Single vaccine approach could protect against coughs, colds and flus

US researchers report a nasal‑spray 'universal' vaccine that, in animal tests, kept lung immune cells on a heightened state and reduced viral passage for about three months; human trials are planned.

Researchers at Stanford describe a nasal spray they call a "universal" vaccine that produced broad protection in animals against multiple respiratory viruses and some bacteria. The spray appears to place lung macrophages on an "amber alert," a heightened readiness that reduced viral entry and altered immune responses. The team reported the effect lasted about three months in animal experiments and also reduced responses to a common house dust mite allergen. The researchers say this approach is a departure from traditional vaccines because it mimics immune-cell communication rather than training responses to a single pathogen. Key findings: - The vaccine was tested in animals and given as a nasal spray that left lung macrophages on an "amber alert," reportedly reducing viruses passing into the body by about 100-to-1,000-fold. - The heightened state of readiness lasted around three months in the animal experiments. - The team reported protection in animals against two bacterial species, Staphylococcus aureus and Acinetobacter baumannii. - The approach also appeared to reduce allergic responses to house dust mite in the experiments. - The researchers are planning human trials, including studies where vaccinated volunteers may be deliberately exposed to infection to assess protection. - Independent experts praised the work as exciting but cautioned that keeping the immune system in a heightened state could carry risks and that animal immune systems differ from humans. Summary: The study reports an experimental nasal spray that produced broad respiratory protection in animals and represents a different way to steer the immune system. Researchers plan human trials, including challenge studies, to determine whether the effect and its duration are reproduced in people, and safety questions about sustained immune activation remain under investigation.