Answering Questions About Influenza Vaccine Formulations for the 2014/2015 Season

For the 2014/2015 season, 13 types of influenza vaccine are currently available. Navigating the intricacies of specific formulations is of foremost importance to the community pharmacist.

With the 2014 influenza season at hand, it is important for pharmacists to be familiar with all of the available formulations of flu vaccine for the 2014/2015 season. In total, 13 vaccines are available, including intramuscular, intradermal, and intranasal vaccines.¹

This year, for the first time, a recombinant, albumin-free vaccine—FluBlok—is available for patients with severe egg allergies. In addition, patients now have a choice between trivalent and quadrivalent vaccines. Navigating the intricacies of specific formulations and ensuring that patients are treated appropriately is of foremost importance to the community pharmacist.^1,2

For ease of use, the information in this article is organized into the common questions that patients have about the flu vaccine.

Which vaccines contain mercury, and which do not?

Although some flu vaccines contain mercury (in the form of thimerosal), each dose of these vaccines contains about as much mercury as a tuna fish sandwich (calculation: 1 ounce of tuna × [29.6 g/1 ounce] × [1 g mercury/10⁶ grams tuna] × [1000 mg/1 g mercury] × [1000 mcg/1 mg mercury] = 29.6 mcg mercury). This amount of mercury does not pose a significant health threat.^1,3 A list of available vaccines for the 2014/2015 season that do and do not contain thimerosal follows¹:

All dosage forms are free of thimerosal:

• Fluarix Quadrivalent 0.5-mL single-dose prefilled syringe
• Fluarix 0.5-mL single-dose prefilled syringe
• Fluzone Intradermal 0.1-mL prefilled microinjection system
• Flucelvax 0.5-mL single-dose prefilled syringe
• Fluzone High-Dose 0.5-mL single-dose prefilled syringe
• FluBlok 0.5-mL single-dose vial
• FluMist Quadrivalent 0.2-mL single-dose prefilled intranasal sprayer

Some dosage forms are free of thimerosal:

• FluLaval 0.5-mL single-dose prefilled syringe (however, the 5.0-mL multidose vial does contain thimerosal)
• Fluzone 0.5-mL single-dose prefilled syringe (however, the 5.0-mL multidose vial does contain thimerosal)
• FluLaval Quadrivalent 0.5-mL single-dose prefilled syringe (however, the 5.0-mL multidose vial does contain thimerosal)
• Fluzone Quadrivalent 0.25-mL single-dose prefilled syringe, 0.5-mL single-dose prefilled syringe, 0.5-mL single-dose vial (however, the 5.0-mL multidose vial does contain thimerosal)
• Afluria 0.5-mL single-dose prefilled syringe (however, the 5.0-mL multidose vial does contain thimerosal)

All formulations have thimerosal:

• All formulations of Fluvirin contain thimerosal, although the 0.5-mL single-dose prefilled syringe contains ≤1 mcg per 0.5-mL dose, while the 5.0-mL multidose vial contains 25 mcg per 0.5-mL dose

Which flu vaccines contain traces of albumin protein?

Only Flublok, an intramuscularly administered trivalent recombinant influenza vaccine, is completely free of egg protein. FluBlok is indicated for use in adults 18 to 49 years of age.¹

What should I know before receiving this vaccine?

The vaccine information statement (VIS) contains important information that should be given to patients receiving the flu vaccine. The VISs for the current season can be found at the following websites^6,7:

• Updated VIS for the intranasal influenza vaccine: www.cdc.gov/vaccines/hcp/vis/vis-statements/flulive.html
• Updated VIS for the inactivated influenza vaccine: www.cdc.gov/vaccines/hcp/vis/vis-statements/flu.html

What do the guidelines say about vaccination of immunocompromised patients?

The most up-to-date guidelines from the Infectious Disease Society of America, reviewed here, recommend administering an annual dose of the inactivated influenza vaccine for immunocompromised patients 6 months or older. However, patients receiving intensive chemotherapy and patients who have, within 6 months, received treatment with anti—B-cell antibodies (eg, rituximab, obinutuzumab, ofatumumab) may not derive any benefit from the vaccine due to high-level immunosuppression.⁸

Which specific flu strains are covered by the trivalent and quadrivalent influenza vaccines this year? Which vaccines contain H1N1?

All vaccines this year contain an antigen from the H1N1 strain.⁹

The trivalent vaccine contains⁹:

• Hemagglutinin (HA) from A/California/7/2009 (H1N1)-like virus A/Texas/50/2012 (H3N2)-like virus and B/Massachusetts/2/2012-like (Yamagata lineage) virus

The quadrivalent vaccine contains an additional strain⁹:

• B/Brisbane/60/2008-like (Victoria lineage) virus

Should I receive the high-dose vaccine (patients 65 years or older)?

This year, for this first time, researchers have proved superior efficacy of the trivalent high-dose influenza vaccine in seniors. Results of the 31,989-participant 126-center study, which were published in an August 2014 issue of the The New England Journal of Medicine, demonstrated a significantly greater preventive benefit with the Fluzone high-dose vaccine versus the standard vaccine in patients 65 years or older. Approximately 1 in 4 breakthrough cases of influenza that occur after administration of the standard vaccine can be prevented among seniors who receive the high-dose vaccine.^10,11

Where can I get more information?

Please see the Centers for Disease Control and Prevention’s information on the 2014/2015 flu season at www.cdc.gov/flu/about/season.¹²

References:

1. Centers for Disease Control and Prevention. Influenza vaccines—United States, 2014—15 influenza season. www.cdc.gov/flu/protect/vaccine/vaccines.htm. Published August 14, 2014. Accessed September 4, 2014.

2. Flublok (influenza vaccine) [package insert]. Meriden, CT: Protein Sciences Corporation; 2014.

3. FDA. Mercury levels in commercial fish and shellfish (1990-2010). www.fda.gov/Food/FoodborneIllnessContaminants/Metals/ucm115644.htm. Accessed September 4, 2014.

4. Fluzone intradermal vaccine administration video. www.fluzone.com. Accessed September 4, 2014.

5. Fluzone intradermal user guide. www.fluzone.com. Accessed September 4, 2014.

6. Center for Disease Control and Prevention. Updated VIS for the intranasal influenza vaccine. www.cdc.gov/vaccines/hcp/vis/vis-statements/flulive.html. Accessed September 4, 2014.

7. Center for Disease Control and Prevention. Updated VIS for the inactivated influenza vaccine. www.cdc.gov/vaccines/hcp/vis/vis-statements/flu.html. Accessed September 4, 2014.

8. Rubin LG, Levin MJ, Ljungman P, et al. 2013 IDSA clinical practice guideline for vaccination of the immunocompromised host. Clin Infect Dis. 2014;58(3):309-318.

9. Grohskopf LA, Olsen SJ, Sokolow LZ, et al. Prevention and control of seasonal influenza with vaccines: recommendations of the advisory committee on immunization practices (ACIP)—United States, 2014-15 Influenza Season. MMWR Morb Mortal Wkly Rep. 2014;63(32):691-697.

10. Boerner C. Vanderbilt University. High-dose flu vaccine more effective in elderly, Vanderbilt-led study shows. http://news.vanderbilt.edu/2014/08/high-dose-flu-vaccine-more-effective-in-elderly/. Accessed August 2014.

11. DiazGranados CA, Dunning AJ, Kimmel M, et al. Efficacy of high-dose versus standard-dose influenza vaccine in older adults. N Engl J Med. 2014;371(7):635-645.

12. Center for Disease Control and Prevention. 2014-2015 Flu season. www.cdc.gov/flu/about/season. Accessed September 4, 2014.