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Optimize your protection against the flu and COVID-19

Published November 7th, 2022

Over the course of the coronavirus pandemic, flu activity and severity has been lower than usual due to mitigation measures in place against COVID-19. However, the Southern Hemisphere’s flu season foreshadows a possible surge in flu activity in the United States this winter1,2. PHM strongly recommends that you receive the flu vaccine this year to optimize your protection against the flu and potential serious complications3. Of note and in agreement with the Centers for Disease Control and Prevention (CDC) and the Advisory Committee on Immunization Practices (ACIP), we recommend the use of higher dose flu vaccines, such as Fluzone High Dose Quadrivalent or Flublok Quadrivalent Flu Vaccine, in adults aged 65 years or older.

Additionally, amidst the possible surge in flu activity, there is continued concern for COVID-19 with the emergence of new Omicron variants. It is particularly important to protect yourself and the people around you from both the flu and COVID-19 this season while the viruses circulate simultaneously.

Are flu vaccines even effective?

The effectiveness of the flu vaccine varies from season to season. The overall effectiveness depends on how well the flu strains represented in the vaccines match the strains that are circulating throughout flu season, as well as the health and age of the person being vaccinated. According to preliminary data from last year’s flu season, the flu vaccine reduced the risk of illness overall by about 42-43%4. In individuals aged 50 years and older, preliminary vaccine effectiveness was estimated to be 66%.

Why should I get the flu vaccine?

The flu activity during the 2020-2021 and 2021-2022 seasons was low due to mitigation measures in place against COVID-19. As a result, population immunity against the flu is lower this year than it was pre-pandemic. It is more important than ever to get vaccinated this year to avoid what could be a vicious flu season.

Flu vaccination offers many benefits including:

  • Reduced risk of flu illness
  • Reduced severity of illness, hospitalization, and death
  • Protection of vulnerable populations including pregnant women, children, and those with certain chronic health conditions

Are flu vaccines safe?

Yes. Flu vaccines are considered safe and well-tolerated. Mild side effects such as soreness where the shot was injected, low grade fever, or muscle aches are common but short-lived. As with any vaccine, you should contact a medical provider if serious symptoms develop, such as a high fever or signs of a severe allergic reaction.

If I got the flu vaccine last year, do I need to get it again?

It is important to get a flu shot every year, for two main reasons:

  1. Similar to the COVID-19 vaccines, the effectiveness of the flu vaccine can diminish over time.
  2. New strains of the flu emerge each year, and the vaccines are updated to optimize their effectiveness against the current strains.

When is the ideal time to get the flu vaccine?

The ideal time to get the flu vaccine is from October through November, as it takes two weeks for the vaccine to reach maximum efficacy and it typically provides about six months of protection (sufficient for coverage through the flu season running November-May).

Some children are recommended to get two doses of flu vaccine to bolster protection for this season – specifically, children 6 months to 8 years old getting vaccinated for the first time and those who have previously received only one dose of the flu vaccine. For these children, start vaccination as soon as possible since you need to wait at least 4 weeks between doses.

Is there a specific order in which I should get my flu and COVID-19 booster shot?

A recent CDC study published in the Journal of the American Medical Society (JAMA) showed it is safe to get both a COVID 19 booster vaccine and a flu vaccine at the same visit5. The study found there was a ~10% increase in reported systemic reactions, such as fatigue, headache, and muscle aches, when both vaccines were given compared to when the COVID-19 vaccine was given alone. Nevertheless, these side effects were mostly mild and quickly resolved on their own.

If you have not yet received your COVID-19 booster, you can get both your COVID-19 and your flu vaccine at the same time in different injection sites or separate the administration by a few weeks. Whichever approach you choose, most important is that you receive both vaccines, so just get vaccinated however is right for you. If you are due for both vaccines but prefer not to get them at the same time, we suggest prioritizing the COVID-19 shot first given the higher morbidity and mortality of COVID-19 compared to the flu, as well as the continued Omicron surge.

Which COVID-19 vaccine should I get for the best protection?

The updated bivalent boosters are expected to improve protection because they are targeted at circulating variants.


  1. COVID-19 Treatment Guidelines Panel. Coronavirus Disease 2019 (COVID-19) Treatment Guidelines: Influenza and COVID-19.
  2. Merced-Morales, A. et al. Influenza Activity and Composition of the 2022-23 Influenza Vaccine – United States, 2021-22 Season. MMWR Morb. Mortal. Wkly. Rep. 71, 913–919 (2022).
  3. Grohskopf, L. A. Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices — United States, 2022–23 Influenza Season. MMWR Recomm. Rep. 71, (2022).
  4. Seasonal Influenza Vaccine Effectiveness, 2021-2022. (2022).
  5. Hause, A. M. et al. Reactogenicity of Simultaneous COVID-19 mRNA Booster and Influenza Vaccination in the US. JAMA Netw. Open 5, e2222241–e2222241 (2022).

About the Author

Sheley Baylon, PharmD

Senior Director, Research & Head of Pharmacology

Sheley is a licensed doctor of pharmacy with twelve years experience in pharmacy and laboratory research. She deciphers and analyzes medical literature to craft patient-friendly reports, empowering clients with the latest information for informed health decisions.