As an additional service to IZ Express readers, we periodically publish special editions such as this one, providing you with new and updated Ask the Experts questions and answers from Immunize.org experts. This issue includes 13 Q&As about influenza vaccination based on recently updated ACIP recommendations.
To find the full set of Immunize.org's Ask the Experts influenza vaccination Q&As, visit www.immunize.org/askexperts/experts_inf.asp.
You can find all of these questions and answers, plus more than 1,200 others about vaccines and vaccine administration, on our "Ask the Experts" gateway page at www.immunize.org/askexperts.
Immunize.org’s team of experts includes Kelly L. Moore, MD, MPH (team lead), Carolyn B. Bridges, MD, FACP, and Iyabode Beysolow, MD, MPH.
Influenza Vaccination Questions
Q: Please summarize what’s new in the 2022–23 influenza vaccine recommendations?
A: Yearly influenza vaccination continues to be recommended for everyone age 6 months and older. All available influenza vaccines in the United States continue to be quadrivalent (containing two influenza A and two influenza B strains). The changes in the CDC’s published Advisory Committee on Immunization Practices (ACIP) recommendations for influenza vaccination in 2022–2023 are summarized below:
- The 2022–23 vaccines include new influenza A (H3N2) and influenza B/Victoria lineage virus vaccine antigens.
- Flucelvax Quadrivalent (ccIIV4, Seqirus) is now FDA-approved for children age 6 months and older.
- Adults age 65 years and older should preferentially receive one of three higher dose or adjuvanted influenza vaccines: Fluzone High-Dose Quadrivalent (HD-IIV4, Sanofi), Flublok Quadrivalent recombinant (RIV4, Sanofi), and Fluad Quadrivalent adjuvanted (aIIV4, Seqirus) influenza vaccines. If none of these three preferred vaccines are available, any age-appropriate flu vaccine may be used.
- Updates were made to the recommended timing of vaccination. Influenza vaccination of most adults in July and August should be avoided unless there is a concern that later vaccination may not be possible. Vaccination in July and August may be considered for people in their third trimester of pregnancy. Children who need one or two doses can get vaccinated in July and August. Vaccination of everyone age 6 months and older should continue as long as influenza viruses are circulating, and unexpired vaccine is available.
The current ACIP recommendations for influenza vaccination are available here: www.cdc.gov/mmwr/volumes/71/rr/pdfs/rr7101a1-H.pdf.
Q: How serious a problem is influenza in the United States?
A: Influenza is the second most frequent cause of death from a vaccine-preventable disease in the United States after COVID-19. Rates of infection from seasonal influenza are highest among children, but the risks for complications, hospitalizations, and deaths are higher among adults age 65 years and older, children younger than 5 years, pregnant individuals, and people of any age who have medical conditions that place them at increased risk for complications from influenza.
From the 2010–11 through the 2019–20 seasons, the annual influenza-related disease burden has varied from approximately 9 to 45 million illnesses, 4 to 21 million medical visits, 140,000 to 810,000 hospitalizations and 12,000 to 61,000 deaths per year, including an average of 133 pediatric deaths reported to CDC (range 37–199) each year. For the 2020–21 and 2021–22 seasons, influenza disease burden was likely substantially reduced as a result of measures taken by many people to reduce the transmission of COVID-19, such as wearing face masks in public and reducing social interactions. Preliminary CDC estimates of the influenza burden during the 2021–22 season are: 8–11 million illnesses, 3.7–6.1 million medical visits, 82,000–170,000 hospitalizations, and 5,000–14,000 deaths. For more information on the health burden of influenza, see www.cdc.gov/flu/about/burden/index.html.
Q: Since influenza virus circulation has been quite low since the fall of 2020, what might be expected for 2022–23 influenza season?
A: The timing and severity of influenza seasons are always unpredictable. Influenza viruses circulated at very low levels while measures to prevent the spread of COVID-19 were widely adopted, including social distancing, mask wearing, and reduction in travel. As the use of these COVID-19 mitigation measures has decreased, there has been an increase in the circulation of influenza and other respiratory viruses. Current information on influenza virus circulation can be found at www.cdc.gov/flu/weekly/index.htm.
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Q: Which influenza vaccines will be available during the 2022–23 influenza season?
A: Multiple manufacturers are producing quadrivalent influenza vaccine for the U.S. market for the 2022–23 season. Inactivated influenza vaccines (IIV4) will be produced using egg-based, cell culture-based, and recombinant technologies. Live attenuated nasal spray vaccine will also be available.
Influenza vaccines are not all licensed for the same age groups.
Immunize.org has a 1-page printable document that summarizes each of the products available for the current influenza vaccination season at www.immunize.org/catg.d/p4072.pdf.
Q: Is it true that ACIP and CDC now recommend certain influenza vaccines over others for people age 65 years and older?
A: Aging decreases the body's ability to develop a good immune response after getting influenza vaccine, which places older people at greater risk of severe illness from influenza.
After years of review and deliberation, ACIP voted in June 2022 to recommend that all adults age 65 and older should preferentially receive one of the three different vaccine products that evidence suggests are likely to perform better than standard dose, unadjuvanted vaccines: Flublok recombinant quadrivalent influenza vaccine (RIV4, Sanofi), Fluad quadrivalent adjuvanted vaccine (aIIV4, Seqirus), and Fluzone High-Dose quadrivalent vaccine (HD-IIV, Sanofi). However, if none of these three vaccines is available at the time of vaccination, any age-appropriate influenza vaccine may be administered.
For a thorough review of the evidence for this recommendation, see the current published ACIP recommendations for influenza vaccination: www.cdc.gov/mmwr/volumes/71/rr/pdfs/rr7101a1-H.pdf.
Q: When does CDC recommend starting influenza vaccination?
A: For most people, vaccination should begin in September and, ideally, be done by the end of October. For people not vaccinated by the end of October, vaccination efforts should continue as long as influenza viruses are circulating and unexpired vaccine is available.
For most adults, vaccination in July and August should be avoided unless there is concern that vaccination later in the season might not be possible. Early vaccination has been associated with decreased vaccine effectiveness before the end of the influenza season, particularly among older adults.
Vaccination in July and August may be considered for people in their third trimester of pregnancy, to allow time for protective maternal antibodies to transfer to the fetus, providing protection during early infancy. Children younger than 9 years old who need two doses of vaccine this season should receive their first dose as soon as possible so that they can get their second dose before the end of October. Children who need only one dose also can be vaccinated in July or August.
Q: May influenza vaccines be given at the same time as other vaccines, including COVID-19 vaccines?
A: Yes. CDC’s clinical guidance for the use of COVID-19 vaccines states that any vaccine may be given on the same day or any day before or after COVID-19 vaccination, at a different anatomic site. According to the CDC’s “General Best Practice Guidelines for Immunization,” simultaneously administering all vaccines for which a person is eligible at the time of a visit increases the probability that a person will be fully vaccinated by the appropriate time.
IIV4 and RIV4 can be administered without regard to the timing of other live or inactivated vaccines. Injectable vaccines should be administered in separate anatomic sites when given on the same day.
LAIV4 may be given on the same day as any other live or inactivated vaccines. However, if two live vaccines are not given on the same day, they should be separated by at least 4 weeks.
Q: Can people who are currently infected with COVID-19 be vaccinated against influenza?
A: 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 in isolation 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 might be considered to avoid confusing COVID-19 symptoms with postvaccination reactions.
CDC may continue to modify recommendations for vaccination of this population.
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Q: Which children younger than age 9 years will need 2 doses of influenza vaccine in this influenza season?
A: Children age 6 months through 8 years should receive a second dose 4 weeks or more after the first dose 1) if they are receiving influenza vaccine for the first time, 2) if they have not received a total of at least two doses of any seasonal influenza vaccine before July 1 of the current year, or 3) if their vaccination history is unknown. The two previous doses need not have been received during the same season or consecutive seasons.
Children who are 8 years old and are recommended to receive two doses during the current season but who have a 9th birthday during the current season before receiving dose 2 should still receive dose 2.
Immunize.org's handout titled "Guide for Determining the Number of Doses of Influenza Vaccine to Give to Children Age 6 Months Through 8 Years" provides additional guidance on this issue; it is available at www.immunize.org/catg.d/p3093.pdf.
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Q: Can a child age 6 months through 8 years who needs 2 doses of influenza vaccine this season receive different products for the two doses or do they have to be the same?
A: The two doses may be the same or different products.
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Q: Which healthcare personnel should be vaccinated against influenza?
A: It is important to vaccinate all healthcare personnel, including paid and unpaid workers who may be exposed to patients or infectious materials. This includes direct patient care staff (e.g., physicians, nurses, and therapists), and staff and volunteers in pharmacy, radiology, laboratory, human resources, facilities management (housekeeping), food services, and laundry. Vaccination should include healthcare staff in all settings, such as hospitals, outpatient clinics, pharmacies, emergency response, nursing homes and assisted living facilities, and home care.
Q: What is the latest ACIP guidance on influenza vaccination and egg allergy?
A: ACIP recommends that people with a history of egg allergy who have experienced only hives after exposure to egg should receive influenza vaccine without specific precautions (except the standard 15-minute observation period for syncope). Any age-appropriate vaccine may be used.
People who report having had a reaction to eggs involving symptoms other than urticaria (hives) (e.g., angioedema or swelling, respiratory distress, lightheadedness, or recurrent vomiting) or who required epinephrine or other emergency medical attention can also receive any age-appropriate influenza vaccine. If a vaccine other than Flucelvax Quadrivalent (ccIIV, Seqirus) or Flublok Quadrivalent (RIV4, Sanofi) is given, the vaccine should be administered in an inpatient or outpatient medical setting. Vaccine administration should be supervised by a healthcare provider who is able to recognize and manage severe allergic conditions.
Although not specifically recommended by ACIP, providers may prefer administering an age-appropriate egg-free vaccine (ccIIV4 or RIV4) to patients with severe egg allergy.
A previous severe allergic reaction to influenza vaccine, regardless of the component suspected to be responsible for the reaction, is a contraindication to future receipt of the vaccine. For a complete list of vaccine components (i.e., excipients and culture media) used in the production of the vaccine, check the package insert (available at www.immunize.org/fda) or go to www.cdc.gov/vaccines/pubs/pinkbook/downloads/appendices/B/excipient-table-2.pdf.
For more details about giving influenza vaccine to people with a history of egg allergy, see the ACIP guidance at www.cdc.gov/mmwr/volumes/69/rr/pdfs/rr6908a1-H.pdf. You may also find the Immunize.org handout "Influenza Vaccination of People with a History of Egg Allergy" helpful (see www.immunize.org/catg.d/p3094.pdf).
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Q: What is the most up-to-date Influenza Vaccine Information Statement (VIS) for the 2022–23 influenza season?
A: Both the inactivated and recombinant influenza vaccine VIS and the live influenza vaccine VIS were updated on August 6, 2021. These VISs and translations in multiple languages are available here: www.immunize.org/vis/.
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