Stanford nasal spray vaccine protects against viruses, bacteria in animal tests

Universal nasal spray vaccine shows promise in animals

Researchers at Stanford University have developed a nasal spray vaccine that, in animal studies, protected against a wide range of viruses, bacteria, and even allergens. The team calls the approach a "radical departure" from over two centuries of vaccine design.

Their findings, published in the journal Science, show the vaccine put lung immune cells on high alert for about three months. This led to a 100-to-1,000-fold reduction in viruses penetrating the lungs in mice.

How the new vaccine works

Traditional vaccines train the immune system to recognize and fight one specific pathogen, like measles or chickenpox. This new method does not target a single germ.

Instead, it mimics the way immune cells communicate. The spray leaves white blood cells in the lungs, called macrophages, in a heightened state of readiness to attack any incoming infection.

"This vaccine elicits a far broader response that is protective against not just the flu virus, not just the Covid virus, not just the common cold virus, but against virtually all viruses, and as many different bacteria as we've tested," said lead researcher Prof Bali Pulendran.

Experts call the research "really exciting"

Independent experts praised the study while noting it is at an early stage. "This is a really exciting piece of research," said Prof Daniela Ferreira, a vaccinology professor at the University of Oxford who was not involved.

She said it could "change how we protect people from common coughs, colds and other respiratory infections" if human trials succeed. The research also showed the vaccine reduced the immune response to house dust mite allergens, a trigger for allergic asthma.

The study demonstrated protection against several threats in animals:

• Multiple viruses, including flu and common cold viruses
• Two drug-resistant bacteria: Staphylococcus aureus and Acinetobacter baumannii
• Allergens that cause allergic asthma

Major questions remain before human use

Significant hurdles must be cleared before this could become a usable vaccine. The effect must be proven in people, and the duration of protection is unknown. Human immune systems are more complex and shaped by a lifetime of prior infections.

The delivery method may also need to change. While tested as a nasal spray in mice, it might require a nebulizer to reach deep into human lungs.

Researchers also must ensure that keeping the immune system on "amber alert" does not cause harmful side effects. "We have to ensure that keeping the body on high alert doesn't lead to friendly fire," cautioned Prof Jonathan Ball of the Liverpool School of Tropical Medicine.

Potential future uses

The Stanford team does not envision this replacing all current vaccines. Instead, they see it as a complementary tool for specific situations.

One scenario is the early phase of a pandemic. A universal vaccine could buy critical time and save lives while a pathogen-specific vaccine is developed. "That would reduce mortality, disease severity, and perhaps build up a level of immune resilience that would have a huge impact," said Pulendran.

Another is seasonal use. A spray at the start of winter could provide broad protection against the usual mix of circulating respiratory bugs. The researchers are now planning human challenge trials, where vaccinated volunteers are deliberately exposed to a pathogen to test the vaccine's efficacy.