Benefits of Current COVID-19 Vaccines
The current 2024-2025 COVID-19 vaccines provide additional protection against severe COVID-19–associated illness and death, with the most substantial benefits being prevention of hospitalization and mortality, particularly in adults aged ≥65 years. 1
Primary Benefits by Outcome
Mortality and Severe Disease Prevention
The vaccines demonstrate robust protection against the outcomes that matter most—death and critical illness. Protection against severe outcomes (hospitalization, ICU admission, death) is significantly more durable than protection against infection alone, with vaccine effectiveness (VE) of 87.4% overall against severe disease from any variant 2. For critical illness specifically, VE remains at 69% within 7-59 days of vaccination and 32% even at 120-179 days post-vaccination 1.
The mortality impact is substantial: in 2023 alone, 44,059 COVID-19 deaths occurred in the United States, with the highest rates among adults ≥75 years 1. Economic modeling demonstrates vaccines are most cost-effective in adults ≥65 years, with an incremental cost-effectiveness ratio of $23,308 per quality-adjusted life year 1.
Hospitalization Prevention
Against COVID-19–associated hospitalization, VE among adults ≥18 years without immunocompromising conditions is 49% within 7-59 days of 2023-2024 vaccination, declining to 14% at 120-179 days 1. However, this waning protection can be restored with booster doses, which increase VE back to 87.9% and maintain it at 78.5% after 3 months 2.
Infection Prevention
Protection against symptomatic infection is more modest and variant-dependent. VE against symptomatic SARS-CoV-2 infection 60-119 days after vaccination was 58% for XBB-sublineage infection but only 37% for JN.1-sublineage infection 1. Against Omicron variants specifically, VE for infection is 26.1%, compared to 77% for pre-Omicron strains 2.
Key Population-Specific Benefits
High-Risk Groups
- Adults ≥75 years: Highest hospitalization and death rates, making vaccination most critical in this group 1
- Adults 65-74 years: Second-highest risk group for severe outcomes 1
- Infants <6 months: Third-highest hospitalization rates, though they cannot be directly vaccinated—maternal vaccination and household vaccination provide indirect protection 1
Children and Adolescents
Among hospitalized children ≤17 years with COVID-19 and no underlying conditions, 18% required ICU admission 1. Notably, 50% of hospitalized children had no underlying medical conditions, with this proportion being 75% in infants <6 months and 22% in adolescents 1. VE against medically attended COVID-19 is similar in children and adults 1.
Racial and Ethnic Disparities
Age-adjusted hospitalization rates during October 2023-May 2024 were highest among non-Hispanic American Indian/Alaska Native persons and non-Hispanic Black/African American persons 1, making vaccination particularly important for these populations.
Duration of Protection and Booster Importance
A critical caveat is that vaccine effectiveness wanes substantially over time, particularly for infection prevention. VE against infection decreases from 68.9% initially to 38.9% after 6 months 2. However, protection against severe outcomes declines less dramatically—after 6 months, vaccines still provide over 50% protection against severe outcomes from Omicron variants 2.
Booster doses are essential for maintaining protection, restoring VE to 76.4% against infection and 87.9% against severe outcomes 2. This underscores the importance of timely booster vaccination, especially for vulnerable populations.
Safety Profile
The safety profile remains favorable. Rates of prespecified adverse events (myocarditis, pericarditis, anaphylaxis) remain low for adults and adolescents and very low for infants and children 1. Two statistical signals were identified during 2023-2024 surveillance: Guillain-Barré syndrome in persons ≥65 years and ischemic stroke in adults ≥50 years 1. However, cumulative data have not provided clear and consistent evidence of actual safety problems, and any theoretical risks must be weighed against the substantial benefits in preventing COVID-19 and its serious complications, including stroke 1.
Broader Societal Value
Beyond individual protection, vaccines provide enormous societal economic value estimated at $5.0 trillion in the United States, primarily from reduction in depression prevalence ($1.9 trillion), gains to GDP ($1.4 trillion), and lives saved ($1.0 trillion) 3. Meta-analysis of controlled trials shows mRNA-based vaccines are most efficacious, with a pooled fold change of 0.08 (95% CI: 0.06-0.10) against COVID-19 incidence compared to placebo 4.
Current Recommendations
The Advisory Committee on Immunization Practices recommends 2024-2025 COVID-19 vaccination for all persons aged ≥6 months 1. The updated vaccines target currently circulating Omicron JN.1 lineage strains (JN.1 and KP.2), which have been predominant since winter 2023-2024 1.