What Are the Latest Influenza Vaccine Recommendations?

This article was updated October 24, 2019.

Clinicians should recommend routine yearly influenza vaccinations for everyone 6 months or older who has no contraindications for the 2019-2020 influenza season starting at the end of October, according to the Advisory Committee on Immunization Practices.¹

In older adults, vaccinating earlier may result in lower immunity before the season ends.

Children aged 6 months through 8 years who need 2 doses should get their first dose as early as possible so that they can receive the second dose 4 weeks later.

High-Risk Populations

Populations that are considered at risk include¹:

• Adults and children with chronic disease, including cardiovascular (excluding isolated hypertension), chronic pulmonary (including asthma), hematologic, hepatic, metabolic disorders (including diabetes mellitus), neurologic, or renal, American Indians or Alaska natives
• Anyone in a long-term-care facility
• Children aged 6 through 59 months
• Children and adolescents aged 6 months through 18 years who have a higher risk for Reye syndrome after influenza virus infection, because they are taking aspirin- or salicylate-containing medications
• Immunocompromised individuals
• Individuals who are 50 or older
• Individuals who care for or live with high-risk individuals, such as health care workers or those who work in a nonmedical capacity in health care facilities
• People who are extremely obese, with a body mass index of ≥40 for adults
• Women who are or who expect to be pregnant during influenza season

Individuals with a known egg allergy or previous reaction to eggs may receive any licensed, recommended influenza vaccine. Live vaccines are not recommended for immunocompromised or pregnant patients. Clinicians should use precautions in patients who have a history of Guillain-Barré syndrome within 6 weeks of receiving any type of influenza.

Influenza Vaccination Types

Influenza vaccines are either trivalent, which contain 2 influenza A antigens and 1 influenza B antigen, or quadrivalent which contain 2 influenza A and influenza B antigens. There are several types of influenza vaccines available, including inactivated influenza vaccines (IIVs), one recombinant influenza vaccine, Flublok Quadrivalent (RIV4) and a live attenuated vaccine (LAIV). There are several standard-dose IIV products, which are all quadrivalent and many of which are licensed for those as young 6 months of age. There is 1 high-dose trivalent IIV and 1 adjuvanted trivalent IIV, both of which are recommended for those aged ≥65 years.

Although the CDC recommends annual influenza vaccination for everyone 6 months and older with any age-appropriate, licensed flu vaccine there are certain conditions where specific vaccines types may be preferable.²

Most vaccines are administered intramuscularly in the deltoid muscle, with the exception of the quadrivalent egg-grown live-attenuated influenza vaccine, which is administered via intranasal spray.

For most patients 1 dose of the intramuscular quadrivalent inactivated vaccine is preferred and should be administered annually before the onset of flu season. Needle-phobic adult patients can receive either trivalent inactivated influenza vaccine (Afluria) using a jet injector device, or healthy, nonpregnant adults up to 50 years of age can receive LAIV. Patients who are 65 or older should receive the intramuscular high-dose trivalent inactivated influenza vaccine (Fluzone High-Dose).³The high-dose influenza vaccine is more effective than standard-dose vaccines but is more expensive and has an increased rate of adverse effects. Additionally, the standard-dose influenza vaccines may be less effective in older patients taking statin medications.⁴

Influenza vaccines are generally well-tolerated. The most common adverse effect is temporary arm soreness at the injection site. The high-dose influenza vaccine is associated with a higher incidence of mild-to-moderate local reactions compared with the standard-dose vaccine. The most common adverse effects of the intranasal LAIV are nasal congestion and rhinorrhea.¹

Contraindications to influenza vaccination depend on the type of vaccine administered. Any history of severe allergic reaction, such as anaphylaxis, to an influenza vaccine is a contraindication to all types of vaccines.

The effectiveness of flu vaccines varies significantly from season to season and depends on several host and viral factors. Studies from flu seasons 2017-2018 and 2018-2019 demonstrate vaccine efficacy of about 38% and 29%, respectively.^5,6In addition to reducing the risk of influenza illness, vaccination can protect children, patients with chronic illness, and pregnant women from hospitalization and serious illness.¹

Antiviral Medications

Antiviral drugs can lessen symptoms and shorten the time of sickness by 1 or 2 days. They also can prevent serious flu complications, such as pneumonia. The CDC recommends prompt treatment for people who have influenza infection or suspected influenza infection and who are at high risk of serious flu complications.

There are 4 FDA-approved medications approved for the 2019-2020 flu season¹:

1.Baloxavir marboxil (Xofluza)is a new antiviral drug approved in 2018 for the treatment of seasonal influenza in patients who have been symptomatic for 48 hours or less. Patients 12 years and older who weigh 40-79.9 kg dose 40 mg PO x1. Patients > 80 kg dose 80 mg PO x1. This drug is contraindicated in pregnancy and breastfeeding. October 2019 Xofluza became the first and only FDA-approved treatment option indicated specifically for those at high risk of flu complications. This includes patients with conditions such as asthma, COPD, diabetes, heart disease, morbidly obese and 65 years or older. Side effects occur in < 1% of patients and include diarrhea, bronchitis, nausea, sinusitis and headache.

2. Oseltamivir phosphate (generic version or trade name Tamiflu) is available as a liquid suspension or pill and is FDA-approved for early treatment of flu in people 14 days and older.

3. Peramivir (Rapivab), is given intravenously by a health care provider and is approved for early treatment of flu in people 2 years and older.

4. Zanamivir (Relenza) is a powder that is inhaled and approved for early treatment of flu in people 7 years and older. It is administered using an inhaler device and is not recommended for those with breathing problems, such as asthma or chronic obstructive pulmonary disorder.

Clinicians must keep in mind that the best treatment for flu is prevention. It is the health care provider’s responsibility to recommend the flu vaccine to all patients 6 months or older and especially those considered high risk for flu complications.

Jennifer L. Hofmann, MS, PA-C, is a clinical associate professor and full-time faculty and pharmacology courses instructor at Pace University-Lenox Hill Hospital PA Program in New York, New York. She is also a PA program adjunct professor for the Touro College School of Health Sciences in Bayshore, New York, and Nassau University Medical Center in East Meadow, New York. In addition, she is a Stony Brook University PA Program postprofessional PA program clinical pharmacology seminar adjunct professor in New York.

Jean Covino, DHSc, PA-C, is a clinical professor at Pace University’s College of Health Professions in New York.

REFERENCES

1. Grohskopf LA, Alyanak E, Broder KR, Walter EB, Fry AM, Jernigan DB. Prevention and control of seasonal influenza with vaccines: recommendations of the advisory committee on immunization practices - United States, 2019—20 Influenza.MMWR Recomm Rep. 2019;68(3);1-21. doi: 10.15585/mmwr.rr6803a1.
2. CDC. Prevent seasonal flu.cdc.gov/flu/prevent/index.html. Updated September 19, 2019. Accessed September 22, 2019.
3. DiazGranados CA, Dunning AJ, Kimmel M, et al. Efficacy of high-dose versus standard-dose influenza vaccine in older adults.N Engl J Med.2014;371(7):635-645. doi: 10.1056/NEJMoa1315727.
4. Black S, Nicolay U, Del Giudice G, Rappuoli R. Influence of statins on influenza vaccine response in elderly individuals.J Infect Dis.2016;213(8):1224-1228. doi: 10.1093/infdis/jiv456.
5. Rolfes MA, Flannery B, Chung J, et al. Effects of influenza vaccination in the United States during the 2017—2018 influenza season.Clin Infect Dis.doi: 10.1093/cid/ciz075.
6. CDC. Preliminary estimates of 2018—19 seasonal influenza vaccine effectiveness against medically attended influenza from three U.S. networks.cdc.gov/vaccines/acip/meetings/downloads/slides-2019-06/flu-3-flannery-508.pdf. Published June 27, 2019. Accessed September 3, 2019.