275. Evaluating the COVID-19 Pandemic in US Veterans: Transitioning from Delta to Omicron Variants

Abstract

Abstract Background During the COVID-19 pandemic many new variants of the SARS-CoV-2 virus have evolved. The omicron variant is the latest of concern and has numerous mutations in the spike protein (SP) which may alter COVID19 vaccine and therapeutic efficacy. We assessed whether COVID19 vaccination status would be protective among US Veterans (USV) who were diagnosed with SARS-CoV2 infection and performed an epidemiological analysis of this cohort. Methods A retrospective chart review was performed of USV with PCR confirmed SARS-CoV-2 infection who presented to Northport Veterans Affairs Medical Center between 11/1/2021 and 4/15/2022. Demographic information, vaccine status, medical comorbidities, SARS-CoV2 infection history, medical therapy receipt, need for hospitalization, SARS-COV-2 sequencing, and SP receptor-biding domain (RBD) IgG levels were reviewed. Two sample t-test and Chi-square analyses were performed. Results 605 USV were diagnosed with SARS-CoV2, median age was 62 years, 559 (92.4%) were male, 474 (78.3%) Caucasian and 77 (12.7%) Hispanic. 426 (70.4%) received at least one COVID19 vaccine dose, largely mRNA (n=400, 66.1%). Median time from vaccine dose to SARS-CoV2 diagnosis was 211 days (1-468). 26 (4.3%) USV had a previous history of SARS-CoV2 infection and 38 vaccinated USV had RBD-SP IgG titers (positive > 1 S/CO) at time of presentation, median 6.8 S/CO (0.06 to 71.21). Unvaccinated USV had a higher mean body mass index (31.0 vs. 30.0, p=0.04), and more commonly carried a diagnosis of COPD or asthma (20.0 vs. 11.8%, p=0.0005). A greater number of vaccinated USV utilized tobacco (44.2 vs 6.1%, p< 0.0001) or opioids (6.8 vs 1.1%, p< 0.0001). Unvaccinated USV more often required remdesivir (RDV) or dexamethasone (DEX) therapy (10.6 vs 6.6%, p=0.04). There was no difference in hospitalizations, monoclonal antibody use, or all-cause mortality between groups. Omicron BA.1 was first found on December 13, BA.2 on March 9 and final Delta variant on January 12. Demographic characteristics of the entire cohort, as well as by vaccination status Monthly SARS-CoV2 infections among US Veterans Monthly infections with delta and omicron SARS-CoV2 variants among vaccinated and unvaccinated US Veterans between 11/1/21 and 4/15/22 Daily SARS-CoV2 infections among US Veterans Daily infections with delta and omicron SARS-CoV2 variants among vaccinated and unvaccinated US Veterans between 11/1/21 and 4/15/22 Conclusion Omicron and Delta SARS-CoV-2 infections occurred in both vaccinated and unvaccinated USV, including among vaccinated persons with detectable neutralizing IgG titers. Unvaccinated USV were more likely to utilize RDV and DEX, suggesting severe infection was more common in this group. Disclosures All Authors: No reported disclosures.