Universal vaccine could protect against colds, flu and COVID.

A mouse study published in Science reports a nasal 'universal' vaccine that primed lung immune cells and protected mice against multiple respiratory viruses for up to three months; human safety and effectiveness remain unproven.

A new vaccine approach aims to raise broad frontline defenses in the nose and lungs rather than training immunity to a single virus. Researchers tested a nasal formulation in mice that mimics signals the body makes when under microbial attack. In the study, the vaccine primed alveolar macrophages and T cells in mucosal tissues and provided protection against several respiratory viruses for up to three months. Scientists emphasize that results in mice do not guarantee the same effects in people and that safety must be established. Key findings: - The study was carried out in mice and published in the journal Science. - The vaccine is delivered nasally to target mucosal surfaces in the nose, throat and lungs. - It appears to boost communication between alveolar macrophages and T cells, producing faster pathogen clearance in mice. - Protection in mice lasted up to about three months, and the vaccine also reduced some allergic responses in the animals. - Researchers say controlled human infection studies and other safety trials are the next critical steps, and safety in older people is an open question. - The study's senior author estimated a best-case human availability timeline of about five to seven years, but noted that progress depends on how early human trials perform. Summary: If similar effects occur in people, a broadly acting mucosal vaccine might reduce the need for separate seasonal shots against RNA respiratory viruses and could offer an early layer of defence in future outbreaks. Demonstrating safety, determining duration of protection in humans, and testing effectiveness across age groups are the immediate priorities. Progress and timing remain uncertain and will depend on the outcomes of human trials.