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

A universal nasal spray vaccine shows promise

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 approach represents a fundamental shift from how vaccines have worked for over two centuries.

The team's findings, published in the journal Science, show the vaccine puts immune cells in the lungs on high alert. This state lasted about three months in animals and led to a 100-to-1,000-fold reduction in viruses penetrating the body.

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 takes a different path.

It mimics the way immune cells communicate. The nasal spray leaves lung-based white blood cells, called macrophages, in a primed state of readiness. "This vaccine elicits a far broader response," said lead researcher Prof Bali Pulendran.

He told the BBC it is protective against "virtually all viruses, and as many different bacteria as we've tested." The team demonstrated protection against influenza, COVID-19, common cold viruses, and the bacteria Staphylococcus aureus and Acinetobacter baumannii.

Potential benefits and expert reaction

Experts not involved in the research called it "really exciting" and a potential "major step forward." The vaccine's broad activation also seemed to reduce the immune response to house dust mite allergens, a common trigger for allergic asthma.

Prof Daniela Ferreira, a vaccinology professor at the University of Oxford, said it could "change how we protect people from common coughs, colds and other respiratory infections" if human trials succeed.

The envisioned uses for such a vaccine include:

• Buying critical time at the start of a pandemic before a pathogen-specific vaccine is ready.
• Acting as a seasonal spray at the start of winter to provide broad protection against circulating bugs.
• Complimenting, not replacing, existing vaccines that provide long-term, specific immunity.

Major questions and next steps

The research is at an early stage, and significant hurdles remain before it could be used in people. The vaccine was tested in animals and must now proceed to human clinical trials.

Key unanswered questions include whether the same potent effect can be achieved in humans and how long the "amber alert" state would last. Our immune systems are more complex and shaped by a lifetime of previous infections compared to lab animals.

There are also safety concerns. "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. Permanently dialing up the immune system could risk unintended side effects or autoimmune reactions.

The researchers plan initial human trials where a vaccinated person is deliberately challenged with an infection to see how their body responds. They also note the nasal spray used in mice may need to be delivered via a nebulizer to reach deep into human lungs effectively.