Scientists at Stanford Medicine have developed a new type of “universal” nasal spray vaccine that could one day protect against a wide range of respiratory illnesses, including COVID-19, influenza, bacterial pneumonia, and even common allergens.

Unlike traditional vaccines that target a specific virus or bacterium, the experimental spray works by boosting the lungs’ natural immune defenses, keeping them on high alert for months against many different threats. The findings were published in the journal Science.

In animal studies, the vaccine significantly reduced viral levels, prevented severe disease, and even blocked allergic reactions.

Mice received the vaccine as droplets in their noses, with some given multiple doses a week apart. Afterward, they were exposed to respiratory viruses.

Mice that received three doses remained protected from SARS-CoV-2 and other coronaviruses for at least three months. Unvaccinated mice, however, suffered severe weight loss, developed heavy lung inflammation, and often died. By contrast, vaccinated mice lost little weight, all survived, and their lungs showed very low viral levels.

Researchers also tested the vaccine against bacterial pathogens such as Staphylococcus aureus and Acinetobacter baumannii, both common causes of hospital-acquired infections. Vaccinated mice were protected from these bacteria for about three months.

For decades, scientists have pursued the idea of a universal vaccine capable of guarding against many infectious diseases, but the goal has often seemed unrealistic.

Most broad-spectrum vaccine efforts focus on one viral family, such as all coronaviruses or all flu strains. A single vaccine that protects against unrelated pathogens has generally been considered unlikely.

The new study, published February 19 in Science, showed protection not only against multiple viruses and bacteria but also against house dust mites, a common allergen.

Senior author Bali Pulendran, PhD, said the breadth of protection exceeded expectations. If similar results are seen in humans, a single nasal spray could potentially replace multiple yearly shots for seasonal respiratory illnesses and offer rapid protection against future pandemic viruses.

Human testing is the next step, beginning with a Phase I safety trial. If successful, larger studies will follow. Researchers estimate that two nasal doses may be sufficient for people. (Nigerian Tribune)