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Ask the Experts: Influenza

Results (106)

Yes. CDC preferentially recommends Flublok, Fluad, or Fluzone High-Dose for adults age 65 years and older. If none is available, CDC recommends giving any age-appropriate influenza vaccine rather than delaying vaccination. The American Academy of Family Physicians (AAFP) recommends those three products and the mFlusiva mRNA vaccine preferentially for this age group.

Last reviewed: October 11, 2026

Although Fluzone High-Dose (HD-IIV) and Fluad (aIIV) are FDA-licensed for people 65 years and older, in June 2024, ACIP recommended that HD-IIV or aIIV are options for administration to people age 18 through 64 years old who have had a solid organ transplant (SOT) and are on immunosuppressive medication regimens. ACIP expressed no preference for HD-IIV or aIIV over any other age-appropriate IIV or RIV vaccines for SOT recipients.

Last reviewed: October 11, 2026


2:03

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Last reviewed: September 3, 2025

No, and this is not recommended.

Last reviewed: October 11, 2026

People with cancer need protection from influenza. CDC and IDSA recommend an age-appropriate 2026–27 influenza vaccine for immunocompromised adults and children. Inactivated, cell culture-based, recombinant, and mRNA vaccines may be options when age-appropriate; IDSA and CDC recommend against FluMist for immunocompromised people. IDSA notes that data on mRNA influenza vaccine in immunocompromised people are limited at this time. See www.idsociety.org/practice-guideline/Seasonal-RTI-Vaccinations-in-Immunocompromised-Patients/.

Last reviewed: October 11, 2026

AAP provided additional details about timing and product choices for influenza vaccination of immunocompromised children in its 2026 influenza vaccination policy statement (see https://doi.org/10.1542/peds.2026-078778). All immunocompromised children should be vaccinated with an age-appropriate inactivated influenza vaccine (IIV) or recombinant influenza vaccine (RIV), preferably before the start of influenza season. Household contacts also should be vaccinated. The additional considerations from AAP concerning timing and product choice are listed below:

  • For children with malignancy receiving chemotherapy, administer IIV or RIV 2 weeks or more before cytotoxic chemotherapy when possible.
  • For children receiving immunosuppression for underlying autoimmune or autoinflammatory conditions, administer IIV or RIV 2 weeks or more before starting these therapies when possible.
  • For children who will be starting anti-B cell therapies (e.g., rituximab, alemtuzumab), administer IIV or RIV 2 weeks or more before starting these therapies when possible.
  • For children who have received B-lymphocyte–depleting therapies, consider IIV or RIV 3 to 6 months after last dose; earlier vaccination could be considered if influenza is circulating in the community.
  • For children who have received CD19-targeted chimeric antigen receptor T-lymphocyte infusions (CAR-T), consider IIV or RIV 3 to 6 months after CAR-T in patients who are in remission and do not require additional intensive chemotherapy or hematopoietic cell transplant (HCT).
  • For HCT recipients, consider IIV or RIV starting 3 months after HCT.
  • Consider administering 2 doses of high-dose IIV 28 to 42 days apart in pediatric HCT recipients 3 to 17 years of age in the first year after HCT, recognizing that high-dose IIV is not approved for use in children.
  • For solid organ transplant (SOT) recipients 6 months through 17 years of age, consider IIV or RIV at least 1 month after transplantation. For SOT recipients 18 years and older receiving immunosuppressive medications, HD or aIIV are acceptable options.
Last reviewed: October 11, 2026

The Infectious Diseases Society of America (IDSA) published 2026 recommendations for the use of influenza, RSV, and COVID-19 vaccines in people with immunocompromise (see www.idsociety.org/practice-guideline/Seasonal-RTI-Vaccinations-in-Immunocompromised-Patients/). Its timing considerations align with AAP recommendations for timing of influenza vaccination of children with immunocompromise. A table with timing considerations is available at www.idsociety.org/globalassets/idsa/practice-guidelines/vaccine-gl/table-3-2026..pdf

Last reviewed: October 11, 2026

IDSA recommends administering an age-appropriate influenza vaccine at least 3 months after hematopoietic cell transplant (HCT) or CAR-T-cell therapy. IDSA notes that earlier vaccination may be considered during periods of high influenza circulation or before anticipated immunosuppression. See www.idsociety.org/practice-guideline/Seasonal-RTI-Vaccinations-in-Immunocompromised-Patients/.

Last reviewed: October 11, 2026

CDC and the American Academy of Family Physicians (AAFP) recommend annual influenza vaccination for all healthcare personnel. Influenza can be transmitted before symptoms begin, and healthcare personnel may work while infectious, exposing vulnerable patients. See CDC’s 2026 influenza clinical considerations at  www.cdc.gov/flu/hcp/vax-summary/seasonal-influenza-vaccines.html or AAFP’s influenza vaccination recommendations at www.aafp.org/assets/image/upload/v1788277985/pdf_2026_through_2027_influenza_rsv_sars_covid_2_guidance.pdf.

Last reviewed: October 11, 2026


1:18

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Last reviewed: January 9, 2026

CDC and the American Academy of Family Physicians (AAFP) recommend annual influenza vaccination for all healthcare personnel (HCP) who do not have a contraindication. Vaccinating HCP helps protect them and protects patients at increased risk for influenza complications.

Last reviewed: October 11, 2026

CDC and the American Academy of Family Physicians (AAFP) recommend annual influenza vaccination for all healthcare personnel who do not have a contraindication, including paid and unpaid workers who may be exposed to patients or infectious materials.

Last reviewed: October 11, 2026

CDC and the American Academy of Family Physicians (AAFP) recommend annual influenza vaccination for all people working in long-term care facilities who do not have a contraindication.

Last reviewed: October 11, 2026

Since January 2007 the Joint Commission has required accredited organizations to offer annual influenza vaccination to staff, volunteers, and licensed independent practitioners who have close patient contact.

Last reviewed: October 11, 2026

Many healthcare facilities have adopted mandatory vaccination policies for their employees. Immunize.org has included more than 1,200 of these on its Honor Roll for Patient Safety, which gives special recognition to institutions that enforce mandatory vaccination for all personnel who are in the vicinity of a patient (including volunteers and housekeeping staff). To read more about the Honor Roll, or to apply for recognition, go to www.immunize.org/about/excellence/honor-rolls/influenza-vaccination/. In addition, the National Adult and Influenza Immunization Summit (NAIIS) has developed tools to assist post-acute and long-term care facilities that plan to implement influenza vaccination requirements for HCP at www.izsummitpartners.org/naiis-workgroups/influenza-workgroup/tools-for-ltcf/. We hope reviewing these policies and tools will give you the information you need to assist in developing an effective policy for your facility.

Last reviewed: October 11, 2026

Though vaccination is the most effective means of protecting your patients from influenza, there may be instances where employees are not vaccinated for medical or personal reasons. In these instances, some facilities consider reassigning unvaccinated workers to non-patient areas or requiring that they wear masks while working throughout the influenza season.

Last reviewed: October 11, 2026

If a vaccine is covered under the National Childhood Vaccine Injury Act, as influenza vaccine is, it is mandatory under federal law to give the VIS for that vaccine to the vaccinee, regardless of age. Therefore, when you give influenza vaccine to employees and staff, you are required by law to provide them with a VIS.

The inactivated and recombinant influenza vaccine VIS and all available translations of it are here: www.immunize.org/vaccines/vis/influenza-inactivated/. The live attenuated influenza (LAIV) VIS and all available translations of it are here: www.immunize.org/vaccines/vis/influenza-live/.

Immunize.org also offers a printable PDF document with QR codes for easy access to all translations of the inactivated and recombinant influenza vaccine VIS: www.immunize.org/wp-content/uploads/catg.d/p2092.pdf. Healthcare providers or recipients can scan the QR codes to access a digital copy of the English version or one of many translations on their mobile device.

Last reviewed: October 11, 2026

Some studies have shown an increase in healthcare personnel (HCP) influenza vaccine acceptance when decliners are required to sign such a statement. In addition, such statements can help a vaccination program assess the reasons for declination and plan future educational efforts. Immunize.org has posted the following suggested declination form for healthcare workers at www.immunize.org/catg.d/p4068.pdf.

Last reviewed: October 11, 2026

There are many professional associations that have issued policy position statements supporting mandatory healthcare worker influenza vaccination. You can find information about these organizations and their position statements at Immunize.org’s Influenza Vaccination Honor Roll web page: www.immunize.org/about/excellence/honor-rolls/influenza-vaccination/.

Last reviewed: October 11, 2026

Contraindications to egg-based inactivated influenza vaccines (IIV) are a severe allergic reaction to a prior dose of any non-mRNA influenza vaccine (any egg-based IIV, ccIIV, RIV, or LAIV of any valency) or a severe allergy to an influenza vaccine component (except egg). CDC and medical societies recommend that people with egg allergy of any severity (but no history of allergy to the influenza vaccine or an influenza vaccine component) may receive any influenza vaccine appropriate for their age and health status.

Precautions to egg-based IIV include moderate or severe acute illness, and history of Guillain-Barré syndrome within 6 weeks after a dose of influenza vaccine.

Contraindications to cell culture-based IIV (ccIIV) are a history of a severe allergic reaction to a previous dose of ccIIV or any component of ccIIV.

Precautions to ccIIV are moderate or severe acute illness, a history of Guillain-Barré syndrome within 6 weeks after a dose of any non-mRNA influenza vaccine, and a history of a severe allergic reaction to a previous dose of another type of influenza vaccine (e.g., any egg-based IIV, RIV, or LAIV).

Contraindications to RIV are a history of a severe allergic reaction to a previous dose of RIV or any component of RIV.

Precautions to RIV are moderate or severe acute illness, a history of Guillain-Barré syndrome within 6 weeks after a dose of any non-mRNA influenza vaccine, and a history of a severe allergic reaction to a previous dose of another type of influenza vaccine other than an mRNA vaccine (e.g., any egg-based IIV, ccIIV, or LAIV).

The components of mFlusiva mRNA influenza vaccine are different from other influenza vaccines. It contains no influenza antigens. The only contraindication listed on its package insert is a history of severe allergic reaction (e.g., anaphylaxis) to a previous dose of mFlusiva or a component of it (e.g., polyethylene glycol, PEG). The only precaution to its use is a moderate or severe acute illness, with or without fever (defer vaccination until symptoms are resolving). It is not licensed for use during pregnancy because there are insufficient data available on its use during pregnancy.

Last reviewed: October 11, 2026

A severe allergic reaction to an influenza vaccine is a contraindication to receiving another dose of the same vaccine and may be a contraindication or precaution for other influenza vaccine types. The following table summarizes CDC guidance for egg-based IIV and LAIV, cell culture-based IIV, and recombinant vaccine. CDC’s September 2026 interim clinical considerations did not change this guidance. See www.cdc.gov/flu/hcp/vax-summary/seasonal-influenza-vaccines.html.

For mFlusiva, FDA lists a severe allergic reaction to any component as a contraindication. A severe allergic reaction to other non-mRNA influenza vaccines is neither a contraindication nor a precaution to its use. See www.fda.gov/vaccines-blood-biologics/vaccines/mflusiva.

Vaccine (of any valency) associated with previous serious or anaphylactic reaction Available 2026-27 influenza vaccines
Egg-based IIVs
and LAIV		 Cell-culture- based IIV: ccIIV (Flucelvax) Recombinant IIV: RIV (Flublok)
Any egg-based IIV or LAIV Contraindication Precaution † Precaution †
Any ccIIV Contraindication Contraindication Precaution †
Any RIV Contraindication Precaution † Contraindication
Unknown influenza vaccine Allergist consultation recommended

† Note regarding patients having either of the above precautions for either ccIIV or IIV: use of ccIIV and RIV in such instances should occur in an inpatient or outpatient medical setting under the supervision of a healthcare provider (HCP) who can recognize and manage severe allergic reaction; HCPs should consider consulting with an allergist to help identify the vaccine component responsible for the reaction.

Last reviewed: October 11, 2026

Contraindications to LAIV are:

  • a history of severe allergic reaction to a vaccine component (except egg) or after a previous dose of any non-mRNA influenza vaccine (people with egg allergy of any severity may receive LAIV if it is otherwise appropriate for their age and health status)
  • concomitant aspirin- or salicylate-containing therapy in children and adolescents because of the risk of Reye syndrome
  • children age 2 through 4 years who have received a diagnosis of asthma or whose parents or caregivers report that a healthcare provider has told them during the preceding 12 months that their child had wheezing or asthma or whose medical record indicates a wheezing episode during the preceding 12 months
  • immunosuppression due to any cause, including medications, congenital or acquired immunodeficiency states, HIV infection, anatomic asplenia or functional asplenia (e.g., due to sickle cell anemia)
  • cranial cerebral spinal fluid (CSF) leak or cochlear implant (due to potential for CSF leak)
  • close contacts and caregivers of severely immunosuppressed people who require a protected environment
  • pregnancy
  • receipt of influenza antiviral medication within the previous 48 hours (for oseltamivir or zanamivir), previous 5 days (for peramivir), or previous 17 days (for baloxavir)

Precautions are:

  • moderate or severe acute illness with or without fever (defer)
  • history of Guillain-Barré syndrome within 6 weeks after a dose of influenza vaccine
  • asthma in a person age 5 years or older
  • underlying medical conditions that might predispose to complications after influenza virus infection, such as chronic pulmonary, cardiovascular (except isolated hypertension), renal, hepatic, neurologic, hematologic, or metabolic disorders (including diabetes mellitus)
Last reviewed: October 11, 2026

Everyone age 6 months of age or older with egg allergy and no contraindication to vaccination should receive an influenza vaccine. Any influenza vaccine (egg based or non-egg based) appropriate for the person’s age and health status can be used.

Egg allergy alone does not require any additional safety measures for influenza vaccination beyond those recommended for any recipient of any vaccine. As a general principle, all vaccines should be administered in settings in which personnel and equipment needed for rapid recognition and treatment of acute hypersensitivity reactions are available.

For more on the evidence and rationale supporting ACIP’s recommendations regarding influenza vaccination and egg allergy, see pages 12 and 13 of the ACIP recommendations for the 2023–24 season at www.cdc.gov/mmwr/volumes/72/rr/pdfs/rr7202a1-H.pdf.

Last reviewed: October 11, 2026


2:01

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Last reviewed: September 3, 2025

No.

Last reviewed: October 11, 2026

Yes, you can. Some, but not all, studies have reported increased rates of febrile seizures among children, especially those age 12 through 23 months, who received simultaneous vaccination with IIV and pneumococcal conjugate vaccine (PCV13, Pfizer) or DTaP vaccine (Daptacel, Infanrix, Pediarix, Pentacel), when compared with children who received these vaccines separately. However, because of the risks associated with delaying either of these vaccines, ACIP does not recommend administering them at separate visits or deviating from the recommended vaccine schedule in any way. The risk of febrile seizure following coadministration of influenza vaccine with currently recommended PCV15 or PCV20 vaccines has not been evaluated.

Febrile seizures may be triggered by any cause of fever and occur in up to 5% of all children They are generally benign. Healthcare providers should be prepared to answer parents’ questions about febrile seizures and fever when discussing vaccinations. Here is a CDC resource that addresses these concerns: www.cdc.gov/vaccine-safety/about/febrile-seizures.html.

Last reviewed: October 11, 2026

The probability of a serious allergic reaction following any vaccine is extremely low if the person is properly screened. ACIP has not issued a recommendation that desensitization injections and vaccines be separated by any specific time period; consequently, we feel that you should take the opportunity to vaccinate.

Last reviewed: October 11, 2026

Yes. A history of GBS unrelated to influenza vaccine is not a contraindication or precaution to influenza vaccination. GBS within 6 weeks following a previous dose of influenza vaccine is considered a precaution for use of influenza vaccines.

Last reviewed: October 11, 2026

The current CDC VIS for inactivated and recombinant influenza vaccine and the current CDC VIS for live attenuated influenza vaccine are both dated January 31, 2025. The IIV and RIV VIS and translations are at www.immunize.org/vaccines/vis/influenza-inactivated/. The LAIV VIS and translations are at www.immunize.org/vaccines/vis/influenza-live/. FDA provides separate Information for Recipients and Caregivers for mFlusiva at www.fda.gov/vaccines-blood-biologics/vaccines/mflusiva. There is not a VIS for mFlusiva at this time.

Last reviewed: October 11, 2026

CDC discourages the practice of prefilling vaccine into syringes for several reasons, including:

  • The increased possibility of administration and dosing errors
  • The increased risk of inappropriate storage temperature
  • The probability of bacterial contamination
  • The probability of reducing the vaccine’s potency over time

Prefilling vaccine into syringes also violates basic medication administration guidelines, which state that an individual should administer only those medications he or she has prepared and drawn up.

Although pre-drawing vaccine is discouraged, a limited amount of vaccine may be pre-drawn in a mass vaccination clinic setting under the following conditions:

  • Only a single type of vaccine (for example, influenza) is administered at the mass vaccination clinic setting
  • Vaccine is not drawn up in advance of its arrival at the mass vaccination clinic site
  • These pre-drawn syringes are stored at temperatures appropriate for the vaccine
  • No more than 1 vial or 10 doses (whichever is greater) is drawn into syringes
  • Clinic staff monitor patient flow carefully and avoid drawing up unnecessary doses or delaying administration of pre-drawn doses

At the end of the clinic day, all remaining vaccine in syringes prefilled by staff should be discarded.

Vaccination clinic staff seeking to increase their speed and efficiency may consider using formulations packaged in manufacturer-filled syringes (MFS).

Last reviewed: October 11, 2026

Vaccinating people against influenza who have recently tested positive for COVID-19 involves multiple considerations, such as whether vaccinating them could expose others to COVID-19, how sick they are, their risk for severe influenza illness, the ability to vaccinate at a later date, and the desire to avoid confusing postvaccination symptoms with those of COVID-19. Usually, people who are known to be infectious should not be brought to a vaccination setting if doing so could expose others to COVID-19. Any moderate or severe acute illness is a precaution to influenza vaccination: vaccination should generally be deferred until recovery. For people with mild or asymptomatic COVID-19, delaying vaccination also might be considered to avoid confusing COVID-19 symptoms with postvaccination reactions.

Last reviewed: October 18, 2026

Inactivated and recombinant influenza vaccines are not known to cause false positive nasal swab tests. The results may indicate real infections; however, false positive test results are possible with rapid tests, and these are more likely to occur if the tests are done when influenza prevalence in the area is low, such as early in the influenza season. For more information regarding interpretation of rapid influenza tests see www.cdc.gov/flu/professionals/diagnosis/rapidlab.htm.

Last reviewed: October 11, 2026

Injectable influenza vaccines should be administered intramuscularly. IIV should be administered in the anterolateral thigh muscle of an infant or young child. IIV, RIV, and mFlusiva should be administered in the deltoid muscle of an older child, adolescent, or adult; the anterolateral thigh may be used if necessary. Immunize.org’s administration guide is available at www.immunize.org/catg.d/p2020.pdf.

Last reviewed: October 11, 2026

This is not an acceptable practice. Doses of influenza vaccine (or any other vaccine) should never be split into “half doses.” If a “half dose” is administered, it should not be accepted as a valid dose. The second half of the dose may be administered if the error is caught and corrected on the same day; if not, repeat the vaccination on a different day as soon as possible with a full age-appropriate dose.

Last reviewed: October 11, 2026

Yes. Syncope may occur following any vaccination. It is prudent for all people to be observed for syncope for at least 15 minutes after any vaccination. Immunize.org has a 1-page resource for healthcare professionals that summarizes ways to reduce the risk of post-vaccination syncope: www.immunize.org/wp-content/uploads/catg.d/p4260.pdf.

Last reviewed: October 11, 2026

Low-dead-space syringes can reduce vaccine wastage. In 2026–27 only a small quantity of Fluzone (Sanofi) is available in a 5.0 mL multidose vial. Follow the manufacturer’s package insert for the number of doses that may be withdrawn.

Last reviewed: October 11, 2026

No. Only the number of doses indicated in the manufacturer’s package insert should be withdrawn. For a 5.0 mL multidose vial of Fluzone, this is 10 doses. After the maximum number of doses has been withdrawn, discard the vial even if vaccine remains and the expiration date has not been reached.

Last reviewed: October 11, 2026

RIV is not licensed for people younger than 9 years of age, so there are no data regarding safety and efficacy in this age group. However, no serious side effects would be expected. The dose does not need to be repeated and should be considered valid. Even if no adverse reaction occurs, vaccine administration errors like this should be reported to the Vaccine Adverse Events Reporting System (VAERS) at www.vaers.hhs.gov.

Last reviewed: October 11, 2026

If the error is discovered on the same clinic day, administer the remaining 0.25 mL of FluLaval that day. If it cannot be corrected that day, do not count the partial dose. Recall the child as soon as possible and administer a full age-appropriate dose of FluLaval, Fluarix, Fluzone, or Flucelvax.

Last reviewed: October 11, 2026

All 2026–27 influenza vaccines, including inactivated, recombinant, live attenuated, and mRNA vaccines, should be stored refrigerated at 2° through 8°C (36° through 46°F). Do not freeze influenza vaccine, and do not use vaccine that has been frozen. Follow each manufacturer’s package insert for product-specific handling and storage information.

Last reviewed: October 11, 2026

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