Universal Nasal Spray Vaccine Could Protect Against Multiple Respiratory Illnesses
A single nasal spray vaccine may offer protection against all coughs, colds, flus, bacterial lung infections, and potentially alleviate allergies, according to researchers from Stanford University in the US.
The team has conducted tests of their "universal vaccine" in animal models, with human clinical trials yet to be initiated.
This approach represents a "radical departure" from vaccine design methods used for over two centuries, the researchers state.
Innovative Vaccine Approach Differs from Traditional Immunisation
Experts in the field have described the study as "really exciting" despite its early stage and consider it a "major step forward" in vaccine development.
Conventional vaccines train the immune system to combat a specific infection. For example, the measles vaccine targets only measles, and the chickenpox vaccine protects solely against chickenpox. This has been the basis of immunisation since Sir Edward Jenner pioneered vaccines in the late 18th century.
The method detailed in the journal Science does not train the immune system in the traditional sense. Instead, it mimics the communication between immune cells.
Administered as a nasal spray, the vaccine primes white blood cells in the lungs, known as macrophages, placing them on "amber alert" to respond rapidly to any invading infection.
In animal experiments, this heightened immune readiness persisted for approximately three months.
The researchers observed that this state of alertness resulted in a 100-to-1,000-fold reduction in viruses penetrating the lungs and entering the body.
For viruses that did manage to bypass this initial defense, the remainder of the immune system was "poised, ready to fend off these in warp speed time," explained Professor Bali Pulendran, a professor of microbiology and immunology at Stanford.
Broad Protection Against Viruses, Bacteria, and Allergens
The vaccine also demonstrated protection against two bacterial species: Staphylococcus aureus and Acinetobacter baumannii.
Professor Pulendran told the BBC:
"This vaccine, what we term a universal 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, and even allergens.
"The principle by which this vaccine works is a radical departure from the principle by which all vaccines have worked so far."
Additionally, the vaccine's modulation of the immune system appeared to reduce responses to house dust mite allergens, which are known triggers of allergic asthma.
Expert Perspectives on the Research
Professor Daniela Ferreira, a professor of vaccinology at the University of Oxford who was not involved in the study, described the research as:
"A really exciting piece of research."
She noted that if the findings are confirmed in human studies, the vaccine could "change how we protect people from common coughs, colds and other respiratory infections." She also highlighted:
"One of the strengths" of the study was a clear explanation of how this new style of vaccine was working.
Ferreira added that the research "could mark a major step forward" by offering protection against infections that "place such a heavy burden" on populations worldwide.
Outstanding Questions and Future Trials
Despite promising results, many questions remain unanswered.
While the vaccine was administered as a nasal spray in animal experiments, it may require delivery via a nebuliser to reach the deeper regions of human lungs.
It is currently unknown whether the same immune response can be elicited in humans or how long the immune system would remain in the heightened "amber alert" state. Differences exist between mouse and human immune systems, including the influence of decades of prior infections on human immunity.
The researchers plan to conduct trials involving deliberate infection of vaccinated individuals to assess how their bodies respond.
Potential risks of maintaining the immune system in a heightened state include the possibility of immune disorders.
Jonathan Ball, professor of molecular virology at the Liverpool School of Tropical Medicine, commented on the study:
"The work was undeniably exciting but cautioned 'we have to ensure that keeping the body on 'high alert' doesn't lead to friendly fire, where a hyper-ready immune system accidentally triggers unwelcome side effects'."
Potential Applications and Complementary Use
The US research team does not advocate for permanently elevating the immune system and suggests that such a vaccine would complement rather than replace existing vaccines.
In the early stages of a pandemic, such as the onset of Covid-19 in 2020, a universal vaccine could provide critical time and save lives while a targeted vaccine is developed.
Professor Pulendran stated:
"That would reduce mortality, disease severity, and perhaps build up a level of immune resilience that would have a huge impact."
Another potential use is at the start of winter, when various respiratory viruses circulate widely. A seasonal nasal spray could be administered to establish broad immunity against multiple pathogens.
