The trial focuses on two common viral illnesses that affect older adults: Influenza infection and SARS‑CoV‑2 infection. It evaluates a new vaccine called mCombriax, which combines protection against both flu and COVID‑19 in a single injection. The vaccine uses messenger RNA (mRNA) to teach the body to recognize pieces of the flu viruses and the spike protein of the coronavirus. The study compares this combined vaccine with the usual practice of giving a high‑dose flu shot (Efluelda) and a COVID‑19 shot (Spikevax) at the same visit.
The purpose of the study is to determine whether the combined vaccine prevents doctor visits or hospital stays caused by flu or COVID‑19 as well as, or better than, the two separate shots. Participants aged 65 years or older will receive either the combined vaccine or the two separate vaccines on the same day and will be observed for several months. Any illness that leads to a medical appointment, emergency care, or hospitalization will be recorded to assess the vaccine’s effectiveness.



Denmark
Spain