UMEM Educational Pearls

How does it present?

  • Fever, cough, sore throat, runny nose, muscle aches, headaches, fatigue, diarrhea (in children especially)

Who cares…I got my vaccine! Does the vaccine work this year?

  • There has been some antigenic drift this year in the influenza A (H3N2) type virus.
  • 52% are anti-genically different than the H3N2 vaccine virus.
  • So the vaccine is less effective this year but it can give some cross-protection (in addition to protection against the other strains used in the vaccine)
  • CDC recommends still getting the vaccine  (http://www.cdc.gov/flu/protect/vaccine/vaccines.htm)
  • 91% of samples reported to the CDC have been influenza A this year

Can I test for this?

  • Rapid influenza diagnostic tests check for antigen detection
  • Pooled sensitivity of 62%; specificity of 98%
  • False negatives are common
  • Good technique during sample collection is important

The CDC is recommending treatment...wait I thought we were done with Tamiflu?

  • Benefits: shortens the duration of symptoms (day or less), reduces the risk of complications, reduces the risk of death among hospitalized patients
  • Risks: side effects (see below)
  • A recent Cochrane review revealed that treatment did not really help reduce complications and most of the data on anti-viral agents is biased (Roche funded) and hotly debated

Who is at risk/who deserves consideration for treatment?

  • Hospitalized patients with influenza 
  • Old people (>65)
  • Children
  • Pregnant women
  • Chronic medical conditions (asthma, COPD, diabetes, or heart disease)
  • American Indians and Alaskan natives
  • Chronic immunosuppression
  • Institutional outbreaks (nursing homes, correctional facilities)

Pearls of treatment

  • Treat as early as possible (<48hours from symptom onset)
  • 5 days of treatment; twice daily dosing. Wt based for children. Renally dosed.
  • Oseltamivir: used for more severe influenza cases
  • Zanamivir: 7 years or older; IV Zanamivir is currently in Phase III clinical trials

What are the side effects of anti-viral agents?

  • Don’t use zanamivir in patients w/ pulmonary disease
  • Transient neuropsychiatric events for oseltamivir
  • Nausea, vomiting, diarrhea are common both both

 

References

http://www.cdc.gov/flu/index.htm

 2014 Apr 10;4:CD008965. doi: 10.1002/14651858.CD008965.pub4.

Neuraminidase inhibitors for preventing and treating influenza in healthy adults and children.

Jefferson T1Jones MADoshi P, et al.