Trajectory of Growth of SARS-CoV-2 Variants in Houston, Texas, January through May 2021 Based on 12,476 Genome Sequences

Abstract

Genetic variants of the SARS-CoV-2 virus are of substantial concern because they can detrimentally alter the trajectory of the ongoing pandemic, and disease course in individual patients. Here we report genome sequences from 11,568 COVID-19 patients in the Houston Methodist healthcare system dispersed throughout the metroplex that were diagnosed from January 1, 2021 through April 30, 2021. This sample represents 94% of Houston Methodist cases and 4.6% of all reported cases in the metropolitan area during this period. The SARS-CoV-2 variant designated UK B.1.1.7 increased very rapidly, and now causes 75%-90% of all new cases in the Houston area. Five of the 2,543 B.1.1.7 genomes had an E484K change in spike protein. Compared with non-B.1.1.7 patients, individuals infected with B.1.1.7 had a significantly lower cycle threshold value (considered to be a proxy for higher virus load) and higher rate of hospitalization. Other variants (e.g., B.1.429, B.1.427, P.1, P.2, and R.1) also increased rapidly in frequency, although the magnitude was less than for B.1.1.7. We also identified 42 patients with a recently described R.1 variant that has an E484K amino acid replacement, and seven patients with the B.1.617 "India" variants. In the aggregate, our study shows the occurrence of a diverse array of concerning SARS-CoV-2 variants circulating in a major metropolitan area, documents B.1.1.7 as the major cause of new cases in Houston and heralds the arrival and spread of B.1.617 variants in the metroplex.