Influenza Season 2018-2019

Case study: On a brisk day in early December, your clinic is packed with patients. It seems like everyone returned from the Thanksgiving holidays with upper respiratory symptoms. For example, the next patient you are slated to see is an otherwise healthy 20-year-old college student who is presenting to clinic with chief complaints of “fever, runny nose, and cough.” When you walk into the exam room, you see a young man asleep in a chair in the corner of the room. You gently wake him up, and he looks up blearily and miserably at you. He introduces himself as Ian, and says that he feels terrible. What do you ask Ian?

You ask Ian to tell you why he feels terrible. Ian tells you that he woke up this morning with a terrible headache and so exhausted that he could barely get out of bed. He had a sore throat last night, but this morning has also developed a runny nose and cough. The reason he came to clinic, though, is because he borrowed his roommate’s thermometer and saw that he had a 103 degree fever. When he called his mother, she told him to go to the doctor. According to Ian, everyone who attended Thanksgiving dinner from his extended family seems to have “caught something.” He denies nausea, vomiting, or diarrhea. He has not had a flu shot this year, but is otherwise up-to-date on his vaccinations. On physical exam, Ian is febrile to 102.9 and has a heart rate of 110 beats per minute. His eyes are red, his nose has mucus impeding visibility, and his sinuses are tender to palpation. His throat is slightly red, his heart rate is slightly fast but rhythm is normal, breath sounds are clear bilaterally, and he does not have any abdominal tenderness. You look in both ears with your otoscope and do not appreciate any erythema or drainage. The patient does not have any palpable lymphadenopathy. What do you do next?

You tell Ian that there are a lot of viral and bacterial infections going around this time of year. Because it is still early in the disease process, you will not prescribe antibiotics for now. However, you do want to screen him for influenza because your community has seen an uptick in cases over the past few weeks. You will also send a swab for strep throat. You send him home with instructions to maintain hydration, take acetaminophen for fever, and get some rest. An hour later, the lab calls you to say that Ian tested negative for strep but positive for flu. You call Ian back and tell him you have called in a prescription for an antiviral medication that will decrease the duration and severity of influenza if given within 48 hours of symptom onset. Treatment options include oseltamivir, zanamivir, peramivir, and the recently approved baloxavir marboxil.

 What do we know about the 2018-2019 flu season?

The flu season is predicted to start in October and last until May in the United States. This year’s trivalent flu vaccine covers H1N1, H3N2, and the Victoria-lineage strains of influenza. The quadrivalent flu vaccine also includes the Yamagata lineage strain. The CDC recommends that people ages 6 months and older obtain a flu vaccine and this vaccine could be the standard dose trivalent or quadrivalent flu shot, the high dose flu shot for older adults who might not have as robust a response to the standard shot, or the live attenuated influenza vaccination (nasal spray vaccine).

Patients have wide array of options for flu vaccines this year, including a quadrivalent cell-based flu vaccine that is egg-free. Some of the flu vaccines are limited to people of certain ages. For example, the recombinant flu vaccine has been approved for people older than 18 years old, and the adjuvant and high dose flu shot are approved for people over age 65. The flu vaccine is currently contraindicated for babies less than 6 months old and for people with severe allergic reactions to components of the flu vaccine. People with a prior history of Guillain-Barré Syndrome or egg allergy should talk with a physician or nurse practitioner before getting the vaccine. The nasal spray vaccine is contraindicated for children less than 2 years old and pregnant women. Additionally, children receiving the flu vaccine for the first time require 2 doses spaced a month apart. Even though it is optimal to receive the flu vaccine before October, people can receive the vaccine well into flu season and see a preventive or protective effect. Lastly, patients should be counseled that they cannot get the flu from receiving the flu shot.

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Dr. V. Silverstein
Durham, NC

Published on 12/10/18