Influenza Flashcards
What are the antigenic changes of influenza A?
- antigenic drift (minor changes in the viral surface antigens, point mutations in the gene segment, may result in an epidemic)
- antigenic shift (major change in one or both surface antigens, due to exchange of gene materials between influenza viruses, may result in worldwide pandemic)
What is the timeline of symptom onset and viral shedding of influenza?
- incubation period is typically 1-4 days (2 day average)
- viral shedding may occur 12-24 hours before onset of symptoms
- viral shedding peaks at day 2-3
- viral shedding may persist for 5-7 days
What is the clinical presentation of Influenza?
- fever
- dry cough
- sore throat
- rhinorrhea
- nasal congestion
- headache
- myalgias
- fatigue
- vomiting and diarrhea
What patient population is at high risk for severe disease from an influenza infection?
- children aged 6-59 months (highest risk <2 years old)
- adults 50+ years old
- patients with chronic medical conditions
What complications may occur due to an influenza infection?
- bacterial pneumonia
- sinus infections
- acute otitis media
What patients should recieve antiviral treatment for influenza?
- hospitalized patients with confirmed or suspected influenza
- outpatients with confirmed or suspected influenza with severe, complicated, or progressive illness
- pt with higher risk of complications
- children < 2 years old and adults 65+ years old
- pregnant women and those within 2 weeks postpartum
What is the spectrum of action of neuraminidase inhibitors?
influenza A and B
What is the duration of therapy for Zanamirvir?
5 days
What is the duration of therapy of Oseltamivir?
5 days
What is the duration of therapy of Permivir?
1 dose
What is the dosing of Zanamivir?
2 inhalations BID
What are the adverse effects of Zanamivir?
headache, cough, throat discomfort, bronchospasms, sinusitis, dizziness, skin reactions, rare nervous system effects
What is the mechanism of action of neuraminidase inhibitors?
inhibition of neuraminidase enzyme -> preventing the budding of new virus
What drugs are neuraminidase inhibitors?
- zanamivir
- oseltamivir
- peramivir
What is the dosing of Oseltamivir?
one tablet PO BID
What are the adverse effects of Oseltamivir?
headache, cough, throat discomfort, bronchospasms, sinusitis, dizziness, skin reactions, rare nervous system effects
What is the dosing of Peramivir?
1 IV infusion over 15-30 minutes
What are the adverse effects of Peramivir?
diarrhea, skin reactions, rare nervous system effects
What is the mechanism of action of Xofluza (baloxavir marboxil)?
inhibits endonuclease activity of selective polymerase acid (PA) protein -> prevents virus replication
What is the spectrum of action of Xofluza (baloxavir marboxil)?
influenza A & B
What the dosing of Xofluza (baloxavir marboxil)?
single oral tablet dose of 40mg or 80mg based on weight
- 40 kg to < 80 kg= one 40mg dose
- 80+ kg= one 80mg dose
What are special pharmacokinetic considerations of Xofluza (baloxavir marboxil)?
prodrug with a Vd of 1180L (use TBW for dosing)
Which influenza vaccines are non egg based?
ccIIV3 and RIV3
inactivated vaccines (not live attenuated)
At what age can patients begin to obtain influenza vaccines?
6 months
What are the influenza vaccine recommendation for patients 65+ years old?
- high dose inactivated influenza vaccine
- recombinant influenza vaccine (RIV3)
- adjuvanted inactivated influenza vaccine (aIIV3)
When would the live attenuated vaccine (LAIV3) be indicated?
- healthy, non-pregnant age 2-49 years old
- people in contact with high risk groups, healthcare personal
option for individuals with egg allergy
When would the IIV vaccine be indicated?
- age 6+ months
- pregnant women and immunocompromised patients
option for individuals with egg allergy
When would the RIV vaccine be indicated?
- age 18+ years
- pregnant women and immunocompromised patients
option for individuals with egg allergy
When would the ccIIV vaccine be indicated?
- age 6+ months
- pregnant women and immunocompromised patients
option for individuals with egg allergy
What is an important contraindication of live attenuated influenza vaccine (LAIV3)?
antiviral medication use in recent days