By Haley Grunwald, PharmD and Talia Papiro, PharmD
Reviewed by Bernard Lee, PharmD, BCPS, BCPPS and Elizabeth Boucher, PharmD, BCPS, BCPPS
With the 2016-2017 influenza season approaching it is important for healthcare providers to be aware of recent changes per the Center for Disease Control and Prevention (CDC) regarding the use of FluMist Quadrivalent®. FluMist® is a live attenuated influenza vaccine (LAIV) administered intranasally, compared to inactivated influenza vaccines (IIV) which are given by intramuscular or intradermal injection. Recommendations from the CDC’s Advisory Committee on Immunization Practices (ACIP) regarding the use of FluMist® have changed from season to season, leading to potential confusion amongst providers regarding its place in current immunization practices. This article includes a history of vaccine effectiveness over the past few years, a discussion of the controversy surrounding FluMist®, and a summary of current recommendations for the 2016-2017 influenza season.
Figure 1. Timeline of the CDC’s recommendations over the recent years.
Data from the U.S. Influenza Vaccine Effectiveness Network provided evidence that children between the ages of 2 and 17 had similar risk of influenza despite vaccination with LAIV or IIV from the 2010-2013 seasons. The risk of acquiring influenza was shown to be greater in children vaccinated with LAIV during 2013-2014, which was largely attributed to “reduced stability and infectivity of the A/California/2009/(H1N1) vaccine virus conferred by a single amino acid mutation”. Analysis of data from the 2014-2015 season depicted lack of significant protection from either vaccine, LAIV or IIV, in children. It was this data that prompted ACIP to change its recommendations this past year to eliminate a preference of LAIV over IIV within this patient population. In the 2015-2016 season, the stability concerns surrounding the aforementioned H1N1 strand were addressed by including a different influenza A (H1N1) virus as part of the make-up of the vaccine. Despite the change to the vaccine make-up, data from the U.S. Influenza Vaccine Effectiveness Network evaluating vaccine effectiveness throughout the 2015-2016 season, showed no significant effectiveness among children for influenza viruses (3%, 95% CI = -49 – 37). Similar results were presented by an unpublished Department of Defense analysis discussed in CDC reports. MedImmune presented data at the June 2016 ACIP meeting estimating a higher vaccine effectiveness of 50%, but results were not statistically significant. In contrast, the effectiveness of IIV was noted to be significant in each of the studies. Of note, while the earlier ineffectiveness was thought to be due to an amino acid mutation, the reason for the recent poor performance is unknown. Figure 1 describes the timeline of the CDC’s recommendations based on the data reviewed in this section.
In a press release by AstraZeneca, data was presented that contrasts with findings from the CDC effectiveness data. A multi-center case control study in the United Kingdom reported vaccine effectiveness of LAIV as 57.6% (95% CI 25.1-76) in children between the ages of 2 and 17 years from October 2015-May 2016. FluMist® is currently the only non-injection-based influenza vaccine on the market making it particularly appealing to pediatric patients who have an aversion to the potentially painful intramuscular injections. The product’s popularity within the pediatric community is quantified by recent data that suggests that LAIV accounts for about one third of all flu vaccines given to children. Due to its widespread use in previous seasons, the makers of LAIV had projected a supply of 14 million doses of LAIV for the 2016-2017 season. In the aforementioned press release by AstraZeneca it was revealed that, “US Product Sales of FluMist Quadrivalent® in FY 2015 amounted to $206 million.” As a result of the recent CDC recommendation, the company expects to take an inventory markdown of approximately $80 million. AstraZeneca reports that distribution and use of FluMist Quadrivalent® will continue as planned in other countries for the 2016-2017 season and that the company is working with the CDC to evaluate current data to ensure use of LAIV in the future.
Based on these vaccine effectiveness findings, ACIP recommends that the live attenuated influenza vaccine “should not be used during the 2016-2017 season”.4 This recommendation coincides with those of the American Academy of Pediatrics, which were released early in September.5 While FluMist® is no longer recommended by the CDC, it remains a licensed vaccine that will be available on the market. ACIP recommendations state that “should LAIV be available, providers who elect to use it should consider previous guidance for use of LAIV4”. Institutional and community pharmacies alike should take these advisories into consideration when planning and preparing their influenza vaccine inventories for the upcoming flu season. Finally, the CDC addressed situations in which FluMist® might be the only option for a patient, by providing the recommendation that, “vaccination should not be delayed in order to obtain a specific product when an appropriate one is already available”. Yearly vaccination with inactivated influenza vaccine for children greater than 6 months of age, should continue.
- Grohskopf LA, Sokolow LZ, Broder KR, et al. Prevention and Control of Seasonal Influenza with Vaccines. MMWR Recomm Rep. 2016;65(5):1-54.
- Crawford, Chris. “ACIP: Don’t Use LAIV During 2016-2017 Flu Season” American Academy of Family Physicians. (2016). Retrieved from
- AstraZeneca. (2016). AstraZeneca provides update on Flumist Quadrivalent Vaccine in the US for the 2016-2017 influenza season [Press release]. Retrieved from https://www.astrazeneca.com/media-centre/press-releases/2016/astrazeneca-provides-update-on-flumist-quadrivalent-vaccine-in-the-us-for-the-2016-17-influenza-season-23062016.html
- Centers for Disease Control and Prevention. (2016). ACIP votes down use of LAIV for 2016-2017 flu season [Press release]. Retrieved from http://www.cdc.gov/media/releases/2016/s0622-laiv-flu.html
- American Academy of Pediatrics. (2016). AAP Issues Flu Vaccine Recommendations for 2016-17 Season [Press release]. Retrieved from https://www.aap.org/en-us/about-the-aap/aap-press-room/Pages/AAP-Issues-Flu-Vaccine-Recommendations-for-2016-17-Season.aspx