Clinical and virologic factors associated with outcomes of COVID-19 before and after vaccination among Veterans: Retrospective analysis from six New England states.

We aimed to characterize clinical and demographic factors affecting clinical outcomes of COVID-19 and describe viral epidemiology among unvaccinated Veterans in New England. Veterans infected with COVID-19 in Veterans Administration healthcare systems in six New England states from April 8, 2020, to September 2, 2021, were correlated with outcomes of 30-day mortality, nonpsychiatric hospitalization, and intensive care unit admission (ICU-care). We sequenced 827 viral genomes. Of 3950 Veterans with COVID-19 before full vaccination, 81% were White, 8% were women, and the mean age was 60 years. Overall, 19% of Veterans required hospitalization, 2.8% required ICU care, and 4.9% died. In this largely male and older cohort, poor outcomes correlated with increasing age. Most New England Veterans (>97%) were infected with B.1 sublineages with the D614G mutation in 2020 and early 2021. B.1.617.2 lineage (68%) predominated after July 2021.