Pharmacists Play Pivotal Role in Flu Vaccines

The influenza virus causes a respiratory infection that can result in serious complications, predominantly in older adults, young children, and individuals with certain medical conditions, but pharmacists can be great advocates for flu vaccination. Getting a flu shot, although not 100% effective, is the best way of preventing flu and its complications. The CDC recommends annual flu vaccinations for everyone 6 months or older.

It takes approximately 2 weeks to build immunity after a flu shot. Ideally, individuals in the United States should be vaccinated in September or October, with a soft deadline of the end of October. That said, benefits of vaccination remain significant if the shot is given even later in the season. In addition, because flu viruses evolves quickly, a new flu vaccine is released every year.

The FDA held its Vaccines and Related Biological Products Advisory Committee meeting in Silver Spring, Maryland, on March 3, 2022, to select influenza viruses for the composition of the vaccine for the 2022-2023 US influenza season, according to the agency’s website. During this meeting, according to the FDA website, the advisory committee reviewed and evaluated surveillance data pertaining to epidemiology and antigenic characteristics of recent influenza isolates, serological responses to 2021-2022 vaccines, and the availability of candidate strains and reagents.¹ Influenza virus strains were selected based on production method— egg-based vaccines or cell-based/recombinant-based vaccines—according to the website.

The committee recommended that the quadrivalent formulation of egg-based influenza vaccines for the US 2022-2023 influenza season contain: an A/Darwin/9/2021 (H3N2)-like virus; an A/Victoria/2570/2019 (H1N1) pdm09-like virus; a B/Austria/1359417/2021-like virus (B/ Victoria lineage); and a B/Phuket/3073/2013-like virus (B/ Yamagata lineage).¹

The committee recommended that the quadrivalent formulation of cell-based or recombinant-based influenza vaccines for the US 2022-2023 influenza season contain: an A/ Darwin/6/2021 (H3N2)-like virus; an A/Wisconsin/588/2019 (H1N1)pdm09-like virus; a B/Austria/1359417/2021-like virus (B/Victoria lineage); and a B/Phuket/3073/2013-like virus (B/Yamagata lineage).¹

For trivalent influenza vaccines for the US 2022-2023 influenza season, depending on manufacturing method, the committee recommended that the A(H1N1)pdm09, A(H3N2), and B/Austria/1359417/2021-like (B/Victoria lineage) viruses recommended above for the quadrivalent vaccines be used.¹

There are many reasons to get a flu shot every year. Vaccination is the best way of protecting individuals and the community, including those for whom a vaccination is contraindicated, against the flu and its potentially serious complications.

Preventing Illness

The flu vaccine can keep patients from getting sick. This vaccine prevents millions of illnesses and flu-related physician visits and hospitalizations every year. During the 2019-2020 flu season, vaccinations prevented an estimated 7.5 million illnesses, 3.7 million medical visits, 105,000 hospitalizations, and 6300 deaths.² During seasons when flu vaccine viruses are similar to the circulating flu viruses, the flu vaccine has been shown to reduce the risk of doctor visits by 40% to 60%.³

Reducing Severity

The results of a 2021 study indicate that, among adults, flu vaccination was associated with a 26% lower risk of admission to the intensive care unit (ICU) and a 31% lower risk of death from the flu compared with those who were unvaccinated.⁴ The results of a 2018 study show that, among adults hospitalized with the flu, vaccinated patients were 59% less likely to be admitted to the ICU than those who had not been vaccinated. Among adults in the ICU with the flu, vaccinated patients on average spent 4 fewer days in the hospital than those who were not vaccinated.⁵

Chronic Conditions

Flu vaccination has been associated with lower rates of some cardiac events among individuals with heart disease, especially those who have had such an event in the past year.⁶ Flu vaccination can reduce the risk of a flu-related worsening of chronic lung disease, such as chronic obstructive pulmonary disease, requiring hospitalization.⁷

Among individuals with diabetes, flu vaccination has been associated with reduced hospitalizations from a worsening of their illness.⁸

Pregnancy

Flu shots during pregnancy help protect mother and baby from the flu. Vaccination has been shown to halve the risk of flu-associated acute respiratory infection in pregnant women.⁹

The results of a 2018 study show that getting a flu shot reduced a pregnant woman’s risk of being hospitalized with the flu by an average of 40%.⁵ Pregnant women who get a flu vaccine are helping protect their babies from the flu for several months after birth, when they are too young to be vaccinated.

Children

A 2017 CDC study was the first of its kind to show that flu vaccination can significantly reduce a child’s risk of dying from flu.¹⁰

Herd Immunity

Vaccination may also protect the general population, including those who are more vulnerable to serious flu illness: babies and young children, older individuals, and those with certain chronic health conditions.

Despite the many benefits of flu vaccination, only about half of Americans get an annual flu shot, and the flu continues to cause millions of illnesses, hundreds of thousands of hospitalizations, and tens of thousands of deaths.¹¹ Many more individuals could be protected from flu by getting vaccinated.

Pharmacists' Role

Pharmacists play a critical role in protecting patients against seasonal influenza and related complications by advocating for and administrating influenza vaccines and complying with the CDC’s influenza antiviral recommendations. Although clinical practices have limited hours and typically require appointments, pharmacies often have longer hours and many do not require appointments, offering another avenue for patients to get their annual flu shots. When patients express hesitation about getting a flu shot, pharmacists should take the opportunity to identify their concerns and address any misconceptions or questions they have about influenza or influenza vaccination.

About The Author

Kathleen Kenny, PharmD, RPh, has more than 25 years’ experience as a community pharmacist. She is a freelance clinical medical writer based in Homosassa, Florida.

References

1. Influenza vaccine for the 2022-2023 season. FDA. July 6, 2022. Accessed August 12, 2022. https://www.fda.gov/vaccines-blood-biologics/lot-release/influenza-vaccine-2022-2023-season

2. Estimated influenza illnesses, medical visits, and hospitalizations averted by vaccination in the United States — 2019-2020 influenza season. CDC. Updated October 6, 2020. Accessed August 12, 2022. https://www.cdc.gov/flu/about/burden-averted/2019-2020.htm

3. CDC seasonal flu vaccine effectiveness study. CDC. Updated August 3, 2022. Accessed August 12, 2022. https://www.cdc.gov/flu/vaccines-work/effectiveness-studies.htm

4. Ferdinands JM, Thompson MG, Blanton L, Spencer S, Grant L, Fry AM. Does influenza vaccination attenuate the severity of breakthrough infections? A narrative review and recommendations for further research. Vaccine. 2021;39(28):3678-3695. doi:10.1016/j. vaccine.2021.05.011

5. Thompson MG, Kwong JC, Regan AK, et al; PREVENT Workgroup. Influenza vaccine effectiveness in preventing influenza-associated hospitalizations during pregnancy: a multi-country retrospective test negative design study, 2010-2016. Clin Infect Dis. 2019;68(9):1444-1453. doi:10.1093/cid/ciy737

6. Udell JA, Zawi R, Bhatt DL, et al. Association between influenza vaccination and cardiovascular outcomes in high-risk patients: a meta-analysis. JAMA. 2013;310(16):1711-1720. doi:10.1001/ jama.2013.279206

7. Bekkat-Berkani R, Wilkinson T, Buchy P, et al. Seasonal influenza vaccination in patients with COPD: a systemic literature review. BMC Pulm Med. 2017;17(1):79. doi:10.1186/s12890-017-0420-8

8. Vamos EP, Pape UJ, Curcin V, et al. Effectiveness of the influenza vaccine in preventing admission to hospital and death in people with type 2 diabetes. CMAJ. 2016;188(14):E342-E351. doi:10.1503/cmaj.151059

9. Flu and pregnancy. CDC. Updated August 25, 2022. Accessed September 5, 2022. https://www.cdc.gov/flu/highrisk/pregnant.htm#anchor_1565116373

10. CDC study finds flu vaccine saves children’s lives. News release. CDC. Updated April 4, 2017. Accessed August 12, 2022. https://www.cdc.gov/media/releases/2017/p0403-flu-vaccine.html

11. Key facts about seasonal flu vaccine. CDC. Updated August 25, 2022. https://www.cdc.gov/flu/prevent/keyfacts.htm