LAUSR

Background: A region-wide analysis of COVID-19 outcomes in New England has not been done. We aimed to characterize clinical, demographic, and vaccination status affecting COVID-19 clinical outcomes and describe viral epidemiology. Methods: Clinical variables of Veterans 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, non-psychiatric hospitalization, intensive care unit admission (ICU-care), and post-vaccination infection. We sequenced 754 whole viral genomes and 197 partial genomes. Results: Of 4,170 Veterans with COVID-19, 81% were White, 8% women, mean age was 60.1+17.7 years, and 2,399 became fully vaccinated. Overall, 19% Veterans needed hospitalization, 2.8% required ICU-care, and 3.7% died. Veterans with post-vaccination COVID-19 were older, with higher rates of tobacco/drug use, CKD, and malignancy, and 0.38% died. Among the unvaccinated, ICU-care and mortality correlated with age, while hospitalization correlated with age, male sex, black race, drug use, chronic heart disease, COPD, CKD, and chronic liver disease. Age, CKD, and alcohol use correlated with hospitalization in vaccinated patients. Most New England Veterans (>97%) were infected with B.1 sub-lineages with the D614G mutation in 2020 and early 2021. B.1.617.2 lineage (71%) predominated after July 2021, including the post-vaccination infections. Conclusion: In New England Veterans with mean age of 60 years, age and CKD significantly correlated with hospitalization regardless of vaccination-status. Age correlated with mortality and ICU-care among the unvaccinated. The Delta variant of SARS-CoV-2 (B.1.617.2) dominated post-vaccination infections.