Seasonal Influenza Prevention & Control

Influenza Vaccine Updates

For the 2020-21 season, there is no preferential recommendation for any one flu vaccine over another. Read ACIP Updates Flu Vaccine Recommendations for 2020-2021: Report Includes Guidance for Patients With COVID-19 or review a summary of what’s different this season (2020-21):

• There is no preferential recommendation for any one flu vaccine over another.
  
• Routine annual influenza vaccination of all persons aged ≥6 months without contraindications continues to be recommended.
  
• The composition of the 2020–21 U.S. influenza vaccines includes updates to the influenza A(H1N1)pdm09, influenza A(H3N2), and influenza B/Victoria lineage components. These updated components will be included in both trivalent and quadrivalent vaccines. Quadrivalent vaccines will include an additional influenza B virus component from the B/Yamagata lineage, which is unchanged from that included in quadrivalent influenza vaccines used during the 2019–20 season. For the 2020–21 season, U.S. egg-based influenza vaccines (i.e., vaccines other than ccIIV4 and RIV4) will contain hemagglutinin (HA) derived from an influenza A/Guangdong-Maonan/SWL1536/2019 (H1N1)pdm09-like virus, an influenza A/Hong Kong/2671/2019 (H3N2)-like virus, an influenza B/Washington/02/2019 (Victoria lineage)-like virus, and (for quadrivalent egg-based vaccines) an influenza B/Phuket/3073/2013 (Yamagata lineage)-like virus. U.S. cell culture–based inactivated (ccIIV4) and recombinant (RIV4) influenza vaccines will contain HA derived from an influenza A/Hawaii/70/2019 (H1N1)pdm09-like virus, an influenza A/Hong Kong/45/2019 (H3N2)-like virus, an influenza B/Washington/02/2019 (Victoria lineage)-like virus, and an influenza B/Phuket/3073/2013 (Yamagata lineage)-like virus.
  
• Two new influenza vaccine licensures are described:
  

- In November 2019, FDA licensed Fluzone High-Dose Quadrivalent (HD-IIV4). Fluzone High-Dose Quadrivalent is approved for use in persons aged ≥65 years. For the 2020–21 season, Fluzone High-Dose Quadrivalent is expected to replace the previously available trivalent formulation of Fluzone High-Dose (HD-IIV3). The dose volume for Fluzone High-Dose Quadrivalent (0.7 mL) is slightly higher than that of trivalent Fluzone High-Dose (0.5 mL). Fluzone High-Dose Quadrivalent, like Fluzone High-Dose, contains 4 times the amount of HA per vaccine virus in each dose compared with standard-dose inactivated influenza vaccines (60 μg per virus, versus 15 μg in standard-dose IIVs).

- In February 2020, FDA licensed Fluad Quadrivalent (aIIV4). Fluad Quadrivalent is approved for use in persons aged ≥65 years. For the 2020–21 season, both Fluad Quadrivalent and the previously licensed trivalent formulation of Fluad (aIIV3) are expected to be available. Fluad Quadrivalent, like Fluad, contains the adjuvant MF59.

• Anatomic and functional asplenia; active communication between the cerebrospinal fluid (CSF) and oropharynx, nasopharynx, nose, or ear or any other cranial CSF leak; and cochlear implant have been added to the discussion of Contraindications and Precautions for the Use of LAIV4.
  
• Discussion of Use of Influenza Antiviral Medications has been updated to reflect use of LAIV4 in the setting of use of newer influenza antiviral agents.
  
• Recommendations for Persons with a History of Egg Allergy now state that additional measures for those with a history of severe allergic reaction to egg (i.e., vaccination in a medical setting supervised by a health care provider who is able to recognize and manage severe allergic reactions) are needed only if a vaccine other than ccIIV4 or RIV4 is used.
  
• Pregnant women may receive any licensed, recommended, and age-appropriate IIV or RIV4 vaccine. LAIV4 should not be used during pregnancy.
  

Influenza Vaccine Additional Recommendations

Pregnant Women

Your recommendation to pregnant patients makes a difference in protecting expectant mothers and their infants from influenza-related illnesses, hospitalization, and premature labor and delivery. Consider the following points in discussions with expectant mothers:

• The risk of severe illnesses related to the flu is higher in pregnant women than in women who are not pregnant..
• The influenza vaccine is safe for pregnant women in any trimester and has been given to millions of pregnant women in the past decade.
• Live attenuated influenza vaccine (LAIV; FluMist) should not be given during pregnancy.
• It's safe for postpartum women to get the influenza vaccine, even if they are breastfeeding.
• Antivirus drugs are recommended for pregnant women who get the flu, as they can shorten the length of illness by one or two days, and can prevent flu complications, such as pneumonia.

Health Care Personnel

The AAFP supports annual mandatory influenza immunization for health care personnel (HCP), except for refusal due to a documented allergy or medical contraindication. If HCP are not vaccinated, policies to adjust practice activities during flu season are appropriate (e.g., wearing masks, refraining from direct patient care). (AAFP Board of Directors, May 2016)

Patients with Egg Allergy History

As is the case for all vaccines, influenza vaccines contain components that might cause allergic and anaphylactic reactions.Not all such reactions are related to egg proteins; however, the possibility of reactions to influenza vaccines in patients who are egg allergic might be of concern to these patients and vaccine providers.

Currently available influenza vaccines, with the exceptions of recombinant influenza vaccine (RIV4;FluBlok Quadrivalent, licensed for ages 18 and older) and cell-culture-based inactivated influenza vaccine (ccIIV4;Flucelvax Quadrivalent, licensed for ages 4 and older), are prepared by propagation of virus in embryonated eggs and might contain trace amounts of egg proteins, such as ovalbumin.

Severe allergic reactions to vaccines, although rare, can occur at any time, even in the absence of a history of previous allergic reaction. Therefore, all vaccine providers should be familiar with the office emergency plan and be certified in cardiopulmonary resuscitation. For patients who report a history of egg allergy, the CDC's Advisory Committee on Immunization Practices (ACIP) recommends patients with a history of egg allergy who have experienced only urticaria  after exposure to egg should receive influenza vaccine. Any licensed, recommended influenza vaccine (i.e., any IIV, RIV4, or LAIV4) that is otherwise appropriate for the recipient's age and health status may be used.

Patients who report having had reactions to egg involving symptoms other than urticaria (e.g., angioedema or swelling, respiratory distress, lightheadedness, or recurrent vomiting) or who required epinephrine or another emergency medical intervention may similarly receive any licensed, recommended influenza vaccine (i.e., any IIV, RIV4, or LAIV4) that is otherwise appropriate for their age and health status. The selected vaccine should be administered in an inpatient or outpatient medical setting (including, but not necessarily limited to, hospitals, clinics, health departments, and physician offices). Vaccine administration should be supervised by a health care professional who is able to recognize and manage severe allergic reactions.

A previous severe allergic reaction to influenza vaccine, regardless of the component suspected of being responsible for the reaction, is a contraindication to future receipt of the vaccine.

No postvaccination observation period is recommended specifically for patients who are egg allergic. However, the ACIP recommends that vaccine providers consider observing patients (seated or supine) for 15 minutes after administration of any vaccine to decrease the risk for injury should syncope occur.

Patients who are able to eat lightly cooked eggs (e.g., scrambled eggs) without a reaction are unlikely to be allergic. Patients who are egg-allergic might tolerate egg in baked products (e.g., bread or cake). However, tolerance to egg-containing foods does not exclude the possibility of egg allergy. Egg allergy can be confirmed by a consistent medical history of adverse reactions to eggs and egg-containing foods, plus skin or blood testing for immunoglobulin E directed against egg proteins.

Occasional cases of anaphylaxis after administration of influenza vaccines in patients who are have been reported to the Vaccine Adverse Event Reporting System (VAERS). The ACIP will continue to review available data regarding anaphylaxis cases after receipt of influenza vaccines.

Immunization Resources