MVEC’s influenza vaccine FAQ’s provide answers to commonly asked questions on the use of the influenza vaccine in 2021. It has been designed to be used in conjunction with MVEC’s influenza vaccine recommendations.

General influenza vaccine questions

  • When is the ideal time to be immunised against the flu?

    Annual vaccination before the onset of influenza season is recommended. The peak period of circulating influenza disease is typically June to September, however out of season cases do occur. Optimal protection against influenza occurs within the first 3-4 months following vaccination. It is never too late in the season to vaccinate.

  • Should we have a dose of the vaccine early in the season and a second dose later in the season?

    For healthy individuals, the recommendation is to receive one dose of influenza vaccine annually. Re-vaccination later in the same year is not routinely recommended but may benefit some individuals due to circumstances such as travel or pregnancy. The decision to recommend a second dose should take into account a person’s medical risk factors, risk of disease exposure and the current circulating virus strains.

  • Why do I need an influenza vaccine every year?

    The circulating strains of influenza virus varies each year and therefore influenza vaccines are modified annually to provide protection against those more commonly circulating strains. Optimal influenza disease protection occurs in the first 3-4 months following immunisation before it begins to wane. Annual influenza immunisation is therefore strongly recommended to have the best possible protection against influenza disease and its complications.

  • I am a healthy person, do I need a flu vaccine?

    Influenza can be a very serious disease resulting in hospitalisation and death. Even in cases where disease and its complications are not severe, it can cause a great inconvenience for the individual, including the cost of GP visits and medications, as well as time off work for themselves or to care for their sick child.

    In some cases, a person may not get severe disease however infection can be spread to other people. This can be significant when it is spread to those who are too young to be immunised or are at higher risk of complications of disease.

  • How quickly will I develop immunity after receiving the influenza vaccine?

    Most people will develop immunity within two to three weeks of vaccination providing optimal protection for the first 3-4 months thereafter. As influenza disease usually occurs from June, with the peak around August, vaccinating from mid-April will allow people to develop immunity before influenza transmission is at its peak. You can also speak with your doctor for advice on the best time to receive your vaccine, based on your individual circumstances.

  • I have already had confirmed influenza disease this year. Do I still need the influenza vaccine and when should I have it?

    The influenza vaccine would still be recommended for someone with a history of confirmed influenza infection as the vaccine protects against multiple strains of influenza disease. The influenza vaccine can be administered as soon as the patient has recovered from their illness.

  • What is the difference between egg-based and cell-based influenza vaccines?

    Traditional influenza vaccines are made by cultivating influenza viruses in chicken eggs. Cell-based influenza vaccines are made by growing influenza viruses in animal cells lines (canine kidney). By using a cell-based platform, influenza vaccines have the potential to provide protection against influenza strains that are more closely matched to the circulating influenza strains in the community.

    Cell-based influenza vaccines have been used internationally since 2012 and in 2021 a cell-based influenza has been registered for use within Australia for the first time. Flucelvax quad® is available for private purchase for immunisation of those aged ≥ 9 years.

    Expected side effects from cell-based influenza vaccines are consistent to the side effects expected from traditional egg-based influenza vaccines. The most commonly reported symptoms are local injection site reactions, including pain and redness.

  • Why are the strains included in the egg-based influenza vaccines different to the strains included in the cell-based influenza vaccines?

    The method of manufacture differs for egg-based influenza vaccines and cell-based influenza vaccines. This can impact the ability to produce the same strains of virus for both platforms. In cases where it is not possible to produce the same strains, strains with similar properties are selected.

    The recommendation for which strains should be included in influenza vaccines is made by the World Health Organization’s Global Influenza Surveillance and Response System (GISRS) based on epidemiological data, genetic characteristics of the virus, antiviral resistance, vaccine effectiveness and the availability of candidate vaccine viruses.

Administration of influenza vaccines

  • Can I give my patient < 65 years of age the adjuvanted influenza vaccine Fluad® Quad to produce a greater immune response?

    No. Adjuvanted formulations are currently only registered for use in those ≥ 65 years of age. They are designed to illicit a better immune response in the older population where response to the standard QIV formulations have been found to be less effective. Standard QIV formulations are recommended for those aged < 65 years.

  • When is it too late in the season to get the influenza vaccine?

    It is never too late in the season to be immunised as disease can circulate all year round. Immunisation should still be offered while vaccine expiry date remains valid. Some brands have an expiry date of February the following year.

  • Can the influenza vaccine be given at the same time as other vaccines?

    With the exception of COVID-19 vaccines (see below question), people can safely receive inactivated influenza vaccines at the same time as other vaccines. This includes pneumococcal, meningococcal and live vaccines, as well as concurrently administering a Boostrix® vaccine (diphtheria-tetanus-pertussis) to pregnant women.

  • What is the process when a patient requires both influenza and COVID-19 vaccines?

    The preferred minimum interval for administration of influenza vaccines and COVID-19 vaccines is 7 days. A shorter interval (including co-administration on the same day) is acceptable in situations where there is an increased risk of disease (such as in a COVID-19 outbreak) or where there are logistical issues (such as difficulty in ability to maintain the minimum interval). A shortened time frame may result in a higher frequency of mild to moderate side effects. Where the minimum interval of 7 days has not been maintained, revaccination with either vaccine is norecommended or required.

  • What is the advice if influenza vaccines and COVID-19 vaccines are inadvertently co-administered on the same day, or administered with a shorter interval than the preferred 7 days?

    If influenza and COVID-19 vaccines are administered on the same day or are administered within a shorter timeframe than 7 days, revaccination with either vaccine is not recommended or required. The vaccinee should be advised of the possibility for a higher incidence of mild to moderate side effects following vaccination.

  • Can influenza vaccines be given to someone who has had Guillain-Barre Syndrome (GBS)?

    Influenza vaccination has been identified as a possible cause of GBS following H1N1 containing vaccines, but the evidence is variable and at a very low rate, lower than the rate of GBS caused by ‘wild type’ influenza. As per the AusVaxSafety clinical resources flow chart [see resources], influenza immunisation is generally not recommended for people with a history of GBS occurring within 6 weeks of receiving a previous influenza vaccine. However specialist immunisation advice should be sought to discuss the potential benefit of vaccination and the risk for GBS recurrence post vaccination or GBS recurrence post influenza disease. There are no concerns administering influenza vaccines to patients who have a history of developing GBS more than 6 weeks following an influenza vaccine.

  • In children (< 9 years) who received the influenza vaccine for the first time last year but only received 1 dose, how many doses are required this year?

    Only 1 dose is required in this instance. 2 doses of the influenza vaccine are recommended for children < 9 years of age in the first year of receiving the vaccine, however if the second dose was inadvertently missed, it does not require catch up and only 1 dose is required in future years.

  • Children (< 9 years) need 2 doses of the influenza vaccine in their first year of being immunised. Do they need to receive the same brand for both doses?

    Influenza vaccine brands are interchangeable. Always ensure that the age-appropriate brands are administered.

  • What is the recommended site for injection when giving multiple vaccines in the same visit?

    The preferred injection site for adults and children ≥ 12 months of age is the deltoid. For infants < 12 months of age the recommended injection site is the middle third of the vastus lateralis (anterolateral thigh). More than 1 vaccine can be given into each site for injection ensuring a 2.5cm spacing between each vaccine. In some circumstances in children ≥ 12 months of age, the anterolateral aspect of the thigh may also be considered as an alternate site if required. For more information please refer to MVEC: Administration of injected vaccines-correct technique.

Safety of influenza vaccines

  • How do I know that influenza immunisation is safe in children?

    Surveillance of influenza vaccine safety continues to occur via AusVaxSafety which monitors post influenza immunisation outcomes. In children 6 months to < 5 years of age, it has been found that children in this age group experience only low rates of fevers (2%) and medical attendance (1%) post influenza immunisation. SAEFVIC (Surveillance of Adverse Events Following Vaccination In the Community) would be happy to discuss any vaccine safety queries and online reporting of AEFI via the website is encouraged [www.saefvic.org.au].

  • What are the expected side effects of the flu vaccine?

    Common side effects following the influenza vaccination include pain, redness and swelling at the injection site as well as fever, malaise and myalgia. Symptoms usually occur within the first 24-48 hours. Cell-based influenza vaccines have a similar side-effects profile as traditional egg-based influenza vaccines. Following immunisation with adjuvanted quadrivalent formulations, side effects may occur slightly more commonly than with standard QIV formulations.

  • Is it safe to receive the influenza vaccine during pregnancy?

    It is safe and recommended to receive the influenza vaccine during pregnancy. Immunisation not only provides protection for the mother against disease, but maternal antibodies are also transmitted to the baby, which will provide protection against disease for the first few months of life. Influenza immunisation is funded on the National Immunisation Program (NIP) for all pregnant women.

  • Is it safe to receive the influenza vaccine whilst breastfeeding?

    Annual influenza immunisation is safe and recommended for breastfeeding mothers. Babies less than 6 months of age are at greatest risk from disease yet cannot receive influenza vaccines until they are 6 months of age. Maternal immunisation will provide protection for mothers as well as providing some passive protection for babies through the secretion of antibodies until they are old enough to receive their own influenza vaccine.

  • Cell-based influenza vaccines are available in Australia for the first time this year. How do I know they are safe?

    All vaccines must pass through strict safety and efficacy criteria before the Therapeutic Goods Administration (TGA) will grant approval for use within Australia. To read more about the vaccine development process please refer to MVEC: Development of vaccines.

    Cell-based influenza vaccines have been used internationally since 2012. Expected side effects from cell-based influenza vaccines are consistent to the side effects expected from traditional egg-based influenza vaccines. The most commonly reported symptoms are local injection site reactions, including pain and redness.

Pregnancy, breastfeeding and influenza vaccines

  • My pregnant patient received last year’s influenza vaccine when in early pregnancy in 2020, should they also receive a dose of 2021 influenza vaccine now during the same pregnancy?

    Yes, women who received the previous year’s seasonal influenza vaccine early in their pregnancy are also recommended to receive the current year’s seasonal influenza vaccine to ensure protection against the current circulating strains.

  • When is the ideal time to receive a flu vaccine in pregnancy?

    Pregnant women can receive influenza vaccine during any stage of pregnancy. Timing is often dependent on seasonality and availability of the vaccine.

  • Is it safe to receive the influenza vaccine during pregnancy?

    It is safe and recommended to receive the influenza vaccine during pregnancy. Immunisation not only provides protection for the mother against disease, but maternal antibodies are also transmitted to the baby, which will provide protection against disease for the first few months of life. Influenza immunisation is funded on the National Immunisation Program (NIP) for all pregnant women.

  • Is it safe to receive the influenza vaccine whilst breastfeeding?

    Annual influenza immunisation is safe and recommended for breastfeeding mothers. Babies less than 6 months of age are at greatest risk from disease yet cannot receive influenza vaccines until they are 6 months of age. Maternal immunisation will provide protection for mothers as well as providing some passive protection for babies through the secretion of antibodies until they are old enough to receive their own influenza vaccine.

  • Why is influenza vaccination recommended in pregnancy?

    Pregnant women are at greater risk of morbidity and mortality from influenza disease than non-pregnant women. They are more than twice as likely to be hospitalised with influenza disease as other people with influenza. Babies less than 6 months of age are at greatest risk of disease and death from influenza. Vaccinating pregnant women will also provide protection to babies for the first few months of life until they can be immunised against influenza from 6 months of age.

Adjuvanted QIV (Fluad® Quad) influenza vaccines

  • Why are adjuvanted formulations of influenza vaccine the preferred vaccine for those ≥ 65 years?

    A gradual decline of the immune system occurs as people age (known as immunosenescence), impacting how the immune system responds to immunisation. For adults aged ≥ 65 years the adjuvanted QIV, Fluad® Quad is preferentially recommended over standard QIVs as the antibody response is increased in comparison to non-adjuvanted QIV influenza vaccines.

  • If a standard QIV formulation has been given to my patient aged ≥ 65 years, do I need to re-vaccinate with the recommended adjuvanted vaccine (Fluad® Quad)?

    If a patient aged ≥ 65 years old has already received a dose of a 2021 standard QIV vaccine they do not need re-vaccination or booster dosing with Fluad® Quad.

Special risk patients

  • Do immunosuppressed people require 2 doses of influenza vaccines?

    People with certain immunocompromising conditions (ie: solid organ transplant, stem cell transplant etc) should receive 2 doses, a minimum of 4 weeks apart, of QIV formulation of influenza vaccine in the first year of being immunosuppressed. Only 1 dose is required annually thereafter. An exception to this is in patients ≥ 65 years, as they are recommended to only receive 1 dose of the higher-immunogenicity QIV (refer to immunisation specialist for individual advice in this patient group).

  • Should my ≥ 65 year old immunosuppressed patient receive 2 doses of adjuvanted QIV this year?

    Only 1 dose of Fluad® Quad vaccine is recommended per year, regardless of medical conditions.

Vaccine components

  • My patient is allergic to egg, how can they receive a flu vaccine safely?

    Based on prospective and retrospective studies of influenza vaccination in those with and without egg allergy (including egg anaphylaxis), the presence of egg allergy does not increase the risk of allergic reactions to the influenza vaccine. Egg-based influenza vaccines can be administered in community vaccination clinics (which may or may not have direct medical practitioner supervision), General Practitioner surgeries or immunisation clinics, as a single dose followed by the recommended 15 minute observation period. It is not necessary to preferentially administer cell-based influenza vaccines in this patient group. For further information refer to MVEC: Allergy and immunisation.

  • Can patients with latex allergies receive the influenza vaccine?

    All influenza vaccines available under the NIP in 2021 are latex free. People with a latex allergy can safely be vaccinated with influenza vaccines that are available under the NIP.

  • What are cell-based influenza vaccines?

    Cell-based influenza vaccines are made by growing influenza viruses in animal cell lines (canine kidney). This is a different method of manufacture compared with traditional influenza vaccines which are created by cultivating influenza viruses in chicken eggs.

Authors: Georgina Lewis (Clinical Manager, SAEFVIC, Murdoch Children’s Research Institute), Rachael McGuire (SAEFVIC Research Nurse, Murdoch Children’s Research Institute) and Daryl Cheng (Senior Research Fellow, Murdoch Children’s Research Institute)

Reviewed by: Rachael McGuire (MVEC Education Nurse Coordinator)

Date: June 2021

Materials in this section are updated as new information and vaccines become available. The Melbourne Vaccine Education Centre (MVEC) staff regularly reviews materials for accuracy.

You should not consider the information in this site to be specific, professional medical advice for your personal health or for your family’s personal health. For medical concerns, including decisions about vaccinations, medications and other treatments, you should always consult a healthcare professional.