Flu Season Is Around the Corner: What You Need to Know

Influenza is an acute respiratory illness caused by viruses that invade the nose, throat, and lungs. There are multiple types of influenza viruses, classified first by the antigenic properties of nucleoprotein and matrix protein antigens, as A, B, or C. Influenza A viruses are subtyped by surface hemagglutinin (H) and neuraminidase (N) antigen. Each A strain is further designated according to the site of origin, isolate number, year of isolation, and subtype. For example, this year’s influenza vaccine includes the A/Michigan/45/2015 (H1N1)pdm09-like virus as one of the A strains. B and C viruses are named in a similar manner but do not receive subtype classifications. There is not as much variation within the B viruses, and there may be no variation with the C viruses.

Outbreaks of influenza are recorded almost every year, with wide fluctuations in the extent and severity. The most severe outbreaks involve influenza A viruses, as the H and N antigens mutate frequently, by undergoing antigenic shifts or drifts. An antigenic shift is a major variation and may be associated with pandemics, while minor variations are known as drifts. These mutations make it essential for the composition of influenza vaccines to be reviewed each year and matched to the most commonly circulating viruses.¹

Influenza virus infection can cause mild to severe illness. The number of people hospitalized related to influenza in the United States has ranged from 140,000 to 710,000, and deaths from 12,000 to 56,000, annually since 2010, according to CDC estimates. Symptoms vary but can include fever/chills, cough, sore throat, congestion, runny nose, body aches, headache, and fatigue.

The onset is usually abrupt, and respiratory symptoms, such as a cough, may persist for 1 to 2 weeks. Complications of influenza can include pneumonia, sinusitis, otitis media, and worsening of chronic obstructive pulmonary disease and asthma.²

Most healthy people recover without complications. However, the following groups are at increased risk of complications from influenza infection:

• Those older than 65
• Individuals with asthma, diabetes, heart disease, other chronic diseases, or who are immunocompromised
• Pregnant women
• People who are extremely obese, with a body mass index greater than 40
• Children younger than 5
• Native Americans or Alaska natives
• Those who are residents of long-term-care facilities
• Children who are between 6 months and 18 years who take aspirin or salicylates, due to the risk of Reye Syndrome

Influenza diagnosis during a known outbreak can be made with a high degree of certainty based upon findings during physical assessment. In the absence of an outbreak, there are specific laboratory tests that are used to detect the influenza virus. These tests include rapid influenza diagnostic tests, rapid molecular assay, immunofluorescence, reverse transcription polymerase chain reaction, rapid cell culture, or viral tissue cell culture. Results are most accurate when testing is completed less than 3 to 4 days after the onset of symptoms. The results can be helpful in cases where the information obtained can identify an outbreak of a particular strain. If the patient is pregnant or immunocompromised, results may help guide treatment decisions. ³

Treatment of uncomplicated influenza involves rest, fluids, and symptom management. Acetaminophen is the drug of choice for fever and myalgia. Salicylates should be avoided in children under 18 due to the risk of Reye’s syndrome. Cough suppressants are not recommended unless the cough is bothersome. Antihistamines and decongestants may be considered for nasal symptoms. Advise patients to stay home from work or school until they have been afebrile for 24 hours.

Antiviral medications are available for those at high risk of complications from influenza. These products are most effective when started within 2 days of symptom onset and can help to decrease the severity of influenza symptoms. Antivirals can also prevent serious complications, such as pneumonia, from developing and thus decreasing the possibility of hospitalization in high-risk patients. ⁴ Oseltamivir is available generically, and as recently as this week, FDA officials cleared Nesher Pharmaceuticals' oseltamivir phosphate for oral suspension, 6 mg (base)/mL to treat influenza types A and B in patients 2 weeks of age and older who have had flu symptoms for no more than 2 days, and to prevent the flu in patients one year of age and older. Oseltamivir is also available as the brand Tamiflu in tablet or oral solution form. Zanamivir is available as the brand Relenza and is an inhaled powder. Peramivir is administered intravenously and is available as the brand product Rapivab.⁵

Everyday preventive habits can help slow the spread of influenza and other viruses. Remind patients to avoid close contact with those who are sick and stay at home if they are sick. They should tell patients to wash hands with soap and water frequently or clean hands with an alcohol-based hand rub if soap and water are not available; avoid touching the eyes, nose, mouth, and cleaning surfaces and objects that may be contaminated; and cover the nose and mouth when sneezing or coughing to limit the spread of viruses.⁶

Obtaining an annual influenza vaccine is the most effective way to prevent morbidity and mortality from influenza. The CDC continues to recommend that everyone 6 months and older get an influenza vaccine, by the end of October if possible, if no contraindications are present. The intranasal vaccine, found to be less effective than the injectable vaccine, is no longer recommended.

This year’s trivalent vaccine includes the following strains of attenuated virus: A/Michigan/45/2015 (H1N1)pdm09-like virus; A/Hong Kong/4801/2014 (H3N2)-like virus; and B/Brisbane/60/2008-like virus (Victoria lineage). Four-component vaccines (quadrivalent), which protect against a second type of B virus, include the same viruses recommended for the trivalent vaccines, as well as a B/Phuket/3073/2013-like virus (Yamagata lineage). Other types of vaccine include a quadrivalent egg- free vaccine (Flublok) and a quadrivalent cell-cultured vaccine (Flucelvax). Antibodies to the H antigen produce immunity to the influenza virus, and those to the N antigen limit the spread of the virus in the body and help reduce infection.¹

Adults older than 65 can have weakened immune systems and thus, a lower response to standard-dose influenza vaccines. Fluzone High-Dose contains 4 times the amount of antigen than its regular-dose counterpart to produce a greater immune response. Fluad is a trivalent vaccine adjuvanted with MF59, an oil-in-water emulsion of squalene oil. Squalene is a naturally occurring substance found in plants, animals, and humans. This oil-in-water adjuvant produces a greater immune response and causes the product’s milky white appearance.

The type of vaccine administered depends on availability, patient-specific parameters, and often, insurance coverage. The CDC does not make a preferential recommendation for 1 influenza vaccine over another for those in whom more than one licensed, recommended product is available. Consider the following tips when selecting an influenza vaccine for patients:

• FluLaval Quadrivalent and Fluzone Quadrivalent are indicated for infants older than 6 months.
• For children 6 months through 8 years who need 2 doses of influenza vaccine, get the first dose as soon as possible after the vaccine becomes available, to ensure that they get their second dose by the end of October.
• Pregnant women may receive any licensed, recommended, age-appropriate influenza vaccine.
• The influenza vaccine can be administered at the same time as other vaccines. Separate the injection sites by at least 1 inch if administering in the same arm.
• Fluad and Fluzone High-Dose are indicated for patients 65 and older. However, this group may be vaccinated with standard dose vaccines. Vaccination should not be delayed if a specific product is not available.
• Flucelvax contains only a small amount of egg protein, compared with other inactivated vaccines.
• Flublok is egg-free.
• Patients whose only reaction to eggs is hives may be vaccinated with any influenza vaccine. Patients with allergy symptoms other than hives, including angioedema, respiratory distress, lightheadedness, recurrent vomiting, or the need for emergency treatment, should be vaccinated in a medical setting, such as a physician’s office or hospital, under the supervision of a health care professional who can recognize and treat severe allergic reactions. Patients should be observed for adverse reactions for 15 minutes after vaccination.
• Prior severe allergic reaction to influenza vaccine, regardless of suspected component, is a contraindication to future influenza vaccination.
• General precautions to influenza vaccination include severe acute illness with or without fever, or a history of Guillain-Barre Syndrome within 6 weeks following a prior influenza vaccination.⁷

Pharmacists provide patient education every day. It is especially important that they provide education about vaccines and the illnesses against which they protect and debunk any myths that persist, despite educational campaigns. Many parents fear that vaccines may cause autism or that multiple vaccines might overwhelm a child’s immune system. Some patients have fear and anxiety about pain from the vaccine or potential adverse effects. Others may think that they may become sick from the influenza vaccine. Finally, there are those who say, “I am healthy. I never get sick. Why do I need a vaccine?” Motivational interviewing (MI) is an effective tool for communicating with patients that lets them decide if they will receive the influenza vaccine. MI allows the development of a rapport with the patient and a chance to reframe information or educate the patient in such a way that they do not feel as if they are being lectured. Asking permission to provide educational information, then asking the patient what they think of the information is an effective way of including the patient in the decision-making process. This technique involves asking open-ended questions, listening, and then reflecting the patient’s concerns. At the end of this dialogue, it is important to summarize the issue and set a goal for the patient, based upon something that is important to them, such as a wedding or the birth of a grandchild.⁸

Pharmacists play an important role in keeping communities healthy during flu season. Take the time to listen to patients’ concerns. It is important to provide a solid, positive recommendation and be ready to address the most common concerns that patients have about influenza, flu vaccines, or other vaccinations.

References

• Dolin R, Influenza. In: Kasper DL, Braunwald E, Fauci AS, et al., eds. Harrison’s Principles of Internal Medicine. 16th ed. New York, NY: McGraw Hill; 2005:1066-1071.
• Disease burden of influenza. CDC. www.cdc.gov/flu/about/disease/burden.htm. Updated May 16, 2017. Accessed August 28, 2017.
• Influenza virus testing methods. CDC. www.cdc.gov/flu/professionals/diagnosis/table-testing-methods.htm. Updated September 23, 2016. Accessed August 28, 2017.
• What you should know about flu antiviral drugs. CDC. www.cdc.gov/flu/antivirals/whatyoushould.htm. Updated January 5, 2017. Accessed September 6, 2017.
• Flu Treatment. CDC. www.cdc.gov/flu/treatment/index.html. Updated July 28, 2017. Accessed August 28, 2017.
• CDC says “take 3” actions to fight the flu. CDC. www.cdc.gov/flu/protect/preventing.htm Updated September 11, 2017. Accessed September 15, 2017.
• CDC. Prevention and control of seasonal influenza with vaccines: recommendations of the advisory committee on immunization practices — United States, 2017-18 influenza season. www.cdc.gov/mmwr/volumes/66/rr/rr6602a1.htm?s_cid=rr6602a1.htm. Published August 25, 2017. Accessed September 15, 2017.
• Berger BA, Villaume WA. Motivational Interviewing for Healthcare Professionals: A Sensible Approach. 1st edition. Washington: American Pharmacists Association; 2013.