HealthOctober 07, 2019

What’s new with flu? Influenza vaccine updates for the 2019 season


Many providers and pharmacists are already well into influenza vaccination season, as they and the healthcare organizations for which they work have (rightly!) been encouraging patients to get vaccinated since early September (or even August).

As of September 28, 2019, the influenza activity nationally was still considered “low,” according to the Centers for Disease Control and Prevention (CDC).  Clinicians should check the CDC’s flu activity report weekly or every other week for up-to-date information about activity:

This page shows regional activity and contains reports of mortality related to influenza. It is important as healthcare providers that we stay informed on the status of influenza in the country and our region and that we encourage all appropriate patients to get vaccinated to help stop the spread of the virus.

2019 vaccinations: What and who?

According to CDC reports, this year’s available vaccines cover the following strains of influenza:

  • The trivalent vaccine (e.g., Fluad Seqirus, Fluzone high dose) contains:
    • A/Brisbane/02/2018 (H1N1)pdm09-like virus
    • A/Kansas/14/2017 (H3N2)-like virus
    • B/Colorado/06/2017-like (Victoria lineage) virus
  • The quadrivalent vaccine (e.g. Afluria quadrivalent, FluLaval quadrivalent, Fluarix quadrivalent, Flucelvax quadrivalent, and Fluzone quadrivalent) contains:
    • A/Brisbane/02/2018 (H1N1)pdm09-like virus
    • A/Kansas/14/2017 (H3N2)-like virus
    • B/Colorado/06/2017-like (Victoria lineage) virus
    • B/Phuket/3073/2013-like (Yamagata lineage) virus

“Flu shots” are widely encouraged and advertised to pharmacy-goers and patient populations en masse, but there are particular populations for whom you should stress the importance of receiving a vaccination this and every year:

  • All infants (6 months and older) and children under 5 years of age
  • All infants (6 months and older), children, and adolescents (aged 6 months through 18 years) who receive aspirin or salicylate-containing medications – these medications may increase risk of Reye syndrome after influenza virus infection
  • Anyone 50 years or older
  • Adults and children who have chronic pulmonary (including asthma), cardiovascular (excluding isolated hypertension), renal, hepatic, neurologic, hematologic, or metabolic disorders (including diabetes mellitus)
  • Immunocompromised patients (e.g., immunosuppression caused by medications or HIV infection or congenital deficiencies)
  • Women who are or will be pregnant during the influenza season
  • Residents of nursing homes and other long-term care facilities
  • American Indians/Alaska Natives
  • Extreme obesity patients (body mass index ≥40 for adults)
  • People who live with or care for others at high risk for influenza-related complications (e.g., healthcare personnel; household contacts of infants and children under 5 years, especially infants under 6 months; household contacts of adults over 50 years; household contacts of patients with severe medical conditions)

Among these groups, there are a few special populations to monitor:

Older adults are at increased risk for influenza-related complications such as pneumonia, hospitalization, even death. Everyone over the age of 50 should be vaccinated against influenza.  For people over 65 years of age, a high-dose influenza vaccine is available. In trials, it has shown to increase immune response to influenza and is more effective at preventing influenza compared to standard dose.  While initial trials suggest that this vaccine may be more effective, the most important thing is to have all elderly patients vaccinated regardless of the type of dose. The CDC does not recommend one vaccine over another at this time.

Pregnant and post-partum women are at increased risk for complications from influenza, especially during the second and third trimester. All pregnant women, or women who may become pregnant during flu season, should be vaccinated. Pregnant women should NOT receive the live intranasal vaccine.

Young children are at increased risk for complications for influenza-related illnesses. Infants over 6 months of age, children under 5 years of age, and American Indian or native Alaskan children are more likely to develop severe illnesses and should be vaccinated. When receiving an influenza vaccine (live or attenuated) for the first time, all children who are under 9 years of age should receive two doses approximately 28 days apart. The first dose “primes” the immune system to allow the second dose to provide better immunity. If the child has received the influenza vaccine the previous year, only one dose is necessary.

Dosing options

There are several dosing options available for this year’s vaccines.

Standard dose flu shots are quadrivalent vaccines manufactured with virus that is grown on eggs. Approval ages vary by manufacturer, however, this type can be given to patients 6 months of age and up unless there is a noted allergy to egg proteins

Live attenuated flu shot (e.g., Flumist) is a quadrivalent vaccine using attenuated live influenza virus. This is the only nasal administration option for immunization. It is approved for use in patients 2 years of age through age 49 who do not have other contraindications. More on this below!

High-dose flu shots (e.g. Fluzone high dose) are trivalent vaccines manufactured with virus grown on eggs. This vaccine has four times the amount of antigen compared to standard dose. High-dose shots are approved for use in patients 65 years and older.

Adjuvant flu shot (e.g., Fluad) is a trivalent vaccine manufactured with virus grown on eggs. This is a high-dose vaccine and has an added adjuvant (M59) to help produce a stronger immune reaction. It is approved for use in patients 65 years of age and up.

Recombinant flu shot (e.g., Flublock Quadrivalent) is a quadrivalent vaccine produced without chicken eggs or influenza virus. It does have a shorter shelf-life than other influenza vaccines – expiring 9 months after production. It is approved for use in patients 18 years of age and older.

Cell-culture flu shot (e.g. Flucelvax) is a quadrivalent vaccine produced on animal cell lines instead of chicken eggs. It is approved for use in patients 4 years of age and up.

The return of intranasal

Intranasal vaccines have been reintroduced with the 2019-2020 influenza vaccine recommendations. In prior years, it was not recommended due to concerns of reduced efficacy. The manufacturer has been working closely with the Advisory Committee on Immunization Practices (ACIP) and has updated the coverage strains. Based on efficacy data, live nasal vaccines have been approved for use for the 2019-2020 flu season. This is an available option for patients 2 years of age to 49 years of age.

Who should NOT get the live intranasal vaccines?

  • Children under 2 years
  • Children ages 2-4 who have asthma or who have had a history of wheezing in the past 12 months
  • Children ages 2-17 who are receiving aspirin- or salicylate-containing medications
  • Adults 50 years or older
  • Pregnant people
  • People with a history of severe allergic reaction to any component of the vaccine or to a previous dose of any influenza vaccine
  • Immunosuppressed patients or people with weakened immune systems
  • People who have taken influenza antiviral drugs within the previous 48 hours
  • People who care for severely immunocompromised persons who require a protected environment (unless they otherwise avoid contact with those persons for 7 days after getting the nasal spray vaccine)

A potential benefit to the return of the intranasal flu vaccine is its advantage in community immunization programs. Before intranasal vaccines were not recommended, they were often the preferred method in school-based and community-based vaccination programs, since they required fewer clinical staff and “squirts” were often quicker and easier to administer to hesitant or nervous patients than shots.

Whichever method or doses your organization prefers, the important thing is to make sure all eligible patients are encouraged to vaccinate for influenza and dosing is carefully reviewed for special and at-risk populations.

Darcie Streetman, PharmD, is a clinical pediatric pharmacist and Senior Clinical Editor for Neonatal and Pediatric Drug Information, Clinical Effectiveness, at Wolters Kluwer, Health. She attended Ohio Northern University, where she received her pharmacy degree. She then completed both a general practice residency and pediatric specialty residency at the University of Michigan.

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