One Shot Could Shield You From Flu, COVID‑19 and RSV, Early Study Shows

Combined shot offers protection against three major respiratory viruses

A novel vaccine formulation that merges protection against influenza, SARS‑CoV‑2 and respiratory syncytial virus (RSV) has demonstrated robust immune responses in pre‑clinical studies.

Pre‑clinical trials reveal broad immunity

In research published in Science Advances, scientists reported that a single‑dose vaccine induced protective antibodies in mice, ferrets and cotton rats against all three pathogens. The immune profiles were on par with those generated by single‑target vaccines, indicating that the combined approach did not compromise efficacy.

Rationale behind a three‑in‑one vaccine

Since 2022, health systems have grappled with a “tripledemic” of flu, COVID‑19 and RSV, which together accounted for roughly one million hospital admissions in the United States during the 2023–2024 season. Vaccination rates remain low, especially among seniors: only about a third of those 75 and older had received a flu shot by November 2024, with similar shortfalls for COVID‑19 and RSV vaccines.

Co‑author Bruce Davidson, a research associate professor of anesthesiology at the University at Buffalo (UB), noted that consolidating the three recommended shots into a single annual injection could simplify logistics and boost coverage.

CoPoP platform underpins the multi‑antigen design

The vaccine leverages UB’s cobalt‑porphyrin (CoPoP) nanoparticle technology, a decade‑old platform that presents viral proteins on tiny lipid‑coated spheres. By exploiting histidine tags on the proteins, researchers anchor them to the cobalt core, creating a stable complex that trains the immune system without using genetic material.

For the current study, five proteins—three from influenza strains and one each from SARS‑CoV‑2 and RSV—were incorporated into the particle matrix. The formulation was further enhanced with adjuvants PHAD and QS‑21 to amplify the immune response.

“The flexibility of CoPoP lets us load multiple antigens simultaneously,” explained Jonathan Lovell, the study’s corresponding author and a professor of biomedical engineering at UB.

Safety and future directions

Investigators observed no signs of immune interference, where one component might suppress the response to another. Nevertheless, they caution that additional experiments are required to explore subtle interactions that could emerge under varied dosing regimens.

Lovell envisions expanding the platform to cover an even broader spectrum of respiratory pathogens, potentially streamlining seasonal vaccination strategies.