A Student Pharmacist's Guide to the Flu Vaccine

We all dread the signs every flu season: runny nose, sore throat, muscle aches, and fever. Among pharmacy students, influenza is a cause not only for missed classes but also for numerous regrets about not getting a flu shot sooner. As future health care providers, student pharmacists must have a thorough understanding of influenza and how patients can prevent it via immunization.

The term influenza refers to hundreds of virus strains in the same family that cause a similar reaction in the body but interact with the immune system in different ways.¹ There are 4 types of the influenza virus: A, B, C, and D. Type A affects humans and a host of other animals that live in close proximity to us, such as pigs and birds; this type is primarily to blame for epidemics, although type B is known to cause concentrated outbreaks. Influenza A and B are the 2 influenza viruses that are vaccinated against seasonally. Type C is not prevalent in public health and does not pose a serious threat, and Type D does not affect humans.^1,2

According to the World Health Organization, virologists from around the world meet twice a year as part of the Global Influenza Surveillance and Response System (GISRS) to analyze influenza data collected from clinics worldwide in an effort to predict and curtail the most prevalent strains of that year.³ The GISRS made its recommendations for the 2018-2019 flu season in the Northern hemisphere on February 22, 2018. The recommendations for the current quadrivalent vaccine are: A(H1N1)pdm09-like virus, A(H3N2)-like virus, B/Victoria/2/87 lineage, and B/Yamagata/16/88 lineage. The strain of A(H3N2) from this year was more susceptible to the vaccine during trials compared with last year’s.³

Many manufacturers produce the normal injection for distribution in pharmacies, as well as a high-dose version for patients 65 years and older. Patients who are older or have compromised or weakened immune systems are considered to be at higher risk for complications stemming from influenza, including minor ones like sinus and ear infections as well as more serious coinfections such as pneumonia.⁴ Complications in higher-risk groups can lead to hospitalization and even death, with influenza responsible for up to 3 million to 5 million cases of severe illness and 290,000 to 650,000 deaths worldwide each year.²

Although some patients may be hesitant to receive the influenza vaccine, pharmacists have an essential role to play in explaining the importance of immunization and alleviating their concerns. One common reason patients give for not vaccinating themselves is fear of adverse effects. As with all most forms of medication, the influenza vaccine is not free of adverse effects, and its administration is commonly associated with bruising or soreness at the injection site. Newly immunized patients may also feel as though they are developing the flu, but the virus in the vaccine cannot replicate because of a lack of RNA. Rather, feeling sick after receiving a flu shot is the result of the body’s creating antibodies against the antigens introduced by the vaccine. Explaining how the vaccine works to patients who are unsure about receiving the shot can build trust and help put them at ease.

A flu shot provides valuable protection against influenza, but it is not perfect, and patients can still contract the virus after being vaccinated. Therefore, it is also important to advise patients on how to minimize their risk after receiving the shot, such as by avoiding those who are sick, washing their hands frequently, and covering coughs and sneezes.⁴ Notably, patients are most contagious in the first 3 to 4 days after contracting the virus, with some individuals infecting others 1 day prior to the onset of symptoms and up to a week after becoming sick.⁴

Many believe they will be fine without a flu shot, but that is simply not a risk worth taking, as the influenza vaccine can minimize or prevent flu symptoms while halting transmission of the virus, resulting in an overall healthier community. Vaccines are the cornerstone of modern medicine, weeding out diseases that once proved fatal, and although the influenza vaccine may not eradicate or cure the flu, it nevertheless provides a myriad of benefits that pharmacists can explain to their patients.

Philip Moliterno is a 2020 PharmD candidate at the St. John’s University College of Pharmacy and Health Sciences.

References

• Influenza. Encyclopedia Britannica website. britannica.com/science/influenza. Accessed August 31, 2018.
• Influenza (seasonal). World Health Organization website. who.int/en/news-room/fact-sheets/detail/influenza-(seasonal). Published January 31, 2018. Accessed August 31, 2018.
• WHO consultation and information meeting on the composition of influenza virus vaccines for use in the 2018-2019 Northern hemisphere influenza season. World Health Organization website. who.int/influenza/vaccines/virus/recommendations/consultation201802/en. Updated February 22, 2018. Accessed August 31, 2018.
• Influenza (flu). CDC website. cdc.gov/flu/keyfacts.htm. Updated August 27, 2018. Accessed August 31, 2018.