influenza and influenza vaccines

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Influenza and Influenza Vaccines. K. Vahdat 25/11/1391. Influenza. Highly infectious viral illness Epidemics reported since 16 th century. Influenza Virus Strains. Type A moderate to severe illness all age groups humans and other animals Type B changes less rapidly than type A - PowerPoint PPT Presentation


  • Influenza and Influenza VaccinesK. Vahdat25/11/1391

  • InfluenzaHighly infectious viral illness Epidemics reported since 16th century

  • Influenza Virus StrainsType A moderate to severe illnessall age groupshumans and other animals Type Bchanges less rapidly than type A milder epidemicshumans onlyprimarily affects children

  • Subtypes of type A determined by hemagglutinin (H) and neuraminidase (N)Influenza Type A Subtypes

  • Surface Antigens and ImmunityImmunity reduces likelihood of infection and severity of disease.Antibodies are specific to different types of surface antigens.Changes in H and N allow virus to evade previously developed immune responses.Antigenic changes: drift and shift.

  • Influenza Antigenic ChangesAntigenic DriftMinor change, same subtypeCaused by point mutations in geneMay result in epidemic

    Example of antigenic driftIn 2003-2004, A/Fujian/411/2002-like (H3N2) virus was dominantA/California/7/2004 (H3N2) began to circulate and became the dominant virus in 2005

  • Influenza Antigenic ChangesAntigenic ShiftMajor change, new subtypeCaused by exchange of gene segmentsMay result in pandemic

    Example of antigenic shiftH2N2 virus circulated in 1957-1967H3N2 virus appeared in 1968 and completely replaced H2N2 virus

  • Burden of Influenza10% to 20% of the population is infected with influenza virus each year.Average of more than 200,000 excess hospitalizations each year.Persons 65 and older and 2 years and younger at highest riskAverage of 36,000 deaths each year.Persons 65 and older at highest risk of death

  • Influenza EpidemiologyReservoir Human, animals (type A only) Transmission Respiratory Probably airborne Temporal pattern Peak December - March in temperate area May occur earlier or later

    Communicability Maximum 1-2 days before to 4-5 days after onset

  • Influenza VaccinesInactivated subunit (TIV)IntramuscularTrivalentAnnual

    Live attenuated vaccine (LAIV)IntranasalTrivalentAnnual

  • Influenza Vaccine SupplyManufacturerDoses Projected*

    GSK 30-35 millionMedImmune 7 millionNovartis 40 millionsanofi pasteur 50 millionCSL No estimate providedTotal Up to 127-132 m

  • influenza vaccines for 201213 contain: A/California/7/2009 (H1N1)-like, A/Victoria/361/2011 (H3N2)-like, B/Wisconsin/1/2010-like (Yamagata lineage) antigens. Children aged 6 months through 8 years require 2 doses of influenza vaccine (administered a minimum of 4 weeks apart) during their first season of vaccination to optimize immune response.

  • Inactivated Influenza Vaccines*inactivated vaccines approved for children younger than 4 years

    VaccinePackageDoseAgeThimerosalFluzone(sanofi pasteur)Multidose vial*Age-dependent>6 mosYes Single dose syringe*0.25 mL6-35 mosNo Single dose syringe*0.5 mL>36 mosNo Single dose vial*0.5 mL>36 mosNoFluvirin(Novartis)Multidose vial0.5 mL>4 yrsYesFluarix(GSK)Flulaval(GSK)Single dose syringeMultidose vial0.5 mL

    0.5 mL>18 yrs

    >18 yrsTrace


  • Afluria Influenza VaccineTrivalent inactivated vaccine produced in hens eggsApproved for persons 18 years and olderAvailable inPreservative-free prefilled syringeMultidose vialSimilar adverse reaction profile as other inactivated influenza vaccines

  • Why a Yearly Influenza VaccinationInfluenza vaccine expires June 30 (10 Tir) each year.

    Antibodies wane during the year.

    Surface antigens drift and shift.

  • Inactivated Influenza Vaccine Efficacy70% - 90% effective among healthy persons
  • Inactivated Influenza Vaccine Adverse ReactionsLocal reactions15% - 20%

    Fever, malaiseuncommon

    Allergic reactionsrare

    Neurologicalvery rare reactions

  • Inactivated Influenza Vaccine Adverse ReactionsInactivated influenza vaccine contains only noninfectious fragments of influenza virusInactivated influenza vaccine cannot cause influenza disease

  • AgeGroup6-35 mos

    3-8 yrs

    9 yrs and older

    Dose0.25 mL

    0.50 mL

    0.50 mLNo.Doses1 or 2 (4 week interval)

    1 or 2(4 week interval)


  • LAIV EfficacyAgainst lab-confirmed influenza following experimental challengeLAIV 85% effectiveTIV 71% effectiveNo significant difference

  • Live Attenuated Influenza Vaccine Adverse ReactionsChildrenNo significant increase in URI symptoms, fever, or other systemic symptomsIncreased risk of asthma or reactive airways disease in children 12-59 months of ageAdultsIncreased rate of cough, runny nose, nasal congestion, sore throat, and chills reported among vaccine recipientsNo increase in the occurrence of fever No serious adverse reactions identified

  • LAIV IndicationsHealthy* persons 5 49 years of age Close contacts of persons at high risk for complications of influenza (except severely immunosuppressed)Persons who wish to reduce their own risk of influenzaHealthcare workers*Persons who do not have medical conditions that increase their risk for complications of influenza

  • LAIV ScheduleAgeGroup6 mos 8 years

    9 yrs and olderDose0.2 mL

    0.2 mL

    No.Doses1 or 2 (4 week interval)


  • Transmission of LAIV VirusLAIV replicates in the NP mucosaMean shedding of virus 7.6 days longer in childrenOne instance of transmission of vaccine virus documented in a day care settingTransmitted virus retained attenuated, cold adapted, temperature sensitive characteristicsTransmitted attenuated vaccine virus unlikely to cause typical influenza symptoms

  • Use of LAIV Among Healthcare PersonnelNo instances of transmission of LAIV have been reported in the U.S.ACIP recommends that LAIV can be given to eligible HCWs except those that care for severely immuno-suppressed persons (hospitalized and in isolation)No special precautions are required for HCWs who receive LAIV

  • LAIV StorageMust be stored at 35 - 46 degrees FahrenheitSimilar to TIVIf inadvertently frozen, return to refrigerator

  • TIV preparations, with the exception of Fluzone Intradermal (Sanofi Pasteur), should be administered intramuscularly. Fluzone Intradermal is indicated for persons aged 18 through 64 years The intranasally administered live-attenuated influenza vaccine (LAIV), FluMist (MedImmune), is indicated for healthy, nonpregnant persons aged 2 through 49 years

  • No preference is indicated for LAIV versus TIV in this age group Persons with a history of egg allergy should receive TIV rather than LAIV.

  • Influenza SeasonRecommended Groups for VaccinationChildren 6-59 months of ageHealthy adults 50 years old and olderPersons 5 49 years old at high risk for complicationsPregnant womenResidents of nursing homesHousehold contacts of persons at high risk for complicationsHealth care workers

  • Influenza: High Risk for ComplicationsBirth through 59 months of ageAdults 50 years old and olderChronic lung disease, asthmaChronic heart diseaseMetabolic diseases, e.g. diabetesChronic renal diseaseHigh risk of aspirationImmunosuppressionPregnancyChronic aspirin therapy: 18 years old and younger

  • HIV Infection and Inactivated Influenza VaccinePersons with HIV at higher risk for complications of influenzaTIV induces protective antibody titers in many HIV-infected personsTransient increase in HIV replication reportedTIV will benefit many HIV-infected persons

  • Pregnancy and Inactivated Influenza VaccineRisk of hospitalization 4 times higher than nonpregnant womenRisk of complications comparable to nonpregnant women with high risk medical conditionsVaccination (with TIV) recommended for all women who will be pregnant during the influenza season, regardless of gestational age

  • Influenza Vaccine RecommendationsImmunization providers should administer influenza vaccine to any person who wishes to reduce the likelihood of becoming ill with influenza or transmitting influenza to others*Healthy persons 5-49 years of age, including healthcare personnel may receive either TIV or LAIV

  • New Influenza Vaccine RecommendationChildren 6 months through 8 years being vaccinated for the first time should receive TWO dosesSome children do not return for the second doseBeginning in influenza season 2007-2008 ACIP and AAP will recommend these children receive TWO doses the second vaccination year

    MMWR 2007;56 (RR-6)

  • The Priming Effect1st dose primes the immune system2nd dose generates specific antibody responseIdeal if first dose given in the fallLess ideal if first dose given in Spring, especially if a new B strain the following Autumn

  • Second Vaccination SeasonDoses in 1st season12Doses this Season21

  • Mix and MatchIf two doses are indicatedNone are contraindicatedCan mix and match TIV/LAIVUse interval of vaccine given first

  • The Magic of Ninth BirthdayOn or after ninth birthday Priming effect caused by natural infection thought to be significant.Only one dose per season required Regardless of previous doses.

  • Inactivated Influenza VaccineContraindications and PrecautionsContraindicationsSevere allergic reaction to a vaccine component (e.g., egg) or following a prior dose of vaccine PrecautionModerate or severe acute illnessHistory of Guillain-Barre within 6 weeks of prior dose

  • Egg allergyPersons with a history of egg allergy who have experienced only hives after exposure to egg should receive influenza vaccine, with the following additional safety measures: a) TIV rather than LAIV should be used. b) Vaccine should be administered by a health-care provider who is familiar with the potent


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