and implemented to address new data or issues.…”

Learning from the COVID-19 pandemic: a systematic review of mathematical vaccine prioritization models

“…In Zuo et al (2022), an ODE-based SEIQR model was fitted to South Africa and used to answer questions related to vaccine priortization and delay of the second dose. The authors found that, assuming limited vaccine availability, a delay of second doses leads to fewer severe COVID-19 cases.…”

Assessing the Impact of Vaccination on the Dynamics of COVID-19 in Africa: A Mathematical Modeling Study

“…Even though various research studies are being conducted in Africa, they largely focus on COVID-19 vaccination prioritization strategies [29][30][31] or vaccine acceptance [32][33][34].…”