US researchers say a single nasal spray vaccine could one day protect people from coughs, colds, flu, bacterial lung infections and even help reduce allergies. Scientists at Stanford University have tested this “universal vaccine” in animals, but human clinical trials are still needed.
The researchers describe their method as a major change from how vaccines have been developed for more than 200 years. Experts who reviewed the study called it very exciting, although they noted that it is still in the early stages and requires further testing.
Traditional vaccines train the immune system to fight one specific infection. For example, a measles vaccine protects only against measles, and a chickenpox vaccine protects only against chickenpox. This has been the standard approach since Edward Jenner first introduced vaccines in the late 18th century.
However, the new approach, published in the journal Science, does not directly train the immune system to target a single disease. Instead, it copies the way immune cells communicate with each other. The vaccine is given as a nasal spray and prepares certain white blood cells in the lungs, known as macrophages, to stay alert and ready to respond quickly to any infection.
In animal studies, this effect lasted for about three months. Researchers found that this state of readiness reduced the number of viruses entering the lungs and spreading through the body by 100 to 1,000 times. Even when some viruses managed to get through, the rest of the immune system responded very quickly.
Professor Bali Pulendran, a microbiology and immunology expert at Stanford, said the vaccine produces a much broader protective response than current vaccines. According to him, it offers protection not only against flu, Covid-19, and common cold viruses, but also against many other viruses, several types of bacteria tested so far, and even allergens.
The team also showed that the vaccine protected against two bacteria, Staphylococcus aureus and Acinetobacter baumannii. In addition, the way the vaccine guides the immune system appears to reduce reactions to house dust mite allergens, which often trigger allergic asthma.
Professor Daniela Ferreira from the University of Oxford, who was not involved in the research, described the findings as very exciting. She said that if future human trials confirm these results, the vaccine could change how people are protected from common respiratory infections. She also praised the study for clearly explaining how this new type of vaccine works and said it could become a major step forward in reducing the heavy burden caused by these infections.
