Nasal Spray Flu Vaccine Ineffective and Not Recommended Interview with:

Michael Jackson  PhD, MPH Kaiser Permanente Washington Health Research Institute (KPWHRI) principal investigator for the United States Influenza Vaccine Effectiveness Network

Dr. Jackson

Michael Jackson  PhD, MPH
Kaiser Permanente Washington Health Research Institute (KPWHRI) principal investigator for the United States Influenza Vaccine Effectiveness Network What is the background for this study?

  • Response: Each year, Kaiser Permanente Washington is one of five sites across the country that participate in the United States Influenza Vaccine Effectiveness Network. The Network reports its early interim results in the MMWRand presents additional interim results to the Advisory Committee on Immunization Practices (ACIP)This New England Journal of Medicine publication is an update of those interim results.
  • The findings in this New England Journal of Medicine are special because prior randomized controlled trials indicated that the nasal spray vaccine (FluMist)—also called live attenuated influenza vaccine (LAIV)—would work well to protect children and teens from the flu, whereas in actual practice we found that the flu shot worked much better, particularly against the predominant strain, A(H1N1)pdm09.
  • The nasal spray vaccine was first seen to be less effective for young children than the flu shot in 2013-2014 for the A(H1N1)pdm09 virus strain. In response, the A(H1N1)pdm09 virus strain used in the nasal spray vaccine was changed for the 2015-2016 influenza season. The 2016/17 season was the first since 2015-2016 to be dominated by the A(H1N1)pdm09 virus, making this our first opportunity to evaluate the updated nasal spray vaccine.
  • The Influenza Vaccine Effectiveness Network evaluated the impact of this change as part of our estimates of influenza vaccine effectiveness in 2015-2016. Preliminary findings from this study were presented to the ACIP in June 2016, which led to the nasal spray vaccine not being recommended in 2016-2017 in the US, although the nasal spray vaccine remains licensed in the US. In 2016-2017, the LAIV A(H1N1)pdm09 vaccine strain was unchanged from 2015-2016. What are the main findings?

  • Overall flu vaccine effectiveness (VE) was about 48% during the 2015-2016 season.
  • For the inactivated influenza vaccine (the flu shot), among children age 2-17 years:
    • VE against all influenza viruses for the flu shot was 60%.
    • VE against H1N1 for the flu shot was 63%.
    • VE against influenza B viruses for the flu shot was 54%.
    • These findings are comparable to past estimates for seasons when most circulating flu viruses and vaccine viruses have been similar.
  • By contrast, vaccine effectiveness for LAIV (the nasal spray vaccine) was poor.

o   Among children 2-17 years of age, LAIV was not observed to be effective (VE 5%).

o   In particular, LAIV offered no significant protection against the predominant flu virus [i.e., influenza A (H1N1)pdm09].

o   It also offered no significant protection against influenza B viruses. What should readers take away from your report?

  • We found that the problems with the nasal spray vaccine seen in 2013/14 were not fixed by updating the A(H1N1)pdm strain. The nasal spray vaccine still showed inferior performance to the flu shot in children.
  • The best protection against flu is to get yourself, and your children, vaccinated.
  • In addition to getting vaccinated, it is important to take all measure possible to prevent flu including:  frequently washing your hands, covering your cough, and avoiding others who have a respiratory illness. What recommendations do you have for future research as a result of this study?

Response: We found that IIV4 was significantly more effective than IIV3 against B/Victoria viruses, which were not included in the 2015-2016 trivalent vaccine. In some prior seasons, IIV3 has been seen to protect against both B lineages. Our finding of superior vaccine effectiveness of IIV4 relative to IIV3 against B/Victoria suggests that switching to IIV4 may prevent additional cases of influenza B relative to IIV3 during some seasons. But this idea needs to be tested.


Disclosure forms provided by the authors will be available with the full text of the article at

  • Edward A. Belongia, Manjusha Gaglani, and Huong Q. McLean have received research funds from MedImmune, LLC.
  • Emily T. Martin, Mary Patricia Nowalk, and Richard Zimmerman have received research funds from Merck & Co., Inc.
  • Lisa A. Jackson has received research funds from Novavax.
  • Emily T. Martin has received research funds from the Multiparty Group for Advice on Science.
  • Arnold S. Monto and Richard Zimmerman have received research funds from Sanofi Pasteur, Inc.
  • Arnold S. Monto has received personal fees from Novartis and Protein Sciences Corporation.
  • Richard Zimmerman, Emily T. Martin, and Mary Patricia Nowalk have received research funds from Pfizer Inc.
  • The remaining authors report no conflicts of interest. Thank you for your contribution to the community.

Citation: Influenza Vaccine Effectiveness in the United States during the 2015–2016 Season

Michael L. Jackson, Ph.D., Jessie R. Chung, M.P.H., Lisa A. Jackson, M.D., C. Hallie Phillips, M.Ed., Joyce Benoit, B.S.N., Arnold S. Monto, M.D., Emily T. Martin, Ph.D., Edward A. Belongia, M.D., Huong Q. McLean, Ph.D., Manjusha Gaglani, M.D., Kempapura Murthy, M.P.H., Richard Zimmerman, M.D., Mary P. Nowalk, Ph.D., Alicia M. Fry, M.D., and Brendan Flannery, Ph.D.

N Engl J Med 2017; 377:534-543August 10, 2017DOI: 10.1056/NEJMoa1700153

Note: Content is Not intended as medical advice. Please consult your health care provider regarding your specific medical condition and questions.


[wysija_form id=”5″]






Last Updated on October 18, 2017 by Marie Benz MD FAAD