Trends in Disparities in COVID Hospitalizations Among Community-dwelling Residents of Two Counties in Connecticut, Before and After Vaccine Introduction, March 2020-September 2021

Background: Prior to the introduction of vaccines, COVID-19 hospitalizations of non-institutionalized persons in Connecticut disproportionately affected communities of color and individuals of low socioeconomic status (SES). Whether the magnitude of these disparities changed 7-9 months after vaccine rollout during the Delta wave is not well documented.

Methods: All initially hospitalized patients with laboratory-confirmed COVID-19 during July-September 2021 were obtained from the Connecticut COVID-19-Associated Hospitalization Surveillance Network database, including patients' geocoded residential addresses. Census tract measures of poverty and crowding were determined by linking geocoded residential addresses to the 2014-2018 American Community Survey. Age-adjusted incidence and relative rates of COVID-19 hospitalization were calculated and compared with those from July to December 2020. Vaccination levels by age and race/ethnicity at the beginning and end of the study period were obtained from Connecticut's COVID vaccine registry, and age-adjusted average values were determined.

Results: There were 708 COVID-19 hospitalizations among community residents of the two counties, July-September 2021. Age-adjusted incidence was the highest among non-Hispanic Blacks and Hispanic/Latinx compared with non-Hispanic Whites (RR 4.10 [95% CI 3.41-4.94] and 3.47 [95% CI 2.89-4.16]). Although RR decreased significantly among Hispanic/Latinx and among the lowest SES groups, it increased among non-Hispanic Blacks (from RR 3.2 [95% CI 2.83-3.32] to RR 4.10). Average age-adjusted vaccination rates among those ≥12 years were the lowest among non-Hispanic Blacks compared with Hispanic/Latinx and non-Hispanic Whites (50.6% vs. 64.7% and 66.6%).

Conclusions: Although racial/ethnic and SES disparities in COVID-19 hospitalization have mostly decreased over time, disparities among non-Hispanic Blacks increased, possibly due to differences in vaccination rates.