ABSTRACT
Background. Vaccine hesitancy has been a major barrier during the COVID-19 pandemic. Surveys administered to assess vaccine acceptance have indicated several factors associated with individual's intention to receive COVID-19 vaccination, including risk perception, concern for side effects, political orientation, male sex, and having received an influenza (flu) vaccine. However, it is unknown whether these factors predict receipt of vaccination. We sought to determine factors that predicted COVID-19 vaccination in the Veterans Health Administration (VHA). Methods. We extracted COVID-19 vaccine status among Veterans with any VHA outpatient or inpatient visit from 12/01/2020 - 12/01/2021 from the VHA Corporate Data Warehouse. To ensure participants were engaged in ongoing VHA care, deceased individuals, and those with no visits in the prior year were excluded. We estimated association of proportion of years of VHA care in which influenza vaccine was received in the preceding 5 years with COVID-19 vaccination by logistic regression, adjusting for age, sex, and rurality of home address. Results. We identified 5,700,590 Veterans with outpatient/inpatient visits during the study period, with median age 66 years, of whom 5,131,617 (90%) were male. A total of 3,704,617 (65%) received at least 1 COVID-19 vaccination. Individuals who received influenza vaccination during each year in care had more than 4 times the odds of receiving COVID-19 vaccination than those who never received influenza vaccination. (Table 1). Age groups 50-64 years had twice the odds, and years 65-74 and over 75 had 3 times the odds of receiving COVID-19 vaccination versus those 18-49, while Veterans living in rural and highly rural areas had lower odds of receiving COVID-19 vaccination versus those in urban areas. Table 1. Multiple logistic regression analysis of predictors of COVID-19 vaccination among Veterans cared for in the Veterans Health Administration, December 2020 - December 2021. N=5,700,590 Abbreviations: aOR = Adjusted Odds Ratio, CI = Confidence Interval. 1 Proportion of years in care influenza vaccine received was calculated by dividing the total number of years a Veteran received influenza vaccine by the total number years the Veteran received care for the 5 years prior to the study time period. 2 VHA uses the Rural Urban Commuting Areas (RUCA) system to define rurality (RURAL VETERANS - Office of Rural Health (va.gov) Conclusion. Influenza vaccination on a regular basis (i.e., annually) was strongly linked to receipt of COVID-19 vaccination, indicating that prior influenza vaccine acceptance predicted COVID-19 vaccination. Public health efforts to reduce vaccine hesitancy (including targeted messaging to younger individuals, and those in rural areas) are important to increase vaccine acceptance in preparation for the next pandemic, as well as to decrease annual disease burden.
ABSTRACT
Background. A COVID-19 vaccine breakthrough infection is defined as SARSCoV-2 RNA or antigen detected ≥ 14 days after completion of a final vaccine dose. CDC's May 25 MMWR report of 10,262 vaccine breakthrough infections in the U.S. is likely an underestimate. Herein, we report Veterans Health Administration (VHA) breakthrough cases, focusing on hospitalizations and deaths. Methods. We extracted COVID-19 vaccine breakthrough infections tested between 1/19/2021 and 4/30/2021 from the VHA Corporate Data Warehouse (including screening tests). We reviewed medical records of cases who died and/or were hospitalized within 14 days of SARS-CoV-2 positive test for clinician documentation of conditions deemed high risk for COVID-19 and to confirm hospitalization or death was related to COVID-19. SARS-CoV-2 whole genome sequencing (Clear Labs platform) and antigen testing (Abbott BinaxNOW) from available patient samples were performed and Pangolin lineage determined. Results. 1,142 COVID-19 vaccine breakthrough infections were identified. 357/1,142 (31.3%) were hospitalized and/or died. 1,085 (95%) were male (Table 1), and median age was 72.5 years (74 years for hospitalized/deceased patients). COVID-19 infection contributed to hospitalization and/or death in 139 (38.9%) cases. The remaining 218 (61.1%) were hospitalized or died of causes apparently unrelated to COVID-19. Smoking and heart conditions were seen most frequently among hospitalized/ deceased breakthrough cases (Table 2). Variant B.1.1.7 was predominant, present in 17/27 (63%) total samples sequenced, and 13/21 (61.9%) hospitalized/deceased. (Table 3). Of 21 sequenced hospitalized/deceased cases, SARS-CoV-2 antigen positivity was present in 11 (52.4%). Conclusion. Compared to CDC reported breakthrough infections, VHA cases were more male, older, and hospitalized/died at higher frequency. Further study is needed to determine the contribution of specific underlying conditions, COVID-19 vaccine formulations and variants on hospitalization and death among COVID-19 vaccine breakthrough infections. Sequencing efforts for breakthrough cases should be intensified, particularly for those presenting with more severe infections.
ABSTRACT
Background. Veterans Health Administration's (VHA) large elderly population is at higher risk for influenza complications, including hospitalization and death. Herein we summarize VHA's national annual surveillance data for seasonal influenza activity and vaccinations. Methods. Influenza telephone triage, influenza-like-illness (ILI) encounters and antiviral prescriptions plus outpatient visits, laboratory testing, hospitalizations and deaths for influenza were obtained from VHA data sources (9/27/20-5/22/21) and compared to prior years and CDC FluView data. Influenza vaccinations were captured from 8/1/2020. Vaccination rates were calculated based on VHA users during the fiscal year. Results. Surveillance metrics are presented (Table). Vaccinations were decreased and ILI was below average (0.3%-0.7% per week). Activity was highest 2020 Weeks 46-47 but remained low the entire season with no distinct peak seen, matching national influenza activity (Fig. 1). Testing revealed 161 influenza positives from 440,553 tests performed (0.04%). Hospitalizations among laboratory-confirmed cases were similar to the prior season (16% vs 17%). Median length of stay (6 days) and deaths (17, 12%) were increased over prior seasons. Among 15 deaths where results were available, 4 had Influenza A, 10 had Influenza B and 1 had Influenza A+B. Nine were co-infected with COVID-19. Total influenza positives, outpatient visits, hospitalizations and antiviral use were extremely low compared to all prior season where national VHA data has been analyzed (Table, Fig. 2). Conclusion. Overall, influenza vaccination levels were decreased although percent receiving high-dose formulation was stable. Despite lower vaccination rates, the 2020-21 influenza season was of historically low activity, even with markedly increased testing performed in the setting of multiplex tests for influenza with COVID-19. Deaths were primarily seen with Influenza B and among those co-infected with COVID-19. This may also have contributed to increased length of stay. VHA influenza activity continues to track closely with national CDC data and may have been impacted by mitigation measures used to contain COVID-19, which were likely effective in curbing influenza activity.