Influenza in Urgent Care: 2024-2025 Season Update (Pharmacology CME and Infectious Disease CME)

Table of Contents

 

About This Issue

“Influenza-like illness” (ILI) has traditionally been a common presentation at urgent care centers in the fall and winter. Overlapping symptoms of influenza and COVID-19 have changed healthcare-seeking behavior as well as management recommendations for ILI. In this issue, you will learn:

The most common symptoms of influenza in both adults and children

Which patient groups are at high risk for complications from influenza

The current recommendations for influenza vaccination

The impact of the prevalence of influenza in the community on testing decisions, as well as the types of tests available

The indications for antiviral medication

How to determine the most appropriate antiviral medication for each patient

CHARTING & CODING: Knowing how to appropriately document a patient encounter for ILI or confirmed influenza will support the level of care provided. Learn more in our monthly coding column.

1. About This Issue
2. Abstract
3. Case Presentations
4. Introduction
5. Influenza Epidemiology
   1. Types of Outbreaks
   2. Seasonality and Transmission
6. Classification of Influenza Viruses
   1. Avian Influenza
   2. Antigen Variations
7. Influenza Pathophysiology
   1. Influenza Vaccination
      1. Vaccine Formulations
      2. Vaccine Administration
8. Differential Diagnosis
9. Urgent Care Evaluation
10. Diagnostic Studies
11. Treatment
    1. The Neuraminidase Inhibitors
       1. Oseltamivir
       2. Zanamivir
       3. Peramivir
    2. The Adamantane Derivatives
    3. Baloxavir Marboxil
    4. Antiviral Resistance
    5. Chemoprophylaxis for Influenza
    6. Antiviral Use in Pregnant Patients
12. Controversies
    1. Efficacy of Treatment With Antiviral Medications
13. Disposition
14. Time- and Cost-Effective Strategies
15. Summary
16. Risk Management Pitfalls for Managing Influenza in Urgent Care
17. 5 Things That Will Change Your Practice
18. KidBits: Influenza in Pediatric Patients Presenting to the Urgent Care
    1. Clinical Presentation and Diagnosis
    2. Complications
    3. Seasonal Influenza Vaccines
    4. Influenza Treatment
    5. Clinical Pathway for Managing a Pediatric Patient Who Presents to Urgent Care With an Influenza-Like Illness
    6. References
19. Case Conclusions
20. Coding & Charting: What You Need to Know
    1. Determining the Level of Service
       1. Problems Addressed
       2. Complexity of Data
       3. Risk of Complications
    2. Documentation
    3. Coding Formulas for Influenza in Urgent Care
21. Coding Challenge: Influenza in Urgent Care
22. Critical Appraisal of the Literature
23. Clinical Pathways
    1. Clinical Pathway for Managing a Patient Who Presents to Urgent Care With an Influenza-Like Illness
    2. Clinical Pathway for Managing a Patient Who Presents to Urgent Care With an Influenza-like Illness When There is Low Regional Prevalence of Disease
24. Abstract

    Urgent care clinicians should be aware of the most current diagnostic and therapeutic recommendations for influenza and the resources available for guiding management. This review outlines the classification of these viruses, their pathophysiology, the identification of high-risk patients, and the importance of influenza vaccination. Seasonal variations of influenza are discussed, as well as the considerations regarding which patients to test based on the current local prevalence of disease. Given the significant overlap in clinical presentations, co-evaluation for COVID-19 is also briefly discussed in the context of the evaluation and management of influenza. Recommendations for use of the currently available antiviral treatments are discussed, as well as how to engage in shared decision-making with patients regarding risks and benefits of testing and treatment.

    Case Presentations

    CASE 1
    

    A 20-month-old boy presents to the urgent care center with a cough and fever for 2 days...
    • He has no past medical history, and his routine vaccinations are up to date. A COVID-19 rapid antigen test administered at home was negative.
    • His parents say he has been eating less than usual; however, his urine output is normal, and he has had no vomiting or diarrhea.
    • Vital signs are: temperature, 39.6˚C (103.2°F); heart rate, 156 beats/min; respiratory rate, 32 breaths/ min; and oxygen saturation, 100% on room air.
    • He is well-appearing, although his left tympanic membrane is erythematous and bulging, with apparent middle-ear purulence.
    • You make the diagnosis of otitis media in the setting of a presumed viral upper respiratory infection. While preparing the discharge papers, you consider whether testing or treating for influenza would also be appropriate…
    CASE 2
    

    A 34-year-old man presents with cough and fever that started 3 days before…
    • His maximum temperature at home was 40˚C (103.9°F). He has been taking over-the-counter cold remedies without much relief and feels fatigued and “achy all over.”
    • He has no regular primary care provider and has no significant past medical history.
    • His initial vital signs are: temperature, 38.2˚C (102.5°F); heart rate, 108 beats/min; respiratory rate, 20 breaths/min; blood pressure, 134/78 mm Hg; and oxygen saturation, 96% on room air.
    • On examination, he appears uncomfortable and has some tachypnea. The oropharynx is clear and the neck supple. His lungs are clear without any wheezing. The abdomen is soft and nontender.
    • His rapid COVID-19 test returns negative and a chest x-ray reveals no infiltrates.
    • You wonder whether you should also test for influenza, and if so, what type of test, and how reliable would it be? If you test and it’s positive, should you empirically prescribe an antiviral medication or just recommend supportive care?

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    Clinical Pathway for Managing a Patient Who Presents to Urgent Care With an Influenza-Like Illness

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    Key References

    Following are the most informative references cited in this paper, as determined by the authors.

    6. * Mossad SB. Another influenza season in the shadow of the COVID-19 pandemic. Cleve Clin J Med. 2021;88(11):594-597. (Commentary) DOI: 10.3949/ccjm.88a.21095

    27. * World Health Organization. Recommended composition of influenza virus vaccines for use in the 2024-2025 northern hemisphere influenza season. Updated February 23, 2024. (WHO recommendations)

    28. * Grohskopf LA. Ferdinands JM, Blanton LH, Broder KR, Loehr J. Prevention and control of seasonal influenza with vaccines: recommendations of the Advisory Committee on Immunization Practices – United States, 2024-25 influenza season. MMWR Morb Mortal Wkly Rep. 2024;73(No. RR-5):1-25. (Recommendation)

    34. * Greenhawt M, Turner PJ, Kelso JM. Administration of influenza vaccines to egg allergic recipients: a practice parameter update 2017. Ann Allergy Asthma Immunol. 2018;120(1):49-52. (Practice guideline) DOI: 10.1016/j.anai.2017.10.020

    35. * Falsey AR, Treanor JJ, Tornieporth N, et al. Randomized, double-blind controlled phase 3 trial comparing the immunogenicity of high-dose and standard-dose influenza vaccine in adults 65 years of age and older. J Infect Dis. 2009;200(2):172-180. (Randomized controlled trial; 3837 patients) DOI: 10.1086/599790

    38. * Immunization Action Coalition. Ask the Experts: Influenza. Updated September 5, 2024. Accessed November 11, 2024. (Website)

    39. * Kroger A, Bahta L, Long S, Sanchez P. General Best Practice Guidelines for Immunization. Best Practices Guidance of the Advisory Committee on Immunization Practices (ACIP). Updated July 22, 2024. Accessed on November 11, 2024. (Practice recommendations)

    40. * Toback S, Galiza E, Cosgrove C, et al. Safety, immunogenicity, and efficacy of a COVID-19 vaccine (NVX-CoV2373) co-administered with seasonal influenza vaccines: an exploratory substudy of a randomised, observer-blinded, placebo-controlled, phase 3 trial. Lancet Respir Med. 2022;10(2):167-179. (Randomized controlled trial; 400 patients) DOI: 10.1016/S2213-2600(21)00409-4

    49. * Peltola V, Ziegler T, Ruuskanen O. Influenza A and B virus infections in children. Clin Infect Dis. 2003;36(3):299-305. (Retrospective study; 15,420 patients) DOI: 10.1086/345909

    50. * Lim WS. Pandemic flu: clinical management of patients with an influenza-like illness during an influenza pandemic. Provisional guidelines from the British Infection Society, British Thoracic Society, and Health Protection Agency in collaboration with the Department of Health. Thorax. 2007;62(Suppl 1):1-46. (Clinical practice guidelines – UK) DOI: 10.1136/thx.2006.073080

    51. * Uyeki TM, Bernstein HH, Bradley JS, et al. Clinical practice guidelines by the Infectious Diseases Society of America: 2018 update on diagnosis, treatment, chemoprophylaxis, and institutional outbreak management of seasonal influenza. Clin Infect Dis. 2019;68(6):e1-e47. (Clinical practice guideline) DOI: 10.1093/cid/ciy874

    63. * Uyeki TM. Influenza diagnosis and treatment in children: a review of studies on clinically useful tests and antiviral treatment for influenza. Pediatr Infect Dis J. 2003;22(2):164-177. (Systematic review)

    65. * Ozaras R, Cirpin R, Duran A, et al. Influenza and COVID-19 coinfection: report of six cases and review of the literature. J Med Virol. 2020;92(11):2657-2665. (Case reports and literature review; 6 patients) DOI: 10.1002/jmv.26125

    83. * Jefferson T, Demicheli V, Rivetti D, et al. Antivirals for influenza in healthy adults: systematic review. Lancet. 2006;367(9507):303-313. (Systematic review; 51 randomized controlled trials) DOI: 10.1016/S0140-6736(06)67970-1

    84. * Jefferson T, Demicheli V, Di Pietrantonj C, et al. Amantadine and rimantadine for influenza A in adults. Cochrane Database Syst Rev. 2006;2006(2):CD001169. (Cochrane review; 20 prophylaxis trials, 13 treatment trials) DOI: 10.1002/14651858.CD001169.pub3

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    Keywords: : influenza, flu, influenza-like illness, vaccine, H1N1, H3N2, H5N1, epidemic, pandemic, COVID-19, co-infection, vaccination, antiviral, oseltamivir, zanamivir, peramivir, baloxavir, neuraminidase inhibitors, rapid influenza test, RT-PCR, prevalence, resistance, chemoprophylaxis