Vaccine Breakthrough Infections in Veterans Hospitalized with Coronavirus Infectious Disease-2019: A Case Series

Kim, Paul S.; Schildhouse, Richard J.; Saint, Sanjay; Bradley, Suzanne F.; Chensue, Stephen; Houchens, Nathan; Gupta, Ashwin

BACKGROUND: While SARS-CoV-2 vaccine breakthrough infections are expected, reporting on breakthrough infections requiring hospitalization remains limited. This observational case series report reviewed ten individuals hospitalized with vaccine breakthrough infections to identify patient risk factors and serologic responses upon admission. METHODS: Electronic medical records of BNT162b2 (Pfizer-BioNTech) or mRNA-1732 (Moderna) vaccinated patients admitted to VAAAHS with newly diagnosed COVID-19 between 15 March 2021 and 15 April 2021 were reviewed. Patient variables, COVID-19 lab testing including anti-S IgM, anti-N IgG antibodies, and hospital course were recorded. Based on lab testing, infections were defined as acute infection or resolving/resolved infection. RESULTS: Of the ten patients admitted with breakthrough infections, all were > 70 years of age with multiple comorbidities. Mean time between second vaccine dose and COVID-19 diagnosis was 49 days. In the seven individuals with acute infection, none had observed serologic response to mRNA vaccination, five developed severe disease, and one died. Three individuals had anti-N IgG antibodies and a high polymerase chain reaction cycle threshold (C(t)) value, suggesting resolving/resolved infection. CONCLUSIONS: Given the variability of vaccine breakthrough infections requiring hospitalization, serologic testing may impart clarity on timing of infection and disease prognosis. Individuals at risk of diminished response to vaccines and severe COVID-19 may also benefit from selective serologic testing after vaccination to guide risk mitigation strategies in a post-pandemic environment.