Key TakeawaysCompared to the traditional shot-in-the-arm flu vaccines, intranasal vaccines activate a more robust and durable immune response.Research has shown that tackling a respiratory viral infection locally (in the nose and throat) with an intranasal vaccine can produce a strong mucosal immune response.Intranasal vaccines are also more cost-effective and can be mass-produced for a large population in an emergency, such as a pandemic.

Key Takeaways

Compared to the traditional shot-in-the-arm flu vaccines, intranasal vaccines activate a more robust and durable immune response.Research has shown that tackling a respiratory viral infection locally (in the nose and throat) with an intranasal vaccine can produce a strong mucosal immune response.Intranasal vaccines are also more cost-effective and can be mass-produced for a large population in an emergency, such as a pandemic.

The results also confirm that a mucosal antibody reaction could provide long-lasting immunity to upper respiratory viruses includinginfluenza, HIV, and SARS-CoV-2, the virus that causes COVID-19.

“Durability is one of the advantages of an intranasal adenovirus vaccine,” Mark Connors, MD, chief of the HIV-Specific Immunity Section at the National Institute of Allergy and Infectious Diseases Laboratory of Immunoregulation and co-author of the new research on the intranasal flu vaccine, tells Verywell. “It produces long-term mucosal immunity, and when tested in animal models, it shuts the virus down.”

What This Means For YouAn intranasal influenza vaccine has shown promise in clinical trials. One day, it might replace our current shot-in-the-arm flu vaccine. The technology may also become a tool that we can use against other respiratory viruses and a strategy to help us prevent future pandemics like COVID-19.

What This Means For You

An intranasal influenza vaccine has shown promise in clinical trials. One day, it might replace our current shot-in-the-arm flu vaccine. The technology may also become a tool that we can use against other respiratory viruses and a strategy to help us prevent future pandemics like COVID-19.

Intranasal Vaccines Versus Traditional Flu Shots

Historically,vaccination has been an important toolfor reducing the incidence of influenza illness and hospitalizations related to the infection. However,flu shot effectiveness varies.

A 2011 study found that the current flu vaccines—which include both inactive andlive-attenuated (weakened) vaccines—are only 59% effective in adults ages 18 to 65.

These findings highlight why new vaccines need to be created to improve clinical efficacy and effectiveness. Vaccines need to be able to keep up with the widely mutated influenza strains that we are presented with each year.

Understanding Flu Vaccine Effectiveness

Are Intranasal Vaccines More Effective?

The intranasal influenza vaccine uses a weakened adenovirus—for example, thecommon cold—as a vector to introduce the foreign antigens needed to produce a robust immune response.The traditional flu vaccine uses a killed or weakened version of the influenza virus to produce an immune response.

Since influenza is a contagious respiratory virus that infects the nose, throat, and sometimes the lungs, introducing a vaccine at the local level (intranasally) can produce a highly effective and stronger mucosal immune response. This, in turn, results in longer immunity and is critical for preventing the transmission of respiratory viruses that infect the mucosal tissue.

“Producing mucosal immunity locally is the first advantage of the intranasal influenza vaccine,” Connors says. “This route could also be promising in other respiratory infections includingHIVand SARS-CoV-2.”

Experts: Get a COVID-19 Vaccine Even If You Don’t Typically Get a Flu Shot

Why We Need New Vaccines

With the COVID-19 pandemic and the need tomass vaccinatea large population, intranasal vaccines may emerge as a cost-effective measure to not only improve existing influenza vaccine technology but as a strategy to prepare us for future pandemics.

The authors of a 2016 study on the current prospects and future challenges of nasal vaccine delivery noted that with the “increased need to immunize large populations, potentially in swift response to pandemics, there is a clear need to have strategies in place.”

The study also highlighted that while there is agreat deal of research underwayto advance the design of intranasal vaccines, these studies face several challenges—such as the high cost of clinical trials and the correlating immune responses in animal models with humans.

How to Safely Get a Flu Shot During the COVID-19 Pandemic

The COVID-19 pandemic also accelerated the use of abreakthrough vaccine technique. In just 10 months, researchers were able to create safe and effective vaccines using synthetic mRNA—a technology that could change vaccines forever.

7 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Matsuda K, Migueles S, Huang J, Bolkhovitinov L, Stuccio S, Griesman T.A replication competent adenovirus-vectored influenza vaccine induces durable systemic and mucosal immunity.J Clin Invest.2021;131(5):e140794. doi:10.1172/JCI140794Centers for Disease Control and Prevention (CDC).Cell-based flu vaccines.Osterholm M, Kelley N, Sommer A, Belongia E.Efficacy and effectiveness of influenza vaccines: a systematic review and meta-analysis.Lancet Infect Dis. doi:10.1016/S1473-3099(11)70295-XWold WS, Toth K.Adenovirus vectors for gene therapy, vaccination and cancer gene therapy.Curr Gene Ther. 2013;13(6):421-433. doi:10.2174/1566523213666131125095046Centers for Disease Control and Prevention (CDC).How influenza (flu) vaccines are made.Centers for Disease and Control and Prevention (CDC).Key facts about influenza (flu).Yusuf H, Kett V.Current prospects and future challenges for nasal vaccine delivery.Hum Vaccin Immunother. 2017;13(1):34-45. doi:10.1080/21645515.2016.1239668

7 Sources

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Matsuda K, Migueles S, Huang J, Bolkhovitinov L, Stuccio S, Griesman T.A replication competent adenovirus-vectored influenza vaccine induces durable systemic and mucosal immunity.J Clin Invest.2021;131(5):e140794. doi:10.1172/JCI140794Centers for Disease Control and Prevention (CDC).Cell-based flu vaccines.Osterholm M, Kelley N, Sommer A, Belongia E.Efficacy and effectiveness of influenza vaccines: a systematic review and meta-analysis.Lancet Infect Dis. doi:10.1016/S1473-3099(11)70295-XWold WS, Toth K.Adenovirus vectors for gene therapy, vaccination and cancer gene therapy.Curr Gene Ther. 2013;13(6):421-433. doi:10.2174/1566523213666131125095046Centers for Disease Control and Prevention (CDC).How influenza (flu) vaccines are made.Centers for Disease and Control and Prevention (CDC).Key facts about influenza (flu).Yusuf H, Kett V.Current prospects and future challenges for nasal vaccine delivery.Hum Vaccin Immunother. 2017;13(1):34-45. doi:10.1080/21645515.2016.1239668

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

Matsuda K, Migueles S, Huang J, Bolkhovitinov L, Stuccio S, Griesman T.A replication competent adenovirus-vectored influenza vaccine induces durable systemic and mucosal immunity.J Clin Invest.2021;131(5):e140794. doi:10.1172/JCI140794Centers for Disease Control and Prevention (CDC).Cell-based flu vaccines.Osterholm M, Kelley N, Sommer A, Belongia E.Efficacy and effectiveness of influenza vaccines: a systematic review and meta-analysis.Lancet Infect Dis. doi:10.1016/S1473-3099(11)70295-XWold WS, Toth K.Adenovirus vectors for gene therapy, vaccination and cancer gene therapy.Curr Gene Ther. 2013;13(6):421-433. doi:10.2174/1566523213666131125095046Centers for Disease Control and Prevention (CDC).How influenza (flu) vaccines are made.Centers for Disease and Control and Prevention (CDC).Key facts about influenza (flu).Yusuf H, Kett V.Current prospects and future challenges for nasal vaccine delivery.Hum Vaccin Immunother. 2017;13(1):34-45. doi:10.1080/21645515.2016.1239668

Matsuda K, Migueles S, Huang J, Bolkhovitinov L, Stuccio S, Griesman T.A replication competent adenovirus-vectored influenza vaccine induces durable systemic and mucosal immunity.J Clin Invest.2021;131(5):e140794. doi:10.1172/JCI140794

Centers for Disease Control and Prevention (CDC).Cell-based flu vaccines.

Osterholm M, Kelley N, Sommer A, Belongia E.Efficacy and effectiveness of influenza vaccines: a systematic review and meta-analysis.Lancet Infect Dis. doi:10.1016/S1473-3099(11)70295-X

Wold WS, Toth K.Adenovirus vectors for gene therapy, vaccination and cancer gene therapy.Curr Gene Ther. 2013;13(6):421-433. doi:10.2174/1566523213666131125095046

Centers for Disease Control and Prevention (CDC).How influenza (flu) vaccines are made.

Centers for Disease and Control and Prevention (CDC).Key facts about influenza (flu).

Yusuf H, Kett V.Current prospects and future challenges for nasal vaccine delivery.Hum Vaccin Immunother. 2017;13(1):34-45. doi:10.1080/21645515.2016.1239668

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