American researchers say that a single nasal spray vaccine can protect against all types of coughs, colds, and flu, as well as bacterial lung infections, and even alleviate allergic reactions, UNN reports, citing the BBC.
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A Stanford University team tested their "universal vaccine" on animals and still needs to conduct human clinical trials.
Their approach marks a "radical departure" from how vaccines have been developed for over 200 years, they say.
Experts in the field said the research was "really exciting," despite being at an early stage, and could be an "important step forward."
Modern vaccines train the body to fight a single infection. A measles vaccine only protects against measles, and a chickenpox vaccine only protects against chickenpox. This is how immunization has worked since Edward Jenner pioneered vaccine development in the late 18th century.
The approach, described in the journal Science, does not train the immune system. Instead, it mimics how immune cells communicate with each other, the publication writes.
The vaccine is administered as a nasal spray and causes white blood cells in the lungs—called macrophages—to be in a state of "amber alert" and ready for action, no matter what infection tries to enter the body, the publication writes.
The effect lasted about three months in animal experiments.
Researchers showed that this heightened state of readiness resulted in a 100-1000-fold reduction in the number of viruses entering the body through the lungs.
And for those that did manage to slip through, the rest of the immune system was "tuned up, ready to fend them off at a furious pace," said Professor Bali Pulendran, Professor of Microbiology and Immunology at Stanford.
The team showed that the vaccine also protected against two types of bacteria – Staphylococcus aureus and Acinetobacter baumannii.
Pulendran told the BBC: "This vaccine, which we call a universal vaccine, elicits a much broader response that protects not only against the flu virus, not only against the Covid virus, not only against the cold virus, but against virtually all viruses and as many different bacteria as we have tested, and even against allergens."
"The principle by which this vaccine works is radically different from the principle by which all vaccines have worked so far," she noted.
The way it directs the immune system to fight infection also appears to reduce the response to dust mite allergens, which are a trigger for allergic asthma, the publication notes.
"This is a really exciting study," said Professor Daniela Ferreira, Professor of Vaccinology at the University of Oxford, who was not involved in the research.
She said it could "change how we protect people from common coughs, colds, and other respiratory infections" if the results are confirmed in human studies.
However, many questions still remain to be answered, the publication writes.
The vaccine was administered as a nasal spray in experiments, but it may need to be inhaled through a nebulizer to reach the depths of human lungs.
It is unknown whether the same effect can be achieved in humans, or how long the immune system will remain in a state of "amber alert." There are differences in the immune systems of mice and humans, in particular, our immunity is formed by decades of infections.
Therefore, researchers are planning trials where one person is vaccinated and then intentionally infected to see how their body copes, the publication writes.
There may also be consequences of re-tuning the immune system beyond its normal state, which raises questions about immune disorders, the publication notes.
Jonathan Ball, Professor of Molecular Virology at the Liverpool School of Tropical Medicine, said the work was undoubtedly "interesting" but cautioned: "We need to make sure that keeping the body on 'high alert' doesn't lead to friendly fire, where a hyper-ready immune system accidentally causes unwanted side effects."
The research team in the US does not believe that the immune system should be constantly boosted and believes that such a vaccine should be used to supplement, not replace, existing vaccines.