A single nasal spray vaccine could offer broad protection against a range of respiratory illnesses, including the common cold, flu, COVID-19, and even bacterial lung infections, according to new research from Stanford University. The vaccine, which is still in the early stages of development, has demonstrated promising results in animal studies and could potentially reduce the need for multiple annual vaccinations.
The research, published in the journal Science on , represents a significant departure from traditional vaccine design. For over two centuries, vaccines have relied on antigen specificity – training the immune system to recognize and fight off a specific pathogen, like the spike proteins of SARS-CoV-2. This new approach, however, focuses on enhancing the innate immune response, essentially putting the body’s defenses on “amber alert” rather than targeting a specific invader.
“I think what we have is a universal vaccine against diverse respiratory threats,” said Dr. Bali Pulendran, PhD, professor of microbiology and immunology at Stanford Medicine and senior author of the study. The vaccine works by mimicking the way immune cells communicate with each other, prompting white blood cells in the lungs – macrophages – to become primed and ready to respond to any incoming infection. In animal trials, this heightened state of readiness led to a substantial reduction – between 100- to 1,000-fold – in the amount of virus able to penetrate the lungs.
The study demonstrated protection against a surprisingly wide spectrum of respiratory threats in mice, including SARS-CoV-2 and other coronaviruses, Staphylococcus aureus and Acinetobacter baumannii (common hospital-acquired infections), and even house dust mites, a common allergen. This suggests the vaccine could potentially alleviate symptoms of allergic rhinitis as well as viral and bacterial infections.
Experts in the field are cautiously optimistic. “This is really exciting,” said Professor Daniela Ferreira, a professor of vaccinology at the University of Oxford, who was not involved in the study. “If these results are confirmed in human studies, it could change the way we protect people from coughs, colds, and other respiratory infections.”
The current paradigm of vaccination, pioneered by Edward Jenner in the late 18th century, focuses on providing immunity to a single disease at a time. A measles vaccine protects against measles, and a chickenpox vaccine protects against chickenpox. This new approach, however, aims for broader, more comprehensive protection.
The vaccine is administered as a nasal spray, delivering the immune-boosting signal directly to the lungs. Researchers found the effect lasted for approximately three months in animal experiments. For viruses that did manage to bypass the initial defenses, the rest of the immune system was “poised, ready to fend off these in warp speed time,” according to Dr. Pulendran.
While the results are encouraging, several hurdles remain before this vaccine can become a reality for humans. The Stanford team is planning to initiate human clinical trials, beginning with safety trials followed by larger studies where participants would be intentionally exposed to infections to assess the vaccine’s effectiveness. Researchers estimate that two doses of the nasal spray may be sufficient to provide protection.
One key question is whether the same effect can be achieved in humans, given the differences between the immune systems of mice and humans. Human immunity is shaped by decades of exposure to various pathogens, a factor not fully replicated in animal models. The method of delivery may need to be adjusted. While a nasal spray was effective in mice, it’s possible that a nebulizer – a device that delivers medication in a fine mist – might be necessary to reach deeper into the lungs in humans.
There are also potential concerns about the long-term effects of keeping the immune system in a constant state of heightened alert. Some experts caution that this could lead to unintended consequences, such as autoimmune reactions. “We need to make sure that keeping the body in a state of ‘high alert’ doesn’t lead to ‘friendly fire’,” explained Professor Jonathan Ball, a professor of molecular virology at the University of Liverpool. However, the Stanford research team believes that the vaccine is intended to be used as a complement to existing vaccines, not a replacement.
Looking ahead, Dr. Pulendran envisions a scenario where a seasonal nasal spray could provide broad protection against winter respiratory viruses, including COVID-19, influenza, and the common cold. “Imagine getting a nasal spray in the fall months that protects you from all respiratory viruses including COVID-19, influenza, respiratory syncytial virus and the common cold, as well as bacterial pneumonia and early spring allergens,” he said. “That would transform medical practice.” The vaccine could also prove invaluable in the early stages of a pandemic, providing a crucial bridge while a more targeted vaccine is developed.
If all goes well, researchers estimate the vaccine could be available in five to seven years, contingent upon sufficient funding and successful clinical trials. The development of this “universal vaccine” represents a potentially transformative step forward in the fight against respiratory illnesses, offering a glimpse of a future where a single dose could provide comprehensive protection against a wide range of threats.
