Much of the world’s population had already been infected with COVID-19 by the time that the Omicron variant emerged at the end of 2021, but the scale of the Omicron wave was larger than any that had come before or since, and it left a global imprinting of immunity which changed the COVID-19 landscape. In this study, we simulate a South African population, and demonstrate how population-level vaccine effectiveness and efficiency changed over the course of the first two years of the pandemic. We then introduce three hypothetical variants and evaluate the impact of vaccines with different properties. We find that variant-chasing vaccines have a narrow window of dominating pre-existing vaccines, but that a variant-chasing vaccine strategy may have global utility, depending on the rate of spread from setting to setting. Next-generation vaccines might be able to overcome uncertainty in pace and degree of viral evolution.

Fuente: Cell Reports
Available online 15 March 2023, 112308