Influenza Virus Overview
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Influenza Virus Overview

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Questions and Answers

What type of influenza virus is known for infecting multiple species, including humans, swine, equines, and birds?

  • Influenza A (correct)
  • Influenza B
  • Influenza C
  • Influenza D

    • Which surface protein is primarily associated with the virion envelope of influenza?

  • Nucleoprotein
  • Fusion protein
  • Glycoprotein
  • Hemagglutinin (HA) (correct)

    • Which of the following describes the process of antigenic DRIFT?

  • Sudden mutations due to environmental stress
  • Major changes in HA or NA resulting in novel subtypes
  • Gradual amino acid substitutions causing smaller outbreaks (correct)
  • Complete genetic reassortment between viruses

    • Which vaccine formulation is recommended for a quadrivalent influenza vaccine that is also egg-free?

    <p>Recombinant inactivated vaccine (RIV)</p> Signup and view all the answers

    Which population is specifically contraindicated for the use of the Live Attenuated Influenza Vaccine (LAIV)?

    <p>Pregnant patients</p> Signup and view all the answers

    What is the primary cause of antigenic variation in influenza viruses?

    <p>Changes in HA or NA surface proteins</p> Signup and view all the answers

    What differentiates antigenic SHIFT from antigenic DRIFT in influenza viruses?

    <p>SHIFT creates widespread pandemics; DRIFT results in localized outbreaks</p> Signup and view all the answers

    What type of influenza virus primarily causes major pandemics due to its susceptibility to antigenic variation?

    <p>Influenza A</p> Signup and view all the answers

    Which groups are considered at high risk for influenza complications, warranting specific vaccination recommendations?

    <p>Patients with severe immune deficiency, including those post-transplant</p> Signup and view all the answers

    What is the recommended timing for initiating antiviral treatment for influenza to ensure maximum clinical benefit?

    <p>Within 24 hours of symptom onset</p> Signup and view all the answers

    Which antiviral drug is NOT classified as a neuraminidase inhibitor (NA inhibitor)?

    <p>Baloxavir</p> Signup and view all the answers

    What is the minimum age at which annual influenza vaccination is recommended?

    <p>6 months</p> Signup and view all the answers

    Which of the following scenarios warrants the use of pre-exposure chemoprophylaxis for influenza?

    <p>Individuals with severe immune deficiency unable to receive vaccination</p> Signup and view all the answers

    Which factors contribute to a child aged 2-4 years being considered for increased influenza risk?

    <p>History of asthma or wheezing within the past 12 months</p> Signup and view all the answers

    In the clinical prediction rule for diagnosing influenza, how many points are assigned for myalgias?

    <p>2 points</p> Signup and view all the answers

    Which method is preferred for the prevention of influenza in general?

    <p>Vaccination</p> Signup and view all the answers

    What is the recommended interval for giving the inactivated influenza vaccine to children aged 6 months to 8 years?

    <p>4 weeks apart</p> Signup and view all the answers

    Is routine widespread chemoprophylaxis with antivirals recommended outside of institutional outbreaks?

    <p>No, it is not recommended</p> Signup and view all the answers

    Which symptom combination yields the highest points in the clinical prediction rule for diagnosing influenza?

    <p>Fever and cough, myalgias</p> Signup and view all the answers

    What is the maximum time frame within which antiviral treatment should ideally be initiated for influenza to ensure clinical benefit?

    <p>24 hours after symptom onset</p> Signup and view all the answers

    Which antiviral drug is categorized as a Cap dependent endonuclear inhibitor?

    <p>Baloxavir</p> Signup and view all the answers

    What should be the approach towards chemoprophylaxis with NA inhibitors for patients?

    <p>Recommended for specific high-risk populations only</p> Signup and view all the answers

    Which of the following populations is NOT indicated for post-exposure chemoprophylaxis?

    <p>Individuals recently vaccinated against influenza</p> Signup and view all the answers

    Which treatment is preferred for influenza in pregnant women?

    <p>Oral Oseltamivir</p> Signup and view all the answers

    For children aged 6 months to 8 years, how many doses of inactivated influenza vaccine are recommended?

    <p>2 doses at least 4 weeks apart</p> Signup and view all the answers

    Which of the following statements about routine widespread chemoprophylaxis for antiviral drugs is accurate?

    <p>Not recommended outside of institutional outbreaks</p> Signup and view all the answers

    What type of influenza virus is most associated with significant changes that create novel subtypes capable of causing widespread pandemics?

    <p>Influenza A</p> Signup and view all the answers

    Who among the following is considered eligible for pre-exposure chemoprophylaxis?

    <p>Patients who cannot receive vaccinations</p> Signup and view all the answers

    Which age group is advised to receive annual influenza vaccination?

    <p>Children 6 months and older</p> Signup and view all the answers

    What are the two mechanisms of antigenic variation in influenza viruses?

    <p>Antigenic drift and antigenic shift</p> Signup and view all the answers

    Which protein on the surface of the influenza virion envelope is primarily responsible for facilitating viral entry into host cells?

    <p>Hemagglutinin</p> Signup and view all the answers

    Which statement accurately describes antigenic drift in influenza viruses?

    <p>It causes gradual amino acid substitutions.</p> Signup and view all the answers

    In which type of population is the Live Attenuated Influenza Vaccine (LAIV) contraindicated?

    <p>Pregnant individuals</p> Signup and view all the answers

    Which influenza vaccine formulation is suitable for individuals who require an egg-free option?

    <p>Recombinant inactivated vaccine (RIV)</p> Signup and view all the answers

    What is the recommended strategy for influenza vaccination for healthy individuals over six months of age?

    <p>Annual vaccination for all without contraindications</p> Signup and view all the answers

    What characterizes antigenic shift in the context of influenza viruses?

    <p>Sudden and significant mutations creating new subtypes</p> Signup and view all the answers

    Study Notes

    Influenza Overview

    • Influenza viruses are RNA viruses belonging to the Orthomyxoviridae family.
    • Three types infect humans: Influenza A, B, and C.
    • Influenza A has the broadest host range, infecting humans, swine, equines, and birds.

    Antigenic Variation

    • Antigenic variation in influenza arises from changes in hemagglutinin (HA) and neuraminidase (NA) surface proteins.
    • Two types of antigenic variation:
      • Antigenic Drift: Small, gradual amino acid changes leading to minor outbreaks.
      • Antigenic Shift: Major changes resulting in novel subtypes that can cause pandemics.

    Vaccination Recommendations

    • Annual influenza vaccination is advised for everyone aged six months and older without contraindications.
    • Vaccination options include:
      • Inactivated Influenza Vaccines (IIV)
      • Recombinant Inactivated Vaccine (RIV)
      • Live Attenuated Influenza Vaccine (LAIV), contraindicated in pregnant individuals and specific high-risk populations.
    • Quadrivalent vaccines are egg-free.

    Vaccine Administration

    • IIV preferred over LAIV for vaccination.
    • Children aged 6 months to 8 years need two doses of IIV, spaced at least four weeks apart.

    Clinical Prediction and Treatment

    • A symptom-based clinical prediction rule assists in diagnosing influenza with point assignments for fever, cough, myalgias, and early symptom onset.
    • Antiviral treatments are effective if initiated within 24 hours of symptom onset.
    • Approved antiviral drugs include:
      • Oseltamivir (NA inhibitor)
      • Zanamivir (NA inhibitor)
      • Peramivir (NA inhibitor)
      • Baloxavir (Cap-dependent endonuclease inhibitor)

    Chemoprophylaxis Guidelines

    • Chemoprophylaxis with NA inhibitors is not universally recommended, only for specific high-risk populations.
    • Pre-exposure prophylaxis is suitable for individuals with immune deficiencies or those in close contact with at-risk populations.
    • Post-exposure prophylaxis should be initiated within 48 hours of exposure to influenza, especially for unvaccinated high-risk individuals.

    Preferred Treatment and Prevention

    • Vaccination remains the primary method for preventing influenza.
    • Oral Oseltamivir is the preferred treatment for influenza during pregnancy.
    • Antivirals should not be used for routine chemoprophylaxis outside of outbreaks.

    Influenza Overview

    • Influenza viruses are RNA viruses belonging to the Orthomyxoviridae family.
    • Three types infect humans: Influenza A, B, and C.
    • Influenza A has the broadest host range, infecting humans, swine, equines, and birds.

    Antigenic Variation

    • Antigenic variation in influenza arises from changes in hemagglutinin (HA) and neuraminidase (NA) surface proteins.
    • Two types of antigenic variation:
      • Antigenic Drift: Small, gradual amino acid changes leading to minor outbreaks.
      • Antigenic Shift: Major changes resulting in novel subtypes that can cause pandemics.

    Vaccination Recommendations

    • Annual influenza vaccination is advised for everyone aged six months and older without contraindications.
    • Vaccination options include:
      • Inactivated Influenza Vaccines (IIV)
      • Recombinant Inactivated Vaccine (RIV)
      • Live Attenuated Influenza Vaccine (LAIV), contraindicated in pregnant individuals and specific high-risk populations.
    • Quadrivalent vaccines are egg-free.

    Vaccine Administration

    • IIV preferred over LAIV for vaccination.
    • Children aged 6 months to 8 years need two doses of IIV, spaced at least four weeks apart.

    Clinical Prediction and Treatment

    • A symptom-based clinical prediction rule assists in diagnosing influenza with point assignments for fever, cough, myalgias, and early symptom onset.
    • Antiviral treatments are effective if initiated within 24 hours of symptom onset.
    • Approved antiviral drugs include:
      • Oseltamivir (NA inhibitor)
      • Zanamivir (NA inhibitor)
      • Peramivir (NA inhibitor)
      • Baloxavir (Cap-dependent endonuclease inhibitor)

    Chemoprophylaxis Guidelines

    • Chemoprophylaxis with NA inhibitors is not universally recommended, only for specific high-risk populations.
    • Pre-exposure prophylaxis is suitable for individuals with immune deficiencies or those in close contact with at-risk populations.
    • Post-exposure prophylaxis should be initiated within 48 hours of exposure to influenza, especially for unvaccinated high-risk individuals.

    Preferred Treatment and Prevention

    • Vaccination remains the primary method for preventing influenza.
    • Oral Oseltamivir is the preferred treatment for influenza during pregnancy.
    • Antivirals should not be used for routine chemoprophylaxis outside of outbreaks.

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    Description

    Test your knowledge on the influenza virus with this quiz. Explore its classification, types, and features, including the family it belongs to and its potential for pandemics. Challenge yourself to understand the unique characteristics of influenza A, B, and C viruses.

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