Flu season is here, and so are new recommendations from the ACIP

By Liz Meszaros, MDLinx
Published September 11, 2018

Key Takeaways

It’s almost that magical time of the year again—flu season. In anticipation, the Centers for Disease Control and Prevention (CDC) Advisory Committee on Immunization Practices (ACIP) has released updated recommendations for the prevention and control of seasonal influenza with vaccines for the upcoming 2018-2019 season.

According to Morbidity and Mortality Weekly Report, the 2017-2018 flu season was one of the most severe and was dominated by the A(H3N2) virus, the most lethal of the seasonal strains. A record number of hospitalizations and a high number of influenza-associated pediatric deaths occurred.

In gearing up for the new season, ACIP recommends annual influenza vaccination for all individuals aged 6 months or older who have no contraindications. If possible, vaccinations should be given by the end of October.

During three public meetings that ACIP began holding regularly in October 2017, new and updated recommendations for the 2018-2019 season were hammered out and include:

  1. The 2018-2019 trivalent influenza vaccine will include the following vaccine viruses: 
    • An A/Michigan/45/2015 (H1N1) pdm09-like virus
    • An A/Singapore/INFIMH-16-0019/2016 (H3N2)-like virus
    • A B/Colorado/06/2017-like virus (Victoria lineage)

The quadrivalent influenza vaccine will contain all three of these viruses and an additional influenza B vaccine virus: a B/Phuket/3073/2013-like virus (Yamagata lineage).

  1. Changing their recommendations from the previous two flu seasons, ACIP now recommends live-attenuated influenza vaccine (LAIV4; FluMist Quadrivalent)—delivered as a nasal spray—as an option for patients for whom it is appropriate. This recommendation was based on new data showing that the 2017-2018 H1N1 LAIV postpandemic strain performed significantly better than the 2015-2016 strain. They specified that providers can choose any licensed, age-appropriate influenza vaccine, including influenza-inactivated vaccine (IIV), quadrivalent, recombinant vaccine (RIV4), or live-attenuated influenza vaccine (LAIV4).
  2. Patients with a history of egg allergy of any grade can receive any licensed, recommended, and age-appropriate influenza vaccine (IIV, RIV4, or LAIV4). Recommendations on vaccinating egg-allergic patients were also detailed.
  3. Recent licensures and labeling changes include a broadening of the age indication for Fluarix Quadrivalent (IIV4) vaccine, which had previously been licensed for children 3 years or older, to those 6 months or older; and an expansion of the age indication for Afluria Quadrivalent (IIV4) from those aged 18 years and older to those aged 5 years or older.

More information is available at the CDC’s website, and health-care providers are advised to check the website periodically for more information.

Immune-boosting cream tested

In related influenza vaccine news, researchers from Baylor College of Medicine, Houston, TX, report that they have begun a double-blind, phase 1 clinical trial to assess the efficacy of a topical cream in enhancing the immune response caused by a “prepandemic” influenza vaccine for H5N1.

H5N1 is an avian influenza virus that causes severe respiratory illness in birds but is rarely contracted by humans from direct or indirect contact with infected birds. In humans, infection with H5N1 can be serious and deadly. From 2003 through July 2018, the World Health Organization reported 860 cases of H5N1 influenza in humans, 454 of which were fatal. Although H5N1 is not easily spread between people, it could possibly evolve to be more contagious, and has pandemic potential.

For this study, the topical cream that researchers are testing will contain imiquimod, a synthetic imidazoquinolone amine commonly used to treat genital warts and certain skin cancers, especially cutaneous malignancies. Used topically, imiquimod exhibits a potent immune response modifier activity.

Subjects will receive two intradermal doses of the H5N1 vaccine, an inactivated vaccine manufactured by Sanofi Pasteur and approved by the US Food and Drug Administration in 2007 for use in a potential pandemic. They will be randomized to receive either imiquimod cream applied to the upper arm before each vaccination (spaced 21 days apart) or placebo, and instructed not to wash for 4 to 6 hours. Subjects will return regularly for serum testing for 7 months to assess their immune responses.

The first subject was vaccinated on June 19, 2018, and researchers expect to have preliminary results by the end of 2018.

Two previous studies by researchers in Hong Kong assessed the efficacy of imiquimod cream and seasonal inactivated influenza vaccine. One trial was done in elderly subjects, and the other in young adults. Results showed that imiquimod cream was generally well tolerated, and subjects using the cream before they were vaccinated generated significantly more robust immune responses than control subjects who did not receive the cream.

This current study is supported by the National Institute of Allergy and Infectious Diseases (NIAID), which is part of the National Institutes of Health (NIH). The potential immune-boosting properties of imiquimod may help stretch the supply of H5N1 vaccines by reducing the number of doses required to achieve sufficient immunity. In case of an outbreak, this boost would allow for more people to be vaccinated.

“NIAID is pleased to support a clinical trial evaluating an innovative way to boost immune responses to a prepandemic vaccine,” said Anthony S. Fauci, MD, NIAID Director. “The Vaccine and Treatment Evaluation Units remain a crucial component of our pandemic influenza preparedness efforts.”

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