On June 22, 2016, the Centers for Disease Control and Prevention’s (CDC) Advisory Committee on Immunization Practices (ACIP) recommended against using the FluMist live virus nasal spray influenza vaccine, manufactured by AstraZeneca plc subsidiary MedImmune, LLC. The recommendation was based on the determination that FluMist was only three percent effective in protecting children two to 17 years of age against influenza and, thus, provided “no protective benefit.”1 2
Less than two years later, the ACIP reversed it decision on FluMist. On February 21, 2018, the panel voted to recommend FluMist for the 2018-2019 “flu season,” based on a new formulation of the vaccine by MedImmune. The company reportedly changed to a “new H1N1 strain (A/Slovenia) that is producing better antibody responses than the previous strain (A/Bolivia).”3 4 5
The problem is that there was no efficacy data available for the new formulation against H1N1, so it is not known how effective FluMist will be—whether it will be any better than three percent. The recommendation on FluMist is not based on scientific evidence, but rather more on hope. As staff writer Rishma Parpia of The Vaccine Reaction recently wrote, “News reports highlight that ACIP’s discussion was centered on giving FluMist another try.”3
The only thing that is certain and consistent about FluMist are its ingredients. While the H1N1 strain used in the vaccine has been reformulated, FluMist still contains monosodium glutamate (MSG), hydrolyzed porcine gelatin, arginine, sucrose, dibasic potassium phosphate, monobasic potassium phosphate, ovalbumin (OVA), gentamicin, ethylenediaminetetraacetic acid (EDTA).6 7 8 9
Most people are probably familiar with MSG. It is often used as a flavor enhancer in foods. Some individuals who are sensitive to the MSG can experience headaches (in some cases, severe), nausea, chest pain, facial pressure and numbness in the face or neck.7 Hydrolyzed porcine gelatin is a protein made from the boiled skin or connective tissue of pigs.7 10
Argenine, also known as L-arginine, is an amino acid, which is converted in the body into a chemical called nitric oxide. Nitric oxide causes blood vessels to expand. Argenine also stimulates the release of insulin.11 Sucrose is table sugar.
Dibasic potassium phosphate is “a highly water-soluble salt which is often used as a fertilizer, food additive and buffering agent.”12 Monobasic potassium phosphate is a “soluble salt of potassium and the dihydrogen phosphate ion which is used as a fertilizer, a good additive and a fungicide.”13
Gentamicin is an aminoglycoside antibiotic designed to treat bacterial infections.17
Since the vaccine is grown in chicken eggs, and eggs are not a sterile product, vaccine producers use gentamicin to decrease bacterial growth.7
The side effects of FluMist curiously enough include “mild flu-like symptoms” such as “headache, low fever, runny or stuffy nose, sore throat, cough, tiredness, fatigue, irritability, vomiting, muscle pain, chills, or achiness.” There may also be a loss of appetite and, on a rare occasion, anaphylactic shock.20 21
The good news is that, “just like the shot, the spray will not cause the flu.” That is the official line. Lots of “flu-like” symptoms, but not actual type A or B influenza itself.22
1 Centers for Disease Control and Prevention. ACIP votes down use of LAIV for 2016-2017 flu season. CDC.gov
2 Cáceres M. FluMist Nasal Spray Vaccine Doesn’t Work Says CDC Advisory Committee. The Vaccine Reaction July 6, 2016.
3 Parpia R. FluMist Vaccine Approved by CDC Without Proof It Works. The Vaccine Reaction Sept. 21, 2018.
4 CDC. Update: ACIP Recommendations for the Use of Quadrivalent Live Attenuated Influenza Vaccine (LAIV4) — United States, 2018–19 Influenza Season. Morbidity and Mortality Week Report June 8, 2018.
5 ACIP recommends LAIV for 2018-19 influenza season. Pharmacist.com Feb. 27, 2018.
6 Food and Drug Administration. FluMist Quadrivalent. FDA.gov.
7 Vaesa J. FluMist Ingredients: What’s In The Nasal Spray Influenza Vaccine? Decoded Science Jan. 28, 2013.
8 CDC. Vaccine Excipient & Media Summary. CDC.gov.
9 Cáceres M. Those Who Give Vaccines Should Know The Ingredients in Vaccines. The Vaccine Reaction Oct. 12, 2017.
10 Vaccines and porcine gelatine. NHS England.
11 L-arginine. WebMD.
12 National Institutes of Health. Dibasic Potassium Phosphate. NIH.gov.
13 Monopotassium phosphate. Wikipedia.
14 Ovalbumin. Wikipedia.
15 OVA Antigens. InvivoGen.
16 Ovalbumin. Fordras SA.
17 Gentamicin SULFATE Vial. WebMD.
18 Banfi G, Salvagno GL, Lippi G. The role of ethylenediamine tetraacetic acid (EDTA) as in vitro anticoagulant for diagnostic purposes. Clin Chem Lab Med 2007;45(5):565-76.
19 Taylor S. What is EDTA? Sciencing.com.
20 Cunha JP. FluMist. RxList.com.
21 Children’s flu vaccine side effects. NHS England.
22 What Is Nasal Spray Flu Vaccine? WebMD.