Seasonal Influenza Prevention & Control

Influenza Vaccine Updates

For the 2021-2022 season, there is no preferential recommendation for any one flu vaccine over another. 

1. All seasonal influenza vaccines expected to be available for the 2021-22 season are quadrivalent, containing one influenza A(H1N1)pdm09 virus, one influenza A(H3N2) virus, one influenza B/Victoria lineage virus, and one influenza B/Yamagata lineage virus.
2. The composition of the 2021–22 U.S. seasonal influenza vaccines includes updates to the influenza A(H1N1)pdm09 and influenza A(H3N2) components. For the 2021–22 season, U.S.-licensed influenza vaccines will contain an influenza A/Victoria/2570/2019 (H1N1)pdm09-like virus (for egg-based vaccines) or an influenza A/Wisconsin/588/2019 (H1N1)pdm09-like virus (for cell-based and recombinant vaccines); an influenza A/Cambodia/e0826360/2020 (H3N2)-like virus; an influenza B/Washington/02/2019 (Victoria lineage)-like virus; and an influenza B/Phuket/3073/2013 (Yamagata lineage)-like virus.
3. One licensure change is described. On March 3, 2021, FDA granted approval for the use of Flucelvax Quadrivalent (cell culture-based quadrivalent inactivated influenza vaccine, ccIIV4), for children aged 2 through <4 years.  Flucelvax Quadrivalent had previously been approved for persons aged ≥4 years; approval for those aged 4 through <18 years was based on immunogenicity data and required a post-marketing efficacy study.  The new approval is based upon a randomized blinded clinical efficacy study conducted among children 2 through <18 years over two seasons, in which Flucelvax Quadrivalent demonstrated efficacy against laboratory-confirmed influenza of 54.6% (95%CI  7%-62.1%) compared with a non-influenza control vaccine.  Flucelvax Quadrivalent is now approved for persons aged ≥2 years.
4. Guidance concerning the timing of vaccination has been updated to reflect consideration of COVID-19 vaccination, which is expected to continue in the United States prior to and during the 2021-22 influenza season. Current guidance for the use of COVID-19 vaccines indicates that these vaccines may be given concomitantly with other vaccines, including influenza vaccines.  Providers should consult current COVID-19 vaccine recommendations and guidance for up to date information.  CDC/ACIP recommendations for the use of COVID-19 vaccines can be found at https://www.cdc.gov/vaccines/hcp/acip-recs/vacc-specific/covid-19.html.  Interim clinical guidance for the use of COVID-19 vaccines can be found at https://www.cdc.gov/vaccines/covid-19/info-by-product/clinical-considerations.html.  These pages should be checked periodically for updated information.[MB1] 
5. Guidance concerning timing of vaccination has been modified to indicate that vaccination soon after vaccine becomes available can be considered for persons in the third trimester of pregnancy. As in previous seasons, children who need two doses of influenza vaccine administered at least four weeks apart are recommended to receive the first dose soon after vaccine becomes available. For non-pregnant adults, early vaccination (i.e., in July and August) might be associated with suboptimal immunity before the end of the influenza season, particularly for older adults.  
6. Guidance concerning contraindications and precautions to the use of ccIIV4 and RIV4 were updated. For each of these vaccines, a severe allergic reaction to a previous dose of that vaccine or its components is a contraindication, while a severe allergic reaction to a previous dose of any other influenza vaccine is a precaution.  If ccIIV4 or RIV4 is administered to such individuals, vaccination should occur in an inpatient or outpatient medical setting and be supervised by a health care provider who is able to manage severe allergic reactions.

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