A New Formula for Stronger, Longer-Lasting Vaccines

Why Do Vaccines Need to Become More Effective?

Today's vaccines are highly successful at protecting against many diseases. Improving them remains essential, however, to make that protection stronger and longer-lasting. Increasing the effectiveness of vaccines against diseases such as COVID-19 and HIV is particularly important for protecting public health and creating immunity resilient to emerging variants. Stanford University researchers have developed a new system combining two types of adjuvant to substantially improve vaccine effectiveness.

Adjuvants are substances that enhance the body's response to a vaccine by stimulating the immune system more strongly. They are often used to improve vaccine effectiveness and provide longer-lasting protection.

A New Vaccine Helper From Stanford University

Stanford University researchers developed a customizable approach to improving vaccine effectiveness: a new adjuvant system. In laboratory tests, this experimental additive substantially improved the performance of COVID-19 and HIV vaccine candidates. The researchers also noted that it could be adapted to stimulate immune responses against different pathogens and tailored for vulnerable groups such as children and older adults.

Lead author Ben Ou emphasized that existing vaccines are not perfect and many do not provide lasting immunity. According to Ou, designing stronger adjuvants is one way to improve vaccines.

The Power of Saponins and TLR Agonists

Researchers developed spherical structures made from immune-stimulating molecules called saponins: nanoparticles. TLR agonists, which have considerable potential to stimulate different immune responses, were added to these nanoparticles.

Toll-like receptors (TLRs): Toll-like receptors are important cell-surface proteins that recognize microorganisms and initiate immune responses. By interacting with specific molecular structures of pathogens, TLRs activate the innate immune response.

TLR agonists: TLR agonists are molecules that activate the immune system by stimulating TLRs. They are used in vaccine development to strengthen immune responses.

In tests involving COVID-19 and HIV vaccines, the new adjuvant platform produced stronger and longer-lasting effects than commonly used aluminum-based adjuvants. In particular, the vaccine combination developed against SARS-CoV-2 was also found effective against various variants, including Delta and Omicron.

The History of Adjuvants: A 100-Year Journey

Adjuvants are components that strengthen vaccines' immune responses. The first were aluminum salts used in pertussis, diphtheria and tetanus vaccines in the 1920s. Today, a wide range of new-generation adjuvants is used, from saponin-based compounds to synthetic DNA adjuvants. TLR agonists have attracted particular interest in vaccine science in recent years. By stimulating the immune system, they produce higher antibody levels and longer-lasting protection.

Tailoring Vaccines: The Vaccine Technology of the Future

The customizable nature of TLR agonists will allow vaccines to be adapted for different age groups and health conditions. The human immune system changes dramatically throughout life, so vaccines need to reflect these changes for maximum effectiveness and safety. Stanford researchers hope their nanoparticle platform can be used to test different TLR agonist-adjuvant combinations and contribute to developing more effective vaccines in the future.

Conclusion

This study represents an important advance in using adjuvants more effectively to improve vaccine performance and generate broader immune responses. Although human studies will take time, the innovative platform could open the way to vaccines that provide more effective and longer-lasting immunity.