Unveiling the Disproportionate Impact on the Unvaccinated During COVID-19 Waves
The COVID-19 pandemic has consistently presented challenges, with new variants emerging and evolving. Understanding the comparative risks faced by unvaccinated individuals versus those vaccinated is crucial for public health strategies. This report, based on data from 25 U.S. jurisdictions, delves into the critical question: what percent of unvaccinated individuals died compared to vaccinated individuals during the Delta and Omicron variant emergence periods? Our analysis, grounded in a robust CDC study, reveals significant disparities in both COVID-19 case incidence and, most critically, death rates, underscoring the protective power of vaccination.
Key Findings from the CDC Report: Mortality Disparities Highlighted
This comprehensive analysis period, spanning from April to December 2021, encompassed the pre-Delta, Delta emergence, Delta predominance, and the initial emergence of the Omicron variant. The data clearly demonstrates a stark contrast in outcomes based on vaccination status, particularly when examining death rates.
Dramatic Differences in Death Rates: Unvaccinated at Higher Risk
Across all periods studied, unvaccinated individuals faced substantially higher death rates compared to their fully vaccinated counterparts. During the Delta predominance period (July-November 2021), the average weekly death rate for unvaccinated individuals reached 11.4 per 100,000 population, while for fully vaccinated individuals, it was a mere 0.7 per 100,000. This translates to unvaccinated persons having approximately 16 times the risk of death compared to fully vaccinated individuals during this period.
Even during the Omicron emergence in December 2021, although death rate calculations were limited to the first week of December due to reporting lags, the trend persisted. The death rate for unvaccinated individuals was significantly higher (9.7 per 100,000) than for fully vaccinated persons (0.5 per 100,000).
Booster Doses Amplify Protection Against Death
The study further examined the impact of booster doses, revealing even greater protection against death for those who received them. During October-November 2021, the death rate among fully vaccinated individuals with a booster dose was remarkably low at 0.1 per 100,000 population. In stark contrast, the rate for unvaccinated individuals was 7.8 per 100,000. This implies that unvaccinated individuals faced a staggering 53 times greater risk of death compared to fully vaccinated and boosted individuals during this period.
Image alt text: Visual representation of COVID-19 protection through vaccination, illustrating lower incidence and death rates for vaccinated individuals, especially with boosters, during Omicron emergence, reinforcing vaccine effectiveness.
Age-Related Disparities in Mortality and Booster Benefits
The benefits of vaccination, and particularly booster doses, were most pronounced in older age groups. For individuals aged 65 years and older during October-November 2021, the death rate for unvaccinated individuals was 33.4 per 100,000, compared to just 3.1 for fully vaccinated individuals without a booster, and an incredibly low 0.5 for those with a booster. This demonstrates the critical role of booster shots in enhancing protection against severe outcomes, particularly for vulnerable older populations.
Similarly, for the 50-64 age group, the death rate for unvaccinated individuals (7.3 per 100,000) was significantly higher than both fully vaccinated groups (0.4 without booster, 0.2 with booster). These age-specific data points underscore the importance of targeted vaccination and booster campaigns for older adults to minimize severe illness and death.
Variant Impact: Delta and Omicron and the Unchanging Message of Vaccination
While the emergence of the Delta and Omicron variants brought changes in case incidence and vaccine effectiveness against infection, the protective effect against severe disease and death remained robust, especially with booster doses. The data indicates that even as variants evolved, the fundamental principle of vaccination as a shield against severe outcomes, including death, held firm. The consistent and significant difference in death rates between unvaccinated and vaccinated groups across different variant periods reinforces the enduring value of COVID-19 vaccination.
Detailed Data: Incidence Rate Ratios and Vaccine Effectiveness
To further illustrate the disparity, the study utilized Incidence Rate Ratios (IRRs). An IRR compares the incidence rate in one group to another. In this context, it compares the incidence rate of cases or deaths in unvaccinated individuals to vaccinated individuals. A higher IRR signifies a greater risk for the unvaccinated group.
Table 1: COVID-19 Cases and Deaths – Unvaccinated vs. Fully Vaccinated
| Event/Variant Period | Unvaccinated Persons | Fully Vaccinated Persons | Average Weekly IRR (95% CI) |
|---|---|---|---|
| COVID-19 Cases | |||
| Pre-Delta (April–May 2021) | 1,006,686 | 48,111 | 13.9 (12.4–15.5) |
| Delta Emergence (June 2021) | 196,988 | 30,317 | 8.7 (6.1–12.4) |
| Delta Predominance (Jul-Nov 2021) | 4,546,682 | 1,862,090 | 5.1 (4.3–6.0) |
| Omicron Emergence (Dec 2021) | 1,061,684 | 925,999 | 3.1 (1.7–5.8) |
| COVID-19–Associated Deaths | |||
| Pre-Delta (April–May 2021) | 11,047 | 1,016 | 21.9 (17.8–26.8) |
| Delta Emergence (June 2021) | 3,107 | 556 | 16.4 (13.2–20.4) |
| Delta Predominance (Jul-Nov 2021) | 78,256 | 20,313 | 16.3 (13.8–19.3) |
| Omicron Emergence (Dec 2021)* | 2,230 | 682 | NC |
*Note: Omicron death data for December is limited to the first week.
Source: CDC MMWR Report
This table clearly demonstrates the consistently higher IRR for deaths compared to cases, highlighting the stronger protective effect of vaccines against severe outcomes. For instance, during the Delta predominance period, while the case IRR was 5.1, the death IRR was significantly higher at 16.3.
Table 2: Unvaccinated vs. Fully Vaccinated with and without Boosters – Cases and Deaths (Oct-Dec 2021)
| Event/Time | Unvaccinated | Fully Vaccinated (No Booster) | Fully Vaccinated (With Booster) |
|---|---|---|---|
| COVID-19 Cases (Oct-Nov) | |||
| Overall IRR | Ref | 4.0 (3.6–4.4) | 13.9 (12.2–15.9) |
| COVID-19 Cases (Dec) | |||
| Overall IRR | Ref | 2.8 (1.6–5.2) | 4.9 (2.7–8.9) |
| COVID-19 Deaths (Oct-Nov) | |||
| Overall IRR | Ref | 12.7 (11.6–13.8) | 53.2 (37.5–75.4) |
Source: CDC MMWR Report
Note: IRR is calculated as incidence in unvaccinated divided by incidence in vaccinated groups.
Table 2 further breaks down the data by booster dose status during the Delta predominance and Omicron emergence periods. The IRRs for deaths are strikingly high, especially when comparing unvaccinated individuals to those fully vaccinated and boosted. The IRR of 53.2 for deaths when comparing unvaccinated to boosted individuals during October-November underscores the dramatic reduction in mortality risk conferred by booster doses.
Image alt text: Line graph depicting COVID-19 case and death incidence trends from April to December 2021, contrasting unvaccinated, fully vaccinated, and boosted groups, overlaid with variant proportions, demonstrating the sustained higher rates among unvaccinated individuals and the protective impact of boosters.
Discussion: The Consistent Message of Vaccine Protection
The data presented in this CDC report provides compelling evidence of the continued protection offered by COVID-19 vaccines against severe illness and death, even during the emergence of new variants like Delta and Omicron. While vaccine effectiveness against infection may have decreased with new variants and waning immunity, the protection against death remained remarkably strong, especially for those who received booster doses.
It is important to acknowledge the study’s limitations, including potential data lags, ecological study design, and the inability to fully control for all confounding factors. However, the consistent trends observed across a large dataset from 25 U.S. jurisdictions strongly suggest a causal relationship between vaccination and reduced risk of severe outcomes, including death.
Conclusion: Stay Up-to-Date with COVID-19 Vaccination
In conclusion, this analysis reinforces a critical public health message: COVID-19 vaccination is a powerful tool for reducing the risk of severe illness and death. The data unequivocally demonstrates that a significantly higher percentage of unvaccinated individuals died compared to vaccinated individuals during both the Delta and Omicron waves. Booster doses further enhance this protection, particularly against mortality.
For optimal protection against COVID-19, including emerging variants, it is imperative that all eligible individuals stay up to date with their COVID-19 vaccinations, including recommended booster doses. Consult public health guidelines and healthcare providers for the most current recommendations and to make informed decisions about your health and the health of your community.
References
Johnson AG, Amin AB, Ali AR, et al. COVID-19 Incidence and Death Rates Among Unvaccinated and Fully Vaccinated Adults with and Without Booster Doses During Periods of Delta and Omicron Variant Emergence — 25 U.S. Jurisdictions, April 4–December 25, 2021. MMWR Morb Mortal Wkly Rep 2022;71:132–138. DOI: http://dx.doi.org/10.15585/mmwr.mm7104e2.
