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# FDA Keeps Flumist on Market Despite CDC Concerns
- URL: https://www.fdaweb.com/fda-keeps-flumist-on-market-despite-cdc-concerns/
- Published: 2016-06-28T12:00:00.000Z
- Updated: 2026-09-14T21:12:04.000Z
- Author: David McFarland
- Tags: Biologics, #legacy-id-D5136074

Despite a recommendation by a CDC panel that MedImmune’s FluMist live attenuated influenza vaccine should not be used during the 2016-2017 flu season because new preliminary data questioned its effectiveness rate, FDA says it has decided to leave the product on the market and no further regulatory action is warranted at this time. It appears the agency was blindsided ([see earlier story](https://www.fdaweb.com/blindsided-fda-ponders-cdcs-ineffective-rating-of-flumist/)) last week when CDC said flu shots should be used from now on instead of FluMist. At the time, FDA spokeswoman **Tara Goodin** was non-committal, saying in an email response: “Right now, we are reviewing the committee’s recommendations as we consider all options moving forward.”

In a just-posted [notice](http://www.fda.gov/BiologicsBloodVaccines/Vaccines/ApprovedProducts/ucm508761.htm?ref=fdaweb.com), FDA now says its decision to allow Flumist’s continued marketing is based on the agency’s review of manufacturing and clinical data supporting the original licensure, the totality of the evidence presented at the CDC panel meeting, taking into account the inherent limitations of observational studies conducted to evaluate influenza vaccine effectiveness, as well as the well-known variability of influenza vaccine effectiveness across influenza seasons. “FDA continues to work closely with MedImmune to determine the cause of the lower than expected effectiveness of FluMist Quadrivalent observed in recent years,” it says.

FDA’s notice says that three studies that CDC reviewed “showed statistically significant effectiveness of FluMist Quadrivalent against all influenza strains combined, ranging from 46% to 58% effectiveness. This level of overall effectiveness is comparable to vaccine effectiveness against vaccine-similar strains obtained from observational studies in children for both FluMist and inactivated influenza vaccines in prior seasons.” In contrast, it says, a fourth study conducted by CDC did not show statistically significant effectiveness of FluMist Quadrivalent for all influenza strains combined. “Reasons for discordant results among the studies, particularly between the two U.S. studies, are not clear but may include limitations inherent in observational study designs,” it says.