Infectious Disease I: Influenza - PowerPoint Presentation

1. Infectious Disease I:InfluenzaCourses in Therapeutics and Disease State Management

2. Learning Objectives (Slide 1 of 3)Differentiate between influenza A and influenza BList the primary subtypes of influenza A that are currently circulatingDifferentiate between antigenic drift and antigenic shiftIdentify the virus characteristics necessary for a pandemicDiscuss the transmission of the influenza virus

3. Learning Objectives (Slide 2 of 3)Evaluate the infectivity of adults and children with influenza infectionList the signs and symptoms of influenza illnessDescribe the diagnostic tests available for influenzaDifferentiate the populations at high risk for complications or severe influenza infection from the general populationCompare and contrast the trivalent influenza vaccine (TIV) and the live-attenuated influenza vaccine (LAIV), and the different formulations available

4. Learning Objectives (Slide 3 of 3)Discuss the emergence of variant influenza A H3N2 and treatment and prevention recommendations for this virusDiscuss options available for prevention of influenza infectionCompare and contrast the antiviral agents available for prophylaxis and treatment of influenzaFormulate a post-exposure prophylaxis plan given patient-specific dataRecommend an appropriate treatment regimen for influenza based on patient-specific data

5. Required ReadingNjoku JC, Hermsen ED. Chapter 87. Influenza. In: DiPiro JT, Talbert RL, Yee GC, Matzke GR, Wells BG, Posey L. eds. Pharmacotherapy: A Pathophysiologic Approach, 9e. New York, NY: McGraw-Hill; 2014.

6. Influenza Overview (Slide 1 of 2)Acute respiratory illness caused by infection with influenza virusesCauses significant morbidity and mortality in patients infectedAnnual seasonal outbreaks generally occur from October to May, but can occur at anytime of the year

7. Influenza Overview (Slide 2 of 2)Only two types of Influenza virus cause disease in humansType AHemagglutinin subtypesH1H3Neuraminidase N1N2Type BGenetic variation leads to seasonal outbreaksPoint mutationsAntigenic shiftInfluenza pandemics can have a high mortality rate

8. PathophysiologyTransmission Aerosols CoughsSneezesContact Hand-to-handPersonal contactFomite transmissionIncubation period 1 to 7 daysPathogenesis is not well understoodSeverity of illness variesViral ReplicationHost defense response

9. Clinical PresentationSigns and Symptoms Rapid onset of one or more of the followingFeverMyalgiaHeadacheMalaiseNonproductive coughSore throatRhinitisLaboratory/Diagnostic TestsWBC countViral CultureRapid antigen testDirect fluorescence antibody (DFA)Reverse-transcription polymerase chain reaction (RT-PCR) Cultures for bacterial coinfectionChest X-ray

10. Treatment OverviewPromote prevention measures Early identification of influenzaAdministration of antiviral therapies with 48 hours of symptom onset for best results Supportive care with hydration, antihistamines, and antipyretics

11. Nonpharmacological Prevention and TreatmentHand hygieneBasic respiratory etiquetteCover mouth when coughing/ sneezingThrow away tissuesAdequate SleepMaintain low activity level

12. Pharmacological PreventionVaccination Primary means of influenza prevention in the United StatesIdeal vaccination administration is during October or NovemberSpecific strains in available vaccines change each year based on antigenic shiftAll patients ages 6 months and older should be vaccinated Chemoprophylaxis Neuraminidase inhibitorsOseltamivirZanamivirUtilized as post exposure prophylaxis

13. Pharmacological PreventionVaccination Multiple products and manufacturers Trivalent influenza vaccines:Contains  two influenza A subtypes (H3N2 and H1N1) and 1 influenza B virus subtypeStandard dose:Inactivated Egg-based: Inactivated Recombinant: High dose (egg-based)Quadrivalent influenza vaccines:Contains  two influenza A subtypes (H3N2 and H1N1) and 2 influenza B virus subtypesInactivated (egg-based)Inactivated (cell cultured)Live-attenuated, intranasal

14. Pharmacological PreventionChemoprophylaxisShould only be used in patients that cannot receive vaccinationCan be taken throughout the entire duration of influenza activity in the community Live attenuated influenza vaccine should not be administered within 48 hours of stopping antiviral therapy

15. Pharmacological TreatmentOveruse of the adamantanes (amantadine and rimantadine) has lead to viral resistance to this class of medications for the treatment of Influenza A (H1N1)Neuraminidase inhibitors are the only antiviral drugs available for treatment and prophylaxis of influenzaOseltamivir ZanamivirPeramivir

16. Pharmacological Treatment (Slide 2 of 2)DrugAdult TreatmentAdult Prophylaxis aPediatric Treatment Pediatric Prophylaxis Oseltamivirb75-mg capsule twice daily for 5 days75-mg capsule daily2 weeks-1 year: 3 mg/kg BID≥1 year≤15 kg: 30 mg BID16–23 kg: 45 mg BID23–40 kg: 60 mg BID>40.1 kg: 75 mg twice BIDAll for 5 days2 weeks-1 year: not recommended≥1 year≤15 kg: 30 mg daily16–23 kg: 45 mg daily23–40 kg: 60 mg daily>40.1 kg: 75 mg dailyAll for 10 daysZanamivir2 inhalations twice daily for 5 days2 inhalations dailyc2 inhalations twice daily × 5 days for ≥7 years old2 inhalations daily for ≥5 years oldPeramivir600 mg IV as a single doseN/AN/AN/AaIf influenza vaccine is administered, prophylaxis can generally be stopped 14 days after vaccination for noninstitutionalized persons. When prophylaxis is being administered following an exposure, prophylaxis should be continued for 10 days after the last exposure. In persons at high risk for complications from influenza for whom vaccination is contraindicated or expected to be ineffective, chemoprophylaxis should be continued for the duration that influenza viruses are circulating in the community during influenza season.b Dose adjustments required in renal impairmentc Duration for household setting prophylaxis is 10 days and for community outbreak setting is up to 28 days

17. Overall MonitoringMonitor for relief of signs and symptomsSecondary bacterial infection may have occurred ifWorsening of symptoms 7 days from onsetProlonged symptoms past 10 days from onsetRecommend follow up with physician

18. SummaryInfluenza can cause significant morbidity and mortalityPrevention of influenza via vaccination is the mainstay of therapyChemoprophylaxis can be utilized in patients that can not or have not yet received a vaccinationEarly detection is important to ensure early initiation of Neuraminidase inhibitors Oseltamivir, or Zanamivir, or Peramivir

19. References Njoku JC, Hermsen ED. Chapter 87. Influenza. In: DiPiro JT, Talbert RL, Yee GC, Matzke GR, Wells BG, Posey L. eds. Pharmacotherapy: A Pathophysiologic Approach, 9e. New York, NY: McGraw-Hill; 2014.Grohskopf LA, Sokolow LZ, Broder KR, et al. Prevention and Control of Seasonal Influenza with Vaccines. MMWR Recomm Rep 2016;65(No. RR-5):1–54. TAMIFLU® (oseltamivir phosphate) [package insert]. South San Francisco, CA: Genentech, Inc.; 2016.RELENZA (zanamivir) [package insert]. Research Triangle Park, NC: GlaxoSmithKline; 2016.RAPIVAB™ (peramivir injection) [package insert]. Durham, NC: BioCryst Pharmaceuticals, Inc.; 2016.