One nasal spray vaccine may shield against colds, flu and allergies: Study

Early findings show a nasal spray vaccine may strengthen lung immunity against diverse pathogens, though human trials are still needed

Each year, seasonal waves of coughs, colds and flu sweep through homes, schools and offices, and although vaccines help against specific viruses, new strains and unexpected pathogens continue to emerge. Now, a new study suggests that a single nasal spray vaccine might offer protection against a wide range of respiratory viruses, bacterial lung infections and even allergies, which could transform how we prepare for seasonal illness.

 

The study, titled 'Mucosal vaccination in mice provides protection from diverse respiratory pathogens through innate and adaptive immunity', published in the journal Science, explores an experimental approach that works very differently from conventional vaccines.

 

What did the study find?

 

The research was led by scientists at Stanford Medicine, and collaborators from Emory University School of Medicine, the University of North Carolina at Chapel Hill, Utah State University and the University of Arizona also contributed to the study.

 

Researchers tested the experimental vaccine in mice. According to the findings, vaccinated mice showed protection against multiple respiratory threats. Key observations included:

 

• Protection against SARS-CoV-2 and other coronaviruses
• Defence against bacterial pathogens such as Staphylococcus aureus and Acinetobacter baumannii
• Reduced allergic inflammation triggered by house dust mite exposure
• Broad lung protection lasting at least three months

 

This wide-ranging effect suggests that the immune system in the lungs had been primed to respond more effectively to different invaders, rather than just one.

 

Professor Bali Pulendran, senior author of the study, noted that the nasal vaccine appeared to place immune cells in the lungs in a heightened state of alert, which meant they could react faster and more effectively when faced with infection.

 

How is this vaccine different from traditional ones?

 

Most vaccines train the immune system to recognise one particular virus or bacterium, and they do this by exposing the body to a harmless part of that specific pathogen. This strategy has saved millions of lives, but it also means that protection is usually narrow and must be updated when viruses evolve.

 

In contrast, the research team tested a nasal spray designed to boost the lungs’ broad defence systems, rather than targeting a single microbe. The vaccine works at the mucosal surface of the nose and lungs, which is where many respiratory infections begin, and it stimulates both the innate immune system and the adaptive immune response.

 

Professor Pulendran explained that the approach represents a significant departure from classical vaccination because it focuses on strengthening general immune readiness rather than aiming at one specific virus.

 

How does it work in the body?

 

Instead of introducing a fragment of a virus, the nasal spray mimics the danger signals that typically appear during infection. These signals activate immune cells such as macrophages and other frontline defenders in the lungs, and also enhance longer-term adaptive responses.

 

Since, the vaccine is delivered directly into the nose, it strengthens immunity at the site where respiratory viruses first enter the body. This is important because many existing vaccines are injected into the muscle, and while they provide strong systemic protection, they may not generate the same level of local immunity.

 

Experts believe this local boost could be crucial. Professor Daniela Ferreira, a respiratory infection specialist at the University of Oxford, told the BBC that if the results translate to humans, the approach could change how we protect people from common respiratory infections.

 

Could this also help with allergies?

 

One of the findings was that the vaccine reduced allergic inflammation in mice exposed to house dust mites, which are a common trigger for asthma and allergic rhinitis (also known as hay fever).

 

The researchers suggest that by recalibrating immune responses in the lungs, the nasal spray may prevent exaggerated inflammatory reactions. While this aspect remains in very early stages, it raises the possibility that a single intervention could both protect against infection and dampen harmful allergic responses.

 

From lab to clinic: What comes next?

 

Despite the promising data, this research is still at an early stage as it has only been tested in animals. Human immune systems are more complex, and responses can differ significantly from those seen in mice. Experts emphasise that clinical trials in people are essential to determine safety, optimal dosing and duration of protection.

 

However, if future trials confirm these findings, a universal nasal spray vaccine could complement existing targeted vaccines, provide rapid protection at the start of outbreaks and reduce the overall burden of respiratory illness.     

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This report is for informational purposes only and is not a substitute for professional medical advice.