The Population-Wide Risk-Benefit Profile of Extending the Primary COVID-19 Vaccine Course Compared with an mRNA Booster Dose Program

• Published in: Vaccines (Basel) 2022-01, Vol.10 (2), p.140
• Main Authors: Shiri, Tinevimbo, Evans, Marc, Talarico, Carla A, Morgan, Angharad R, Mussad, Maaz, Buck, Philip O, McEwan, Phil, Strain, William David
• Format: Article
• Language: English
• Subjects: Age groups; boosters; Coronaviruses; COVID-19; COVID-19 vaccines; Disease transmission; Guillain-Barre syndrome; Heart diseases; Hospitalization; Infections; modelling; mRNA; Myocarditis; Pandemics; Pericarditis; Population; population risk; Primary care; Risk; Severe acute respiratory syndrome coronavirus 2; Strategy; Vaccination; Vaccine efficacy; Vaccines; Viral diseases
• ISSN: 2076-393X; 2076-393X
• DOI: 10.3390/vaccines10020140

The vaccination program is reducing the burden of COVID-19. However, recently, COVID-19 infections have been increasing across Europe, providing evidence that vaccine efficacy is waning. Consequently, booster doses are required to restore immunity levels. However, the relative risk-benefit ratio of boosters, compared to pursuing a primary course in the unvaccinated population, remains uncertain. In this study, a susceptible-exposed-infectious-recovered (SEIR) transmission model of SARS-CoV-2 was used to investigate the impact of COVID-19 vaccine waning on disease burden, the benefit of a booster vaccine program compared to targeting the unvaccinated population, and the population-wide risk-benefit profile of vaccination. Our data demonstrates that the rate of vaccine efficacy waning has a significant impact on COVID-19 hospitalisations with the greatest effect in populations with lower vaccination coverage. There was greater benefit associated with a booster vaccination strategy compared to targeting the unvaccinated population, once >50% of the population had received their primary vaccination course. The population benefits of vaccination (reduced hospitalisations, long-COVID and deaths) outweighed the risks of myocarditis/pericarditis by an order of magnitude. Vaccination is important in ending the COVID-19 pandemic sooner, and the reduction in hospitalisations, death and long-COVID associated with vaccination significantly outweigh any risks. Despite these obvious benefits some people are vaccine reluctant, and as such remain unvaccinated. However, when most of a population have been vaccinated, a focus on a booster vaccine strategy for this group is likely to offer greater value, than targeting the proportion of the population who choose to remain unvaccinated.