Why Universal Covid-19 Vaccine Guidance Offers Stronger Protection Than High-risk-only Policies

Nine independent modeling teams show that maintaining a cosmopolitan COVID-19 vaccine argumentation yields accordant population-level benefits, reducing hospitalizations and deaths beyond high-risk-only strategies, moreover arsenic immune flight shifts nan timing of seasonal peaks.

Study: Scenario Projections of COVID-19 Burden successful nan US, 2024-2025. Image Credit: Ground Picture / Shutterstock

In a caller study published successful nan journal JAMA Network Open, researchers projected United States (US) COVID-19 hospitalizations and deaths for April 2024-April 2025 nether varying vaccination recommendations and immune flight assumptions, quantifying nan benefits of each strategy.

Background

One play tin still alteration thousands of lives: moreover successful 2023-2024, COVID-19 killed much Americans per hospitalization than seasonal influenza. Decisions by nan Advisory Committee connected Immunization Practices (ACIP) guideline nan Centers for Disease Control and Prevention (CDC) successful recommending who should beryllium vaccinated; however, nan improvement of variants and waning immunity support nan goalposts moving. Communities measurement convenience, cost, and fatigue against nan request for protection for older adults and group pinch underlying wellness conditions. Families and hospitals scheme for expected wintertime peaks, yet summertime surges tin still travel arsenic a surprise. Policymakers request numbers, not guesswork, to group wide aliases targeted guidance. Further investigation is required successful bid to comparison realistic vaccination pathways amid immune escape.

About nan study

The US Scenario Modeling Hub convened 9 independent teams to nutrient projections of COVID-19 hospitalizations and deaths from April 28, 2024, to April 26, 2025. Teams calibrated models to play infirmary admissions from nan National Healthcare Safety Network (NHSN) and deaths from nan National Center for Health Statistics (NCHS), utilizing routinely collected, anonymized surveillance. Six scenarios crossed 2 axes: immune flight astatine 20% per twelvemonth (low) aliases 50% per twelvemonth (high) for terrible acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and vaccine policy, 1) nary proposal (except for vaccine-naive children aging into eligibility astatine 6 months); 2) proposal only for high-risk groups (adults ≥65 years aliases individuals pinch underlying conditions); aliases 3) proposal for each persons aged ≥6 months.

Vaccines were reformulated to target circulating variants arsenic of June 15, 2024, and were expected to beryllium disposable arsenic of September 1, 2024, pinch 75% vaccine effectiveness (VE) against hospitalization astatine release. State- and age-specific sum was matched to observations from September 2023 to April 2024. Each squad specified infection-acquired immunity and waning. Individual projections were mixed via a trimmed linear sentiment excavation to shape an ensemble; prevented load nether vaccination scenarios was estimated utilizing meta-analytic methods. Uncertainty was summarized pinch 95% projection intervals (PI) and 95% assurance intervals (CI) wherever applicable.

Study results

Across each six scenarios, nan models estimated that nan U.S. COVID-19 load from April 2024 to April 2025 would beryllium akin to nan anterior year. Hospital admissions would stay beneath nan CDC's “high” level overall, expanding from precocious summertime into winter. In nan worst lawsuit (high immune flight and nary vaccine proposal beyond baseline pediatric vaccinations), nan projection was 931,000 hospitalizations (95% PI, 0.5-1.3 million) and 62,000 deaths (95% PI, 18,000-115,000) by April 26, 2025. In nan best-case script (low immune escape, pinch vaccination recommended for everyone), nan projection was 550,000 hospitalizations (95% PI, 296,000-832,000) and 42,000 deaths (95% PI, 13,000-72,000). Under assumptions astir apt for 2023-2024 (high immune flight pinch a cosmopolitan recommendation), projections were 814,000 hospitalizations (95% PI, 400,000-1.2 million) and 54,000 deaths (95% PI, 17,000-98,000). Adults aged ≥65 years accounted for 51%-62% of hospitalizations and 84%-87% of deaths.

Weekly Projections of COVID-19 Hospitalizations and Deaths successful nan United States During April 28, 2024, to April 26, 2025, Across 6 Scenarios of Immune Escape and Vaccination Recommendations. Ensemble projections are based connected 9 models, and humanities information are shown arsenic achromatic points. Unfilled information points correspond observed information aft nan projection period. National Healthcare Safety Network hospitalization information are shown only wherever nan reporting fraction was greater than 75%, highlighting nan spread successful reliable information during this clip (May 5, 2024, to November 2, 2024). Projection curves are colored based connected vaccine recommendations, pinch curves representing nan median of nan ensemble projection and shading showing nan 90% projection interval. Dashed lines bespeak nan Centers for Disease Control and Prevention thresholds for precocious and mean infirmary admittance levels (>20 and 10-20 play hospitalizations per 100,000, respectively).

Vaccination policies reduced nan load successful some immune-escape regimes. Recommending vaccination only for high-risk groups reduced hospitalizations by 11% (95% CI, 6%-16%) nether debased immune flight and by 8% (95% CI, 5%-11%) nether precocious immune escape; deaths fell by 13% (95% CI, 7%-18%) and 10% (95% CI, 6%-14%), respectively. Expanding to a cosmopolitan proposal yielded larger effects: hospitalizations fell by 15% (95% CI, 9%-21%) pinch debased immune flight and 11% (95% CI, 7%-16%) pinch precocious immune escape, while deaths decreased by 16% (95% CI, 10%-23%) and 13% (95% CI, 8%-18%). In absolute terms, nether precocious immune escape, vaccinating only high-risk groups averted 76,000 hospitalizations (95% CI, 34,000-118,000) and 7,000 deaths (95% CI, 3,000-11,000) versus nary recommendation. Extending recommendations to each ages accrued nan effect to 104,000 hospitalizations (95% CI, 55,000-153,000) and 9,000 deaths (95% CI, 4,000-14,000) averted.

Compared pinch a high-risk-only policy, a cosmopolitan argumentation provided further indirect protection to older adults, preventing astir 11,000 other hospitalizations and astir 1,000 other deaths successful those aged 65 years and older (representing a 3%-4% further simplification successful load for this group), reflecting community-level transmission benefits. Observed epidemiology diverged successful timing from projections: nan US knowledgeable a notable summertime 2024 activity peaking successful August, followed by a smaller wintertime 2025 peak. This shape aligns pinch higher effective immune flight successful summertime 2024 and little successful winter, differing from nan model's presumption of changeless yearly escape. Despite timing discrepancies, ensemble sum for play deaths was wrong expected ranges, and conclusions astir nan comparative benefits of broader vaccination remained stable. The study noted limitations, including nan imaginable for overestimating vaccine benefits if summertime 2024 immunity exceeded projections.

Conclusions

To summarize, scenario-based modeling suggests that reformulated COVID-19 vaccination remains a viable instrumentality to trim hospitalizations and deaths successful 2024-2025, peculiarly among adults aged 65 years and older and those pinch underlying conditions. While targeting high-risk groups unsocial yields important benefits, maintaining a cosmopolitan proposal offers additional, meaningful reductions, including indirect protection for older adults, nether some debased and precocious immune-escape conditions. Real-world version dynamics whitethorn displacement nan timing of peaks, but nan comparative advantages of broader vaccination persist. For households, clinics, and wellness systems readying nan respiratory microorganism season, cosmopolitan guidance tin prevention thousands much lives than narrower strategies.