Flu Vaccine Only 39% Effective This Past Season, CDC Panel Says

The influenza vaccine was 39% effective against medically attended influenza for the 2019-2020 flu season; it offered lower protection against A/H1N1pmd09 virus 31%) compared with previous seasons but was 44% effective against B/Victoria virus, according to information presented June 24 at a meeting of the Advisory Committee on Immunization Practices (ACIP), Centers for Disease Control and Prevention (CDC).

The committee voted unanimously (14 yes, 0 no) to accept changes to the influenza vaccine for the 2020-2021 season.

The advisory committee also voted unanimously (14 yes, 0 no) to include the recently approved meningococcal ACWY-TT (MenQuadfi, Sanofi) in the Vaccines for Children program as an option for meningococcal ACWY immunization in accordance with current recommendations for dosing and schedules. The vaccine should only be administered to those aged 2 years and older (licensed age groups).

The committee did not vote on any changes to meningococcal vaccine dosing or schedules.

Changes in Flu Vaccines for Upcoming Season

Egg-based influenza vaccines during the 2020-2021 season will contain hemagglutinin derived from an A/Guangdong-Maonan/SWL1536/2019 (H1N1)pdm09-like virus; an A/Hong Kong/2671/2019 (H3N2)-like virus; and a B/Washington/02/2019 (Victoria lineage)-like virus. These are all changes this year. Quadrivalent vaccines will continue to also contain a B/Phuket/3073/2013 (Yamagata lineage)-like virus.

Non-egg–based influenza vaccines will contain hemagglutinin derived from an A/Hawaii/70/2019 (H1N1)pdm09-like virus; an A/Hong Kong/45/2019 (H3N2)-like virus; and a B/Washington/02/2019 (Victoria lineage)-like virus. Quadrivalent vaccines will continue to also contain a B/Phuket/3073/2013 (Yamagata lineage)-like virus.

Other updates include changes to Table 2 in the vaccine recommendations for influenza vaccines. The header "Contraindications and conditions for which use is not recommended" will be changed to "Contraindications." This table will include additional details about "which contraindications are labeled contraindications in the package insert, and which are ACIP recommendations," according to information presented at the meeting.

Asplenia, cochlear implant, and active cerebrospinal fluid leak are now included as contraindications in Table 2.

Guidance has been updated for LAIV4 and influenza antivirals on the basis of the various agents' half-lives and language regarding vaccination of individuals with egg allergy will be updated "to reflect availability of egg-free vaccines."

The recommendation that all persons aged 6 months and older who have no contraindications receive an annual influenza vaccine is unchanged for the 2020-2021 influenza season.

Regarding US influenza vaccine viral composition, two recently licensed vaccines will now be included: Fluzone High-Dose Quadrivalent (Sanofi Pasteur) and Fluad Quadrivalent (Seqirus).

Meningococcal Vaccines

"Meningococcal disease is a serious infection that can progress rapidly," Lucy McNamara, PhD, of the CDC, said during the meeting.

"One in 10 patients die despite antibiotic treatment, and among survivors, one in five have long-term sequelae, which can include hearing loss, amputation, and cognitive deficit," she added.

The US Food and Drug Administration approved the MenACWY-TT vaccine for use in individuals aged 2 years and older on April 24, 2020.

"The incidence of meningococcal disease is at an all-time low in the United States, with 0.10 cases per 100,000 population in 2018. Serogroups C, W, and Y combined currently account for approximately 50% of all cases," McNamara explained.

The committee's work group believes it is important for public health to include the MenACWY-TT vaccine in the Vaccines for Children program as the vaccine was recently licensed and doing so would strengthen the security of the vaccine supply, she noted in her presentation.

The work group determined that the vaccine's positive effects probably outweigh its risks in most settings.

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