Expert review of global real-world data on COVID-19 vaccine booster effectiveness and safety during the omicron-dominant phase of the pandemic. Expert Rev Vaccines.
Alvarez-Moreno C. 11/11/2022
Introduction
COVID-19 vaccines have been highly effective in reducing morbidity and mortality during the pandemic. However, the emergence of the Omicron variant and subvariants as the globally dominant strains have raised doubts about the effectiveness of currently available vaccines and prompted debate about potential future vaccination strategies.
Conclusion – future vaccine strategy
The results of our analysis suggest that the most effective way to achieve national vaccination coverage targets, particularly in resource-limited settings, would be to consider booster vaccines which have good safety and comparable effectiveness profiles against severe outcomes. The consistency of VE of current vaccines for severe disease against all variants, including Omicron, suggests a limited requirement for variant-specific vaccines at this time. Given the rate of mutation of the virus, pursuing variant or subvariant-specific vaccine development may distract from the immediate needs. Resources should instead be diverted toward improving coverage and access to currently available COVID-19 vaccines and challenging hesitancy and complacency.
This review reinforces the value of real-world evidence to support efforts advocating for the completion of primary series and booster vaccinations where appropriate, especially to restore waning VE against the more infectious Omicron variant and protect populations from severe outcomes, hospital admissions, and longer lasting post-COVID-19 complications, as well as mortality. Whilst acknowledging the limitations of our analysis, based on these findings and our own clinical experience, it is the opinion of this Expert Working Group that future vaccination strategies could incorporate annual booster shots for the general population alongside evaluation of the incremental benefits of the next generation of vaccines. Vaccination programs could include more regular, shorter interval, 4-6-monthly booster shots based on risk i.e. those who are elderly, and/or with comorbid conditions that increase the risk associated with a SARS-CoV-2 infection, as well as the use of a three-dose primary series to prolong the duration of protection, although data to support these recommendations is still lacking. The notion of more regular boosting than this would likely be neither beneficial nor sustainable for the general population. As we face up to an endemic COVID-19 future, important considerations must be given to optimizing protection in high-risk and immunocompromised populations that either respond poorly to vaccines or cannot be vaccinated.