Top 5 Takeaways

1. Higher Hospitalization Rates During Omicron: Weekly COVID-19–associated hospitalization rates peaked at 38.4 per 100,000 adults during Omicron predominance, compared to 15.5 during Delta predominance.
2. Impact of Vaccination Status: Unvaccinated adults were 12 times more likely to be hospitalized than those who received booster doses. Adults with only the primary series were three times more likely to be hospitalized than those with booster doses.
3. Racial Disparities: Non-Hispanic Black adults had the highest hospitalization rates during the Omicron period, nearly four times that of non-Hispanic White adults.
4. Vaccination Uptake: A larger proportion of Black adults were unvaccinated during the Omicron period compared to the Delta period, contributing to higher hospitalization rates.
5. Public Health Recommendations: Emphasizing the importance of staying up to date with COVID-19 vaccinations and implementing equitable vaccination strategies is crucial to reducing hospitalization rates.

Original Article Author and Citation

Corresponding Author

Christopher A. Taylor, iyq3@cdc.gov

Suggested Citation

Taylor CA, Whitaker M, Anglin O, et al. COVID-19–Associated Hospitalizations Among Adults During SARS-CoV-2 Delta and Omicron Variant Predominance, by Race/Ethnicity and Vaccination Status — COVID-NET, 14 States, July 2021–January 2022. MMWR Morb Mortal Wkly Rep 2022;71:466–473. DOI: http://dx.doi.org/10.15585/mmwr.mm7112e2

Summary

This report analyzes COVID-19–associated hospitalization rates among adults during the Delta and Omicron variant predominance periods, focusing on differences by race/ethnicity and vaccination status. The study found significantly higher hospitalization rates during the Omicron period, particularly among unvaccinated individuals and non-Hispanic Black adults. The data underscore the importance of booster doses in reducing hospitalization risks and highlight the need for equitable vaccination strategies.

Methods

Data from the COVID-19–Associated Hospitalization Surveillance Network (COVID-NET) were used to compare hospitalization rates during Delta (July 1–December 18, 2021) and Omicron (December 19, 2021–January 31, 2022) variant predominance. Hospitalization rates were calculated overall and stratified by race/ethnicity and vaccination status. Age-adjusted rates were derived using population estimates and state immunization information systems data. Clinical data were collected from a representative sample of hospitalized patients, and statistical analyses were conducted using SAS software.

Discussion

The analysis revealed that hospitalization rates increased significantly during the Omicron period, with the highest rates observed among unvaccinated adults and non-Hispanic Black adults. The findings suggest that the increased transmissibility of the Omicron variant, coupled with lower vaccination rates among Black adults, contributed to the observed disparities. The study emphasizes the need for targeted public health interventions to increase vaccination uptake and reduce hospitalization risks.

Conclusion

The study concludes that staying up to date with COVID-19 vaccinations, including booster doses, is essential to minimize hospitalization risks. Public health strategies should focus on equitable vaccine distribution and addressing barriers to vaccination among disproportionately affected groups, particularly non-Hispanic Black adults.

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