Flu Vaccine Recommendations for the 2019-2020 Season

Although influenza seasons vary in severity, influenza can cause millions of illnesses, hundreds of thousands of hospitalizations, and tens of thousands of deaths worldwide each season. While not 100% effective, annual influenza vaccination offers important protection against influenza illness and its potential serious complications.

Hi. I'm Dr Lisa Grohskopf, a medical officer in the Influenza Division at the Centers for Disease Control and Prevention (CDC). For the 2019-2020 influenza season, CDC and the Advisory Committee on Immunization Practices (ACIP) continue to recommend routine annual influenza vaccination for all persons 6 months of age and older who do not have contraindications to vaccination. The full recommendations are available on the CDC website. Here are some of the key changes for the 2019-2020 season.

Vaccine Composition

This season, all US-licensed influenza vaccines will have changes in the influenza A(H1N1)pdm09 and influenza A(H3N2) vaccine virus components as compared with the 2018-2019 season. US-licensed trivalent influenza vaccines will contain hemagglutinin derived from A/H1N1, A/H3N2, and B/Victoria viruses. Quadrivalent influenza vaccines will contain hemagglutinin derived from these three vaccine viruses and from a B/Yamagata virus.

Trivalent Influenza Vaccine Composition: an A/Brisbane/02/2018 (H1N1)pdm09–like virus, an A/Kansas/14/2017 (H3N2)–like virus, and a B/Colorado/06/2017–like virus (Victoria lineage) Quadrivalent Influenza Vaccine Composition: The three recommended viruses above, plus B/Phuket/3073/2013-like (Yamagata lineage) virus

Recent Influenza Vaccine Labeling Changes

In the past year, the US Food and Drug Administration (FDA) has approved labeling changes for two influenza vaccines, Afluria Quadrivalent and Fluzone Quadrivalent.

In October 2018, the FDA approved an expanded age indication for Afluria Quadrivalent, a quadrivalent inactivated influenza vaccine. Afluria Quadrivalent is now licensed for children 6 months of age and older. Children 6 through 35 months of age should receive 0.25 mL for each dose. All persons 36 months (or 3 years) of age and older should receive 0.5 mL for each dose.

In January 2019, FDA approved a change in dose volume for Fluzone Quadrivalent, another quadrivalent inactivated influenza vaccine. The change in dose volume affects children 6 through 35 months of age. Previously, children in this age group were recommended to receive 0.25 mL of this vaccine per dose. Children 6 through 35 months of age may now receive either 0.25 mL or 0.5 mL per dose. There is no preference for one or the other dose volume for this age group. All persons 36 months (or 3 years) of age and older should receive 0.5 mL per dose.

One important thing to consider is that for children who are 6 through 35 months of age, there are now four different inactivated influenza vaccines that may be used, but the dose volumes for this age group differ depending on the specific vaccine. Care should be taken to administer an appropriate dose of an appropriate vaccine for the recipient's age. More information is in the table below:

Inactivated Influenza Vaccine Dosing for Children 6 Through 35 Months of Age Afluria Quadrivalent: 0.25 mL per dose (containing 7.5 µg of hemagglutinin per vaccine virus) Fluarix Quadrivalent: 0.5 mL per dose (containing 15 µg of hemagglutinin per vaccine virus) FluLaval Quadrivalent: 0.5 mL per dose (containing 15 µg of hemagglutinin per vaccine virus) Fluzone Quadrivalent: Either 0.25 mL per dose (containing 7.5 µg of hemagglutinin per vaccine virus) Or 0.5 mL per dose (containing 15 µg of hemagglutinin per vaccine virus)

Alternatively, healthy children 2 years of age and older may receive live attenuated influenza vaccine (LAIV4), 0.2 mL intranasally (0.1 mL in each nostril). LAIV4 is not licensed for children under 2 years of age.

Number of Influenza Vaccine Doses Needed for Children 6 Months Through 8 Years of Age

As in previous seasons, some children 6 months through 8 years of age will need two doses of influenza vaccine this season. Children in this age group who have not previously received two or more total doses of any trivalent or quadrivalent influenza vaccine (including LAIV) before July 1, 2019, or whose vaccination history is not known, need two doses of 2019-2020 influenza vaccine administered at least 4 weeks apart. For 8-year-olds who are determined to need two doses, the second dose is recommended even if the child turns 9 years of age between receipt of dose 1 and dose 2. Children in this age group who have received two or more total doses of trivalent or quadrivalent influenza vaccine before July 1, 2019, need only one dose for this season.

Timing of Vaccination

Because the timing of the onset, peak, and end of influenza seasons varies from year to year and cannot be predicted, it is difficult to know the best time to be vaccinated each season. Balancing this consideration with concerns for potential waning of vaccine-induced immunity during the influenza season, CDC and ACIP recommend that vaccination be offered by the end of October. Children 6 months through 8 years of age who need two doses should receive their first dose as soon as possible after the vaccine becomes available to allow the second dose (which must be administered at least 4 weeks later) to be received by the end of October. For people who need only one dose for the season, vaccinating early—for example, in July or August—may lead to reduced protection against influenza later in the season, particularly among older adults. While vaccination should optimally occur before the onset of influenza activity in the community, providers should continue to offer and encourage vaccination as long as influenza viruses are circulating and unexpired vaccine is available. To avoid missed opportunities for vaccination, vaccination can be offered during routine healthcare visits and hospitalizations.

Available Vaccines

Providers can administer any licensed influenza vaccine that is appropriate for the recipient's age and health status. Choices include inactivated, recombinant, or live attenuated influenza vaccines. Additionally, people 65 years of age and older may receive the trivalent influenza vaccine with adjuvant or the trivalent high-dose vaccine. No preferential recommendation is made for one influenza vaccine type over another, but efforts to assess effectiveness of different influenza vaccines for different populations continue.

Groups Recommended for Vaccination

For the 2019-2020 influenza season, the CDC and ACIP continue to recommend routine annual influenza vaccination for all persons 6 months of age and older who do not have contraindications to vaccination.

Vaccination to prevent influenza is particularly important for persons who are at increased risk for severe illness and complications from influenza. When vaccine supply is limited, vaccination efforts should focus on delivering vaccination to those groups most at risk for serious illness, such as young children, older adults, and people with chronic health problems. People who live with or care for those at higher risk for influenza-related complications should also be a focus for vaccination when vaccine supply is limited. You can find a full list of high-priority vaccination groups in the table below:

Priority Groups for Vaccination Children under 5 years of age (especially those under 2 years of age) Adults 65 years of age and older Adults and children who have chronic medical conditions such as chronic pulmonary (including asthma), cardiovascular (excluding isolated hypertension), renal, hepatic, neurologic, hematologic, or metabolic disorders (including diabetes mellitus) People who are immunocompromised (including, but not limited to, immunosuppression caused by medications or HIV infection) Pregnant and postpartum women Children and adolescents (aged 6 months through 18 years) who are receiving aspirin- or salicylate-containing medications Residents of nursing homes and other long-term care facilities American Indians/Alaska Natives People who are extremely obese (body mass index of 40 or greater for adults) Healthcare personnel Household contacts and caregivers of children under 5 years of age and adults 50 years of age and older Household contacts and caregivers of persons with medical conditions that put them at increased risk for severe illness and complications from influenza

I will close by reminding you about the importance of your role in protecting the public against influenza each season. Your recommendation to your patients that they receive the influenza vaccine is critical and more effective in increasing acceptance of vaccination than any other influencing factor. Healthcare providers should also lead by example and be sure that they themselves are vaccinated each and every season.

For more information, be sure to review the tables above and visit CDC's website.

Thank you for your attention.

Public Information from the CDC and Medscape

Cite this: Flu Vaccine Recommendations for the 2019-2020 Season - Medscape - Sep 24, 2019.