In recent years, significant advances in flu vaccines have been made in response to the virus’s rapid evolution and the urgent need for broader and longer-lasting protection. Traditional flu vaccines, which typically target specific influenza strains predicted before the flu season, have proven effective in reducing severe cases, hospitalizations, and deaths. However, as the influenza virus constantly mutates, scientists are developing innovative methods to improve vaccine effectiveness, including universal flu vaccines, mRNA-based vaccines, and more sophisticated delivery methods.
One of the primary goals in flu vaccine research is creating a universal flu vaccine that can provide broader and longer-lasting immunity against various strains of the influenza virus. By targeting stable areas of the virus, researchers aim to develop vaccines that can offer protection across multiple influenza strains, potentially lasting for several years instead of requiring annual updates. A successful universal flu vaccine could revolutionize public health by reducing the annual flu vaccine production cycle, increasing vaccine efficacy, and improving the global response to seasonal and pandemic influenza 1,2. Research in this area is still ongoing.
Another area of research for flu vaccines that has seen some advances recently focuses on mRNA technology, which would allow rapid updates to vaccines based on current flu strains, and has seen some advances recently. Although more complex than nasal sprays, mRNA flu vaccines—like those developed for COVID-19—could improve efficacy in future seasons, as they allow for fine-tuning to counter seasonal flu mutations more precisely 3. However, this technology is not yet ready for use in flu vaccines.
Advances in vaccine delivery and formulation are also enhancing the efficacy of flu vaccines. New adjuvants—substances added to vaccines to improve the immune response—are being developed to make flu vaccines more effective, especially in populations with weaker immune systems, such as the elderly. Intranasal flu vaccines, which mimic the natural route of infection through the respiratory tract, represent another area of interest 4,5.
A recent milestone in flu vaccines was the Food and Drug Administration (FDA)’s recent approval of FluMist as the first self-administered flu vaccine, the culmination of many years of hard work and research advances. Manufactured by AstraZeneca, FluMist is a nasal spray vaccine that uses a weakened version of the virus and has been available through healthcare providers since 2003 6,7. Now, with FDA approval for at-home use, adults can administer it themselves or provide it to their children, pending a prescription. The convenience of self-administration is intended to expand accessibility and encourage more widespread flu protection. This reflects a growing trend in healthcare toward patient autonomy and telemedicine, where healthcare can be delivered and managed remotely. For many, the ease of at-home administration could reduce barriers to vaccination, especially for those with limited access to healthcare facilities.
Overall, flu vaccine advancements like self-administered options are transforming public health approaches to influenza. By combining traditional vaccine knowledge with modern technology, these new solutions aim to make flu prevention more accessible and effective for a broad spectrum of people. As these advances in flu vaccines reach the public, they hold promise for higher vaccination rates and a more resilient approach to seasonal influenza.
References
1. Krammer, F., García-Sastre, A. & Palese, P. Is It Possible to Develop a “Universal” Influenza Virus Vaccine? Potential Target Antigens and Critical Aspects for a Universal Influenza Vaccine. Cold Spring Harbor Perspectives in Biology 10, a028845 (2018). doi: 10.1101/cshperspect.a028845
2. Researchers getting closer to a “universal” flu vaccine | PNAS. https://www.pnas.org/doi/10.1073/pnas.2123477119.
3. What are mRNA vaccines and how do they work?: MedlinePlus Genetics. https://medlineplus.gov/genetics/understanding/therapy/mrnavaccines/.
4. Mohan, T., Verma, P. & Rao, D. N. Novel adjuvants & delivery vehicles for vaccines development: A road ahead. The Indian Journal of Medical Research 138, 779 (2013).
5. Zhao, T. et al. Vaccine adjuvants: mechanisms and platforms. Sig Transduct Target Ther 8, 1–24 (2023).doi: 10.1038/s41392-023-01557-7
6. FluMist approved for self-administration in the US. https://www.astrazeneca.com/media-centre/press-releases/2024/flumist-approved-for-self-administration-in-the-us.html (2024).
7. Commissioner, O. of the. FDA Approves Nasal Spray Influenza Vaccine for Self- or Caregiver-Administration. FDA https://www.fda.gov/news-events/press-announcements/fda-approves-nasal-spray-influenza-vaccine-self-or-caregiver-administration (2024).
