Epidemiological characteristics of three SARS-CoV-2 variants of concern and implications for future COVID-19 pandemic outcomes

ABSTRACT

Three SARS-CoV-2 variants classified as variants of concern - B.1.1.7, B.1.351, and P.1 - have spread globally. To characterize their viral and epidemiological properties in support of public health planning, we develop and apply a model-inference system to estimate the changes in transmissibility and immune escape for each variant, based on case and mortality data from the country where each variant emerged. Accounting for under-detection of infection, disease seasonality, concurrent non-pharmaceutical interventions, and mass-vaccination, we estimate that B.1.1.7 has a 46.6% (95% CI 32.3 - 54.6%) increase in transmissibility but nominal immune escape from protection induced by prior wild-type infection; B.1.351 has a 32.4% (95% CI 14.6 - 48.0%) increase in transmissibility and 61.3% (95% CI 42.6 - 85.8%) immune escape; and P.1 has a 43.3% (95% CI 30.3 - 65.3%) increase in transmissibility and 52.5% (95% CI 0 - 75.8%) immune escape. Model simulations indicate that B.1.351 and P.1 could supplant B.1.1.7 dominance and lead to increased infections. Our findings highlight the importance of preventing the spread of B.1.351 and P.1, in addition to B.1.1.7, via continued preventive measures, prompt mass-vaccination of all populations, continued monitoring of vaccine efficacy, and possible updating of vaccine formulations to ensure high efficacy.