VACCINE EFFECTIVENESS

Consistent effectiveness across multiple seasons with FluMist1-6

Comparable vaccine effectiveness of FluMist (LAIV) and IIV1-6

Vaccine Effectiveness Chart Vaccine Effectiveness Chart

Results are descriptive only. This information may not be all-inclusive as it is intended to be a concise summary of representative data on vaccine effectiveness.

*2% of doses were FluMist.

†8% of doses were FluMist.

CI=confidence interval; Dept.=department; IIV=inactivated influenza vaccine; LAIV=live attenuated influenza vaccine; UK=United Kingdom; VE=vaccine effectiveness.

Important Safety Information

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Important Safety Information

  • Do not administer FLUMIST to persons who have had a severe allergic reaction (e.g., anaphylaxis) to any component of the vaccine, including egg protein, or after a previous dose of any influenza vaccine, or to children and adolescents through 17 years of age who are receiving aspirin or aspirin-containing therapy
  • When administered in a healthcare setting, appropriate medical treatment must be immediately available to manage potential anaphylactic reactions. When self-administered or administered by a caregiver, immediate medical attention should be sought if the vaccine recipient experiences symptoms of an allergic reaction
  • In clinical trials, the risks of hospitalization and wheezing were increased in children younger than 2 years of age who received FLUMIST
  • Children younger than 5 years of age with recurrent wheezing and persons of any age with asthma may be at increased risk of wheezing following the administration of FLUMIST. FLUMIST has not been studied in persons with severe asthma or active wheezing
  • If Guillain-Barré syndrome has occurred within 6 weeks of any prior influenza vaccination, the decision to give FLUMIST should be based on careful consideration of potential benefits and risks
  • The effectiveness of FLUMIST has not been studied in immunocompromised persons
  • The safety of FLUMIST in individuals with underlying medical conditions that may predispose them to complications following wild-type influenza infection has not been established
  • FLUMIST may not protect all individuals receiving the vaccine
  • The most common solicited adverse reactions (≥10% in vaccine recipients and at least 5% greater than in placebo) reported after FLUMIST were runny nose or nasal congestion (ages 2-49 years), fever >100 °F (children
    ages 2-6 years), and sore throat (adult ages 18-49 years)

FLUMIST is a vaccine indicated for active immunization of persons 2 through 49 years of age for the prevention of influenza disease caused by influenza virus subtypes A and type B contained in the vaccine. FLUMIST is for intranasal administration only.

Please see full Prescribing Information, including Patient Information and Instructions for Use.

You may report side effects related to AstraZeneca products .

Reference:
  1. Data on File, REF-263898, AstraZeneca Pharmaceuticals LP.
References:
  1. Grohskopf LA, Blanton LH, Ferdinands JM, Reed C, Dugan VG, Daskalakis DC. Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices — United States, 2025–26 Influenza Season. MMWR Morb Mortal Wkly Rep. 2025;74(32):500-507. doi:10.15585/mmwr.mm7432a2
  2. Committee on Infectious Diseases. Recommendations for prevention and control of influenza in children, 2025–2026: policy statement. Pediatrics. 2025;156(6):e2025073620. doi:10.1542/ peds.2025-073620
  3. Vaccine pricing. Centers for Medicare & Medicaid Services (CMS). Accessed June 17, 2026. https://www.cms.gov/medicare/payment/part-b-drugs/vaccine-pricing
References:
  1. FLUMIST Prescribing Information.
  2. Grohskopf LA, Blanton LH, Ferdinands JM, Reed C, Dugan VG, Daskalakis DC. Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices — United States, 2025–26 Influenza Season. MMWR Morb Mortal Wkly Rep. 2025;74(32):500-507. doi:10.15585/mmwr.mm7432a2
  3. Grohskopf LA, Ferdinands JM, Blanton LH, Broder KR, Loehr J. Prevention and control of seasonal influenza with vaccines: recommendations of the advisory committee on immunization practices—United States, 2024–25 influenza season. MMWR Morb Mortal Wkly Rep. 2023;72(No. RR-2):1-25. doi:10.15585/mmwr.rr7305a1rr7202a1
  4. Grohskopf LA, Blanton LH, Ferdinands JM, Chung JR, Broder KR, Talbot HK. Prevention and control of seasonal influenza with vaccines: recommendations of the Advisory Committee on Immunization Practices–United States, 2023-24 influenza season. MMWR Morb Mortal Wkly Rep. 2023;72(No. RR-2):1-25. doi:10.15585/mmwr.rr7305a1rr7202a1
  5. Influenza vaccine products for the 2024-2025 influenza season. Accessed June 17, 2026. https://www.immunize.org/wp-content/uploads/catg.d/p4072.pdf
References:
  1. Giudice EL, Campbell JD. Needle-free vaccine delivery. Adv Drug Deliv Rev. 2006;58(1):68-89. doi:10.1016/j.addr.2005.12.003
  2. FLUMIST Prescribing Information.
  3. Vaccines and immunizations: Vaccine administration. Centers for Disease Control and Prevention. Accessed June 17, 2026. https://www.cdc.gov/vaccines/hcp/imz-best-practices/vaccine-administration.html?CDC_AAref_Val=https://www.cdc.gov/vaccines/hcp/acip-recs/general-recs/administration.html#cdc_report_pub_study_section_2-route-of-administration
  4. Murphy BR, Coelingh K. Principles underlying the development and use of live attenuated cold-adapted influenza A and B virus vaccines. Viral Immunol. 2002;15(2):295-323. doi:10.1089/08828240260066242
Reference:
  1. FLUMIST Prescribing Information.
References:
  1. Zhu S, Quint J, León TM, et al. Estimating influenza vaccine effectiveness against laboratory-confirmed influenza using linked public health information systems, California, 2023–2024 season. J Infect Dis. 2025;232(5):1249-1257.
  2. UK Health Security Agency. Surveillance of influenza and other seasonal respiratory viruses in the UK, winter 2023 to 2024; 2025. Accessed July 17, 2026. https://www.gov.uk/government/statistics/surveillance-of-influenza-and-other-seasonal-respiratory-viruses-in-the-uk-winter-2023-to-2024/surveillance-of-influenza-and-other-seasonal-respiratory-viruses-in-the-uk-winter-2023-to-2024#vaccination
  3. Zhu S, Quint J, León TM, et al. Influenza vaccine and associated infection and death in California, 2024 to 2025. JAMA Netw Open. 2026;9(6):e2617684.
  4. Rose AM, Lucaccioni H, Marsh K, et al; European IVE group. Interim 2024/25 influenza vaccine effectiveness: eight European studies, September 2024 to January 2025. Euro Surveill. 2025;30(7):2500102.
  5. Zhu S, Quint J, León TM, et al. Interim estimates of 2025–26 seasonal influenza vaccine effectiveness — California, October 2025–January 2026. MMWR Morb Mortal Wkly Rep. 2026;75(9):124-128.
  6. Lucaccioni H, Marques DFP, Kirsebom F, et al. Influenza vaccine effectiveness from nine studies during drifted A(H3N2) subclade K predominance, Europe, September 2025 to January 2026. Euro Surveill. 2026;31(7):2600109.
Reference:
  1. FLUMIST Prescribing Information.
Reference:
  1. Newall M, Morris C. Expanding flu vaccine. Ipsos. Accessed June 17, 2026. https://www.ipsos.com/en-us/news-polls/expanding-flu-vaccine
References:
  1. Grohskopf LA, Blanton LH, Ferdinands JM, Reed C, Dugan VG, Daskalakis DC. Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices — United States, 2025–26 Influenza Season. MMWR Morb Mortal Wkly Rep. 2025;74(32):500-507. doi:10.15585/mmwr.mm7432a2
  2. Committee on Infectious Diseases. Recommendations for prevention and control of influenza in children, 2025–2026: policy statement. Pediatrics. 2025;156(6):e2025073620. doi:10.1542/ peds.2025-073620
  3. Healthy People 2030. Increase the proportion of people who get the flu vaccine every year—IID-09. Office of Disease Prevention and Health Promotion, US Dept of Health and Human Services. Accessed June 17, 2026. https://health.gov/healthypeople/objectives-and-data/browse-objectives/vaccination/increase-proportion-people-who-get-flu-vaccine-every-year-iid-09
References:
  1. FLUMIST Prescribing Information.
  2. Update on influenza B/Yamagata surveillance. Centers for Disease Control and Prevention. Accessed June 17, 2026. https://stacks.cdc.gov/view/cdc/134669
  3. Summary minutes of 183rd Vaccines and Related Biological Products Advisory Committee. Virtual; October 5, 2023: FDA-2023-N-3300. US Food and Drug Administration. Accessed June 17, 2026. https://www.fda.gov/advisory-committees/advisory-committee-calendar/vaccines-and-related-biological-products-advisory-committee-october-5-2023-meeting-announcement?utm_medium=email&utm_source=govdelivery
  4. Types of influenza viruses. Centers for Disease Control and Prevention. Accessed June 17, 2026. https://www.cdc.gov/flu/about/viruses-types.html
  5. Appiah GD, Blanton L, D’Mello T, et al; Centers for Disease Control and Prevention (CDC). Influenza activity—United States, 2014–15 season and composition of the 2015–16 influenza vaccine. MMWR Morb Mortal Wkly Rep. 2015;64(21):583-590.
  6. Davlin SL, Blanton L, Kniss K, et al. Influenza activity—United States, 2015–16 season and composition of the 2016–17 influenza vaccine. MMWR Morb Mortal Wkly Rep. 2016;65(22):567-575. doi:10.15585/mmwr.mm6522a3
  7. Blanton L, Alabi N, Mustaquim D, et al. Update: influenza activity in the United States during the 2016–17 season and composition of the 2017–18 influenza vaccine. MMWR Morb Mortal Wkly Rep. 2017;66(25):668-676. doi:10.15585/mmwr.mm6625a3
  8. Garten R, Blanton L, Elal AIA, et al. Update: influenza activity in the United States during the 2017–18 season and composition of the 2018–19 influenza vaccine. MMWR Morb Mortal Wkly Rep. 2018;67(22):634-642. doi:10.15585/mmwr.mm6722a4
  9. Xu X, Blanton L, Elal AIA, et al. Update: influenza activity in the United States during the 2018–19 season and composition of the 2019–20 influenza vaccine. MMWR Morb Mortal Wkly Rep. 2019;68(24):544-551. doi:10.15585/mmwr.mm6824a3
  10. US virologic surveillance. Centers for Disease Control and Prevention. Accessed June 17, 2026. https://www.cdc.gov/flu/weekly/weeklyarchives2019-2020/Week14.htm
  11. Olsen SJ, Winn AK, Budd AP, et al. Changes in influenza and other respiratory virus activity during the COVID-19 pandemic—United States, 2020–2021. MMWR Morb Mortal Wkly Rep. 2021;70(29):1013-1019. doi:10.15585/mmwr.mm7029a1
  12. FluView summary ending on October 1, 2022. Centers for Disease Control and Prevention. Accessed June 17, 2026. https://www.cdc.gov/flu/weekly/weeklyarchives2021-2022/week39.htm
  13. Weekly U.S. influenza surveillance report key updates for week 23 ending June 10, 2023. Centers for Disease Control and Prevention. Accessed June 17, 2026. https://stacks.cdc.gov/view/cdc/129922
  14. FluView summary ending on October 1, 2022. Centers for Disease Control and Prevention. Accessed June 17, 2026. https://www.cdc.gov/flu/weekly/weeklyarchives2023-2024/week25.htm
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  16. Weekly US influenza surveillance report: key updates for week 21, ending May 30, 2026. Centers for Disease Control and Prevention. Accessed June 17, 2026. https://www.cdc.gov/fluview/surveillance/2026-week-21.html
References:
  1. FLUMIST Prescribing Information.
  2. Hayden FG, Palese P. Influenza virus. In: Richman DD, Whitley FJ, Hayden FG, eds. Clinical Virology. 4th ed. ASM Press; 2017:1009-1058.
  3. World Health Organization. The Immunological Basis for Immunization Series. Module 23: Influenza Vaccines. World Health Organization, Dept of Immunization, Vaccines and Biologicals; 2017:1-63.
  4. Murphy BR, Coelingh K. Principles underlying the development and use of live attenuated cold-adapted influenza A and B virus vaccines. Viral Immunol. 2002;15(2):295-323. doi:10.1089/08828240260066242
  5. Ambrose CS, Luke C, Coelingh K. Current status of live attenuated influenza vaccine in the United States for seasonal and pandemic influenza. Influenza Other Respir Viruses. 2008;2:193-202. doi:10.1111/j.1750-2659.2008.00056.x
  6. Wodi PA, Morelli V. Chapter 1: Principles of Vaccination. Centers for Disease Control and Prevention. Accessed June 17, 2026. https://www.cdc.gov/pinkbook/hcp/table-of-contents/chapter-1-principles-of-vaccination.html
  7. Vaccine administration. Centers for Disease Control and Prevention. Accessed June 17, 2026. https://www.cdc.gov/vaccines/hcp/imz-best-practices/vaccine-administration.html?CDC_AAref_Val=https://www.cdc.gov/vaccines/hcp/acip-recs/general-recs/administration.html
References:
  1. FLUMIST Prescribing Information.
  2. Wodi PA, Morelli V. Chapter 1: Principles of Vaccination. Centers for Disease Control and Prevention. Accessed June 17, 2026. https://www.cdc.gov/pinkbook/hcp/table-of-contents/chapter-1-principles-of-vaccination.html
  3. How flu spreads. Centers for Disease Control and Prevention. Accessed June 17, 2026. www.cdc.gov/flu/about/disease/spread.htm
  4. Different types of flu vaccines. Centers for Disease Control and Prevention. Accessed June 17, 2026. https://www.cdc.gov/flu/vaccine-types/?CDC_AAref_Val=https://www.cdc.gov/flu/prevent/different-flu-vaccines.htm
  5. Block SL, Yi T, Sheldon E, Dubovsky F, Falloon J. A randomized, double-blind noninferiority study of quadrivalent live attenuated influenza vaccine in adults. Vaccine. 2011;29(50):9391-9397. doi:10.1016/j.vaccine.2011.09.109
  6. Block SL, Falloon J, Hirschfield JA, et al. Immunogenicity and safety of a quadrivalent live attenuated influenza vaccine in children. Pediatr Infect Dis J. 2012;31(7):745-751. doi:10.1097/INF.0b013e31825687b0
  7. Hoft DF, Babusis E, Worku S, et al. Live and inactivated influenza vaccines induce similar humoral responses, but only live vaccines induce diverse T-cell responses in young children. J Infect Dis. 2011;204(6):845-853. doi:10.1093/infdis/jir436
  8. Ambrose CS, Wu X, Jones T, Mallory RM. The role of nasal IgA in children vaccinated with live attenuated influenza vaccine. Vaccine. 2012;30(48):6794-6801. doi:10.1016/j.vaccine.2012.09.018
  9. Barría MI, Garrido JL, Stein C, et al. Localized mucosal response to intranasal live attenuated influenza vaccine in adults. J Infect Dis. 2013;207(1):115-124. doi:10.1093/infdis/jis641
  10. Basha S, Hazenfeld S, Brady RC, Subbramanian RA. Comparison of antibody and T-cell responses elicited by licensed inactivated- and live-attenuated influenza vaccines against H3N2 hemagglutinin. Hum Immunol. 2011;72(6):463-469. doi:10.1016/j.humimm.2011.03.001
  11. Belshe RB, Gruber WC, Mendelman PM, et al. Correlates of immune protection induced by live, attenuated, cold-adapted, trivalent, intranasal influenza virus vaccine. J Infect Dis. 2000;181(3):1133-1137. doi:10.1086/315323
References:
  1. FLUMIST Prescribing Information.
  2. Grohskopf LA, Blanton LH, Ferdinands JM, Reed C, Dugan VG, Daskalakis DC. Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices — United States, 2025–26 Influenza Season. MMWR Morb Mortal Wkly Rep. 2025;74(32):500-507. doi:10.15585/mmwr.mm7432a2
  3. Ask the experts: influenza: live attenuated influenza vaccine (LAIV) issues. Immunize.org. Accessed June 17, 2026. https://www.immunize.org/ask-experts/topic/influenza/laiv-issues/
  4. Vaccines and immunizations: Vaccine administration. Centers for Disease Control and Prevention. Accessed June 17, 2026. https://www.cdc.gov/vaccines/hcp/imz-best-practices/vaccine-administration.html?CDC_AAref_Val=https://www.cdc.gov/vaccines/hcp/acip-recs/general-recs/administration.html#cdc_report_pub_study_section_2-route-of-administration
  5. Data on File, REF-263898. AstraZeneca Pharmaceuticals LP.
  6. Key facts about seasonal flu vaccine. Centers for Disease Control and Prevention. Accessed June 17, 2026. https://www.cdc.gov/flu/vaccines/keyfacts.html?CDC_AAref_Val=https://www.cdc.gov/flu/prevent/keyfacts.htm
  7. Live attenuated influenza vaccine [LAIV] (the nasal spray flu vaccine). Centers for Disease Control and Prevention. Accessed June 17, 2026. https://www.cdc.gov/flu/vaccine-types/nasalspray.html?CDC_AAref_Val=https://www.cdc.gov/flu/prevent/nasalspray.htm
  8. Safety of influenza vaccines. Centers for Disease Control and Prevention. Accessed June 17, 2026. https://archive.cdc.gov/#/details?q=safety%20of%20influenza%20vaccines&start=0&rows=10&url=https://www.cdc.gov/flu/professionals/acip/safety-vaccines.htm
References:
  1. Preliminary estimated flu disease burden 2025-2026 flu season. Centers for Disease Control and Prevention. Accessed June 17, 2026. https://www.cdc.gov/flu-burden/php/php/data-vis/2025-2026.html
  2. Flu burden prevented by vaccination. Centers for Disease Control and Prevention. Accessed June 17, 2026. https://www.cdc.gov/flu-burden/php/data-vis-vac/index.html
  3. Healthy People 2030. Increase the proportion of people who get the flu vaccine every year—IID-09. Office of Disease Prevention and Health Promotion, US Dept of Health and Human Services. Accessed June 17, 2026. https://health.gov/healthypeople/objectives-and-data/browse-objectives/vaccination/increase-proportion-people-who-get-flu-vaccine-every-year-iid-09
  4. Influenza vaccination coverage, children 6 months through 17 years, United States. Centers for Disease Control and Prevention. Accessed June 17, 2026. https://www.cdc.gov/fluvaxview/dashboard/children-vaccination-coverage.html
  5. Influenza vaccination coverage and intent for vaccination, adults 18 years and older, United States. Centers for Disease Control and Prevention. Accessed June 17, 2026. https://www.cdc.gov/fluvaxview/dashboard/adult-coverage.html
  6. Newall M, Morris C. Expanding flu vaccine. Ipsos. Accessed June 17, 2026. https://www.ipsos.com/en-us/news-polls/expanding-flu-vaccine
  7. Clinical guidance for influenza vaccination. Centers for Disease Control and Prevention. Accessed June 17, 2026. https://www.cdc.gov/flu/hcp/vax-summary/?CDC_AAref_Val=https://www.cdc.gov/flu/professionals/vaccination/vax-summary.htm
Reference:
  1. FLUMIST Prescribing Information.

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