A universal vaccine for humans against cold, flu, COVID and allergies has moved a significant step closer following a study using mice, scientists say.
The vaccine, which could be given as a nasal spray, has been developed by experts at Stanford Medicine in the US.
It may protect against a wide range of respiratory viruses, bacteria and allergy triggers, they claimed.
Scientists said the vaccine offered broad protection in the lungs of mice for several months.
Vaccinated animals were protected against COVID and other coronaviruses, Staph (which can infect the skin and cause sepsis), Acinetobacter baumannii (which can cause infections in the blood, urinary tract, lungs or wounds), and house dust mites.
This form of vaccine, if translated into humans, could replace multiple jabs every year for winter respiratory infections.
It also has the potential to work against new pandemic bugs.
Lead author Dr Bali Pulendran, from Stanford Medicine, said: “I think what we have is a universal vaccine against diverse respiratory threats.
“Imagine getting a nasal spray in the fall months that protects you from all respiratory viruses including COVID-19, influenza, respiratory syncytial virus and the common cold, as well as bacterial pneumonia and early spring allergens.
“That would transform medical practice.”
The researchers are now hoping to trial the vaccine on humans.
A safety trial would be followed by a larger trial in which patients are exposed to infections.
Dr Pulendran thinks two doses of the nasal spray would be sufficient to provide protection in people.
He estimates the vaccine might be available in five to seven years, if there is enough funding.
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In the study, a drop of the vaccine was administered to mice through their noses.
The vaccine offered protection for several months against various forms of viral infections, bacterial respiratory infections and house dust mites – a common trigger for allergic asthma.
Researchers were able to demonstrate protection in mice and showed that helpful T cells in the lungs, which are working against pathogens, could send signals to the body’s innate immune cells to keep them active.
Instead of trying to mimic part of a pathogen, the vaccine mimics the signals that immune cells use to communicate with each other during an infection.
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Professor Brendan Wren, from the London School of Hygiene and Tropical Medicine, said it was a “potentially promising approach that could have wide applications and implications” but he cautioned it was “early days”.
He added there was “a long road to go before we’ll know if this approach produces a safe and effective vaccine for humans”.
The new vaccine, known for now as GLA-3M-052-LS+OVA, mimics the T cell signals that directly stimulate innate immune cells in the lungs.
It also contains a harmless antigen that recruits T cells into the lungs to help the body fend off pathogens for weeks or months.
The study was published in the journal Science.
