Health impact of a combined COVID-19-influenza mRNA vaccine in older and high-risk Dutch adults

Background

Combined COVID-19 and influenza vaccines may increase protection against respiratory disease, notably by improving COVID-19 uptake, which lags behind influenza coverage globally. Data on the effectiveness of mRNA-1083 against both diseases are promising. We evaluate the health impact of introducing mRNA-1083 into the Dutch vaccination program versus separate administration of standard-dose influenza and current COVID-19 vaccines.

Methods

A static decision tree model evaluated the health impact of annual mRNA-1083 vaccination. The target population included adults ≥60 years and high-risk individuals ≥50 years. Vaccine effectiveness was derived from clinical trial data and a meta-analysis; coverage followed Dutch influenza vaccination levels. Incidence was derived from primary care surveillance (respiratory season 2023/24). Hospitalizations and in-hospital mortality were obtained from national ICD-10-coded hospital records (2023). Nursing home mortality was informed by a Dutch study on deaths associated with LRTI, ILI, and COVID-19. Outcomes were expressed as averted cases per category.

Results

Incorporating mRNA-1083 substantially reduces disease burden versus the current strategy. For COVID-19, this corresponds to 13,331 (10,527 - 15,693) GP visits, 4,194 (3,541 - 4,698) hospitalizations, and 1,297 (1,104 - 1,445) deaths averted in a full year. The higher effectiveness of the influenza component in the combined vaccine further prevents a total of 12,222 (-1,203 - 22,103) GP visits, 3,372 (242 - 6,285) cardiorespiratory hospitalizations, and 1,194 (457 - 1,851) deaths in the base-case scenario.

Conclusions

mRNA-1083 for older adults and high-risk groups could substantially reduce disease burden due to respiratory infections in the Netherlands. These findings support the value of combination vaccines for mitigating seasonal respiratory disease.

Key messages

• The use of a combined COVID‑19–influenza mRNA vaccine is projected to substantially reduce the burden of seasonal respiratory disease.

• mRNA‑1083 could avert ∼25,500 GP visits, ∼7,600 hospitalisations, and ∼2,500 deaths from COVID‑19 and influenza among older and high‑risk adults in the Netherlands.