Health

For decades, researchers have pursued the development of a universal vaccine capable of providing protection against multiple infectious threats. This quest has often seemed almost mythical, but a significant advancement has emerged from Stanford Medicine. In a recent study involving mice, scientists have created an experimental universal vaccine that offers protection against a wide array of respiratory viruses, bacteria, and allergens. Administered intranasally, this vaccine appears to provide extensive lung protection that lasts for several months.

The findings, published on February 19 in the journal Science, indicate that vaccinated mice were safeguarded against SARS-CoV-2 and other coronaviruses, as well as common hospital-acquired infections such as Staphylococcus aureus and Acinetobacter baumannii. The vaccine demonstrated effectiveness against house dust mites, a prevalent allergen. According to Dr. Bali Pulendran, senior author of the study and a professor of microbiology and immunology, the level of protection observed exceeded initial expectations.

This innovative vaccine, referred to by researchers as GLA-3M-052-LS+OVA, may have the potential to replace the need for multiple annual vaccinations against seasonal respiratory illnesses and provide immediate protection against emerging pandemic viruses.

Understanding the Need for Current Vaccine Innovations

Traditional vaccines have relied on a principle known as antigen specificity since the late 1700s, when Edward Jenner introduced vaccination using cowpox to combat smallpox. Standard vaccines present a recognizable piece of a pathogen to the immune system, enabling the body to identify and respond to the actual virus effectively. However, as Dr. Pulendran points out, many pathogens, including viruses, can mutate rapidly, rendering previous vaccines less effective. What we have is why updated COVID-19 boosters and annual flu shots have become necessary.

Dr. Pulendran observed that “It’s becoming increasingly clear that many pathogens are able to quickly mutate. Like the proverbial leopard that changes its spots, a virus can change the antigens on its surface.” Most efforts to create broader vaccines have aimed to protect against entire viral families, targeting components that mutate less frequently, yet the notion of a single vaccine defending against multiple unrelated pathogens has been largely considered implausible.

A New Approach to Vaccine Development

This groundbreaking vaccine differentiates itself by mimicking the communication signals exchanged between immune cells during an infection. By linking the two primary defense systems of the body—innate and adaptive immunity—this innovative approach fosters a more coordinated and enduring immune response. Existing vaccines typically stimulate the adaptive immune system, which generates antibodies and specialized T cells targeting specific pathogens, while the innate immune system responds more broadly but usually for a shorter duration.

Dr. Pulendran emphasized the versatility of the innate immune system, noting that it can protect against a variety of microbes. Although innate immunity is generally short-lived, prior research has indicated that it can occasionally persist longer. For instance, the Bacillus Calmette-Guérin (BCG) tuberculosis vaccine, administered to roughly 100 million newborns annually, has been associated with reduced infant mortality from other infections, suggesting extended cross-protection.

In a study published in 2023, Dr. Pulendran’s team elucidated how the BCG vaccine triggers both innate and adaptive responses, maintaining innate activity for months. T cells recruited to the lungs as part of the adaptive response provided signals that sustained the activation of innate immune cells.

Mechanism of the Nasal Vaccine

The newly formulated nasal vaccine, GLA-3M-052-LS+OVA, is designed to replicate the T cell signals necessary for stimulating innate immune cells in the lungs. It includes a harmless protein, ovalbumin (OVA), which aids in drawing T cells into the lungs and prolonging the enhanced innate response.

In the study, mice received the vaccine as droplets administered through their noses, with some subjects receiving multiple doses spaced one week apart. Post-vaccination, mice were exposed to respiratory viruses, and those receiving three doses exhibited protection from SARS-CoV-2 and other coronaviruses for at least three months. In stark contrast, unvaccinated mice suffered severe weight loss and often succumbed to illness, displaying significant lung inflammation and high viral levels.

Dr. Pulendran described the immune response as a “double whammy,” wherein the sustained innate response reduced viral levels in the lungs by a factor of 700. If any viruses managed to bypass this primary defense, the adaptive immune response was primed to respond rapidly.

Broad Spectrum Protection Against Pathogens

In addition to its efficacy against viral infections, the vaccine was also tested against bacterial pathogens, including Staphylococcus aureus and Acinetobacter baumannii, providing protection for around three months. Researchers also explored the vaccine’s potential to guard against common allergens, exposing mice to proteins from house dust mites. While unvaccinated mice exhibited strong allergic reactions and mucus accumulation, those vaccinated demonstrated significantly milder responses, maintaining clear airways.

Dr. Pulendran asserted, “I consider what we have is a universal vaccine against diverse respiratory threats.”

Future Steps and Implications

The next phase of research will involve human testing, starting with a Phase I safety trial. If successful, further studies will follow, potentially incorporating controlled exposure to infections. Dr. Pulendran estimates that two doses delivered as a nasal spray may suffice for human application. With adequate funding, this universal respiratory vaccine could be available within the next five to seven years, enhancing defenses against future pandemics and simplifying seasonal vaccinations.

Dr. Pulendran envisions a future where individuals could receive a nasal spray in the fall that protects against various respiratory viruses, including COVID-19, influenza, and common allergens, revolutionizing medical practice.

This research was conducted in collaboration with scientists from Emory University School of Medicine, the University of North Carolina at Chapel Hill, Utah State University, and the University of Arizona. Funding was provided by the National Institutes of Health and various endowments.

As this promising research progresses, the medical community eagerly anticipates the potential for a transformative approach to respiratory illness prevention. Readers are encouraged to share their thoughts and engage in discussions about these exciting developments.