Nasal Vaccine Booster Outperforms mRNA Shots: NUS & Monash Study

A new study suggests a potential upgrade to vaccine boosters: an intranasal spray that may trigger a more robust and broadly protective immune response against sarbecoviruses – the family of viruses that includes SARS-CoV-2, the virus responsible for COVID-19 and its variants. Researchers at the Yong Loo Lin School of Medicine, National University of Singapore (NUS Medicine), working with colleagues at Monash University in Australia, found that this nasal vaccine booster outperformed conventional mRNA boosters in preclinical testing, particularly in generating immune responses directly within the lungs and nasal tissues.

How Intranasal Boosters Differ

Traditional mRNA vaccines, delivered via injection, stimulate the immune system to produce antibodies that circulate in the bloodstream. While effective, these antibodies may not always be present in high concentrations at the initial site of infection – the nasal passages, and lungs. An intranasal vaccine, delivered directly into the nose, aims to establish a stronger immune presence at these critical entry points. This approach, researchers believe, could lead to more effective protection against infection and potentially reduce the severity of illness. The study, published in The Journal of Clinical Investigation, examined alternative booster candidates and delivery methods to improve immunity to sarbecoviruses.

The research team, led by Associate Professor Sylvie Alonso and Dr. Nicholas Cheang from NUS Medicine’s Department of Microbiology and Immunology and Infectious Diseases Translational Research Programme, demonstrated that the intranasal booster elicited strong neutralizing antibody responses and a significant increase in resident T cells within the lung and nasal tissues. T cells are crucial components of the immune system, playing a key role in clearing infected cells and providing long-lasting immunity. Read more about the study findings here.

Sarbecoviruses: A Broader Threat

The focus on sarbecoviruses is significant because this viral family poses an ongoing threat to global health. Beyond SARS-CoV-2, sarbecoviruses include SARS-CoV-1, which caused the 2003 SARS outbreak, and a range of other bat coronaviruses with the potential to spill over into human populations. Developing broadly protective vaccines and boosters against this entire family of viruses is a key priority for researchers. The NUS Medicine and Monash University study specifically investigated ways to improve protective immunity and longevity against these viruses.

What the Study Involved

The study involved examining different vaccine booster candidates and how they were administered. Researchers compared the intranasal booster to conventional mRNA boosters, assessing the immune responses generated in both the bloodstream and the respiratory tissues. The findings suggest that the intranasal approach is particularly effective at stimulating immune responses where they are most needed – directly at the site of potential infection. The research team included Assoc Prof Mireille Lahoud from Monash Biomedicine Discovery Institute and Dr Kirsteen Tullett, also from Monash Biomedicine Discovery Institute.

Limitations and Next Steps

It’s critical to note that this research is currently in its early stages. The study was conducted in a preclinical setting, meaning the results have not yet been replicated in human trials. While the findings are promising, further research is needed to confirm the efficacy and safety of intranasal boosters in humans. The study’s authors acknowledge that additional investigation is required to fully understand the long-term effects of this approach and to determine the optimal dosage and administration schedule.

The next steps involve conducting clinical trials to evaluate the intranasal booster in human volunteers. These trials will assess the safety, immunogenicity (the ability to trigger an immune response), and efficacy of the booster in preventing infection and reducing disease severity. Researchers will also be investigating the potential for this approach to provide broader protection against different sarbecovirus variants.

NUS Medicine: A Regional Hub for Research

The Yong Loo Lin School of Medicine at the National University of Singapore (NUS Medicine) has a long history of medical education and research. Established in 1905 as the Straits Settlements and Federated Malay States Government Medical School, it has evolved into a leading medical school in Singapore and the region. Learn more about the school’s history and programs here. NUS Medicine is actively involved in research on infectious diseases, cancer, and other major health challenges, and plays a key role in training the next generation of healthcare professionals.

What This Means for Future Vaccine Strategies

The development of an effective intranasal vaccine booster could have significant implications for future pandemic preparedness and response. By stimulating a stronger and more localized immune response, this approach may offer enhanced protection against respiratory viruses and reduce the necessitate for frequent booster shots. But, it’s crucial to remember that vaccines are just one component of a comprehensive public health strategy. Other measures, such as mask-wearing, social distancing, and improved ventilation, remain important tools for preventing the spread of infectious diseases.

The ongoing research at NUS Medicine and Monash University, along with similar efforts around the world, underscores the importance of continued investment in vaccine research and development. As new variants emerge and the threat of future pandemics looms, innovative approaches to vaccine delivery and formulation will be essential for protecting global health.

Looking Ahead: Clinical Trial Timelines

While specific timelines for clinical trials are not yet available, researchers are actively working to secure funding and regulatory approvals to initiate human studies as soon as possible. The process of bringing a new vaccine booster to market typically involves several phases of clinical trials, each designed to assess different aspects of safety and efficacy. Public health authorities will carefully review the data from these trials before making any recommendations regarding the use of the intranasal booster.