H1N1 SOIV

1

The Flu and You H1N1 in 2009
Robert T. Schooley, MDProfessor of
MedicineUniversity of California San Diego
From RT Schooley, MD, at 12th Annual Ryan White
HIV/AIDS Program Clinical Conference, IASUSA.
2
Percentage of Hospitalized Patients with H1N1 Sw
by Age Group
Percent of Patients in Age Range
Age Range, Years
3
Underlying Conditions in Hospitalized Patients
Jain, NEJM, 2009
4
What Are We Likely to See this Year?
5
Case Rates by Age Group
6
What Can We Do to Limit Morbidity and Mortality?

• Diagnose
• Prevent
• Treat
• Vaccinate

7
Diagnosis

• Culture
• Grows of MDCK or monkey kidney cells
• Sensitive but takes several days
• Rapid tests
• Several available that detect Influenza A antigen
  developed with seasonal H1N1 antigen so only 35
  60 sensitive for H1N1 Sw
• PCR
• New gold standard. Rapid but must be done in
  reference laboratory

8
Prevention

• Not possible to prevent infection in general
  population by quarantine or other draconian
  measures it is already here
• Focus areas
• Healthcare settings
• Institutional settings
• primarily schools
• Military populations

9
Benefits of Therapy are Relatively Modest in
Uncomplicated Influenza
10
Benefits of Therapy are Most Demonstrable Early

• Dont delay therapy for diagnostic tests if the
  patient is at higher risk for complications of
  therapy
• Use in severe disease but dont expect much help

11
Who is At Higher Risk for Complications from H1N1
Sw?

• Children less than 5 years old
• Persons aged 65 years or older
• Children and adolescents (less than 18 years) who
  are receiving long-term aspirin therapy and who
  might be at risk for experiencing Reye syndrome
  after influenza virus infection
• Pregnant women
• Adults and children who have chronic pulmonary,
  cardiovascular, hepatic, hematological,
  neurologic, neuromuscular, or metabolic
  disorders
• Adults and children who have immunosuppression
  (including immunosuppression caused by
  medications or by HIV)
• People with arthritis
• Residents of nursing homes and other chronic-care
  facilities.

12
The Vaccine

• Hemagglutinin differs from previously circulating
  H1N1 strain by 20
• Neuraminidase varies by 70
• Minimal de novo protection from current vaccine
• Demonstrated clearly in Australian experience
• Seasonal influenza vaccinations ready since
  early September
• Initial S-OIV vaccine available now with more to
  come

13
High Priority Groups for H1N1 Vaccination

• pregnant women,
• persons who live with or provide care for infants
  aged lt6 months (e.g., parents, siblings, and
  daycare providers),
• health-care and emergency medical services
  personnel,
• persons aged 6 months--24 years, and
• persons aged 25--64 years who have medical
  conditions that put them at higher risk for
  influenza-related complications.

14
Influenza H1N1 SOIV and HIV Infection

• Currently no evidence that it is more severe in
  HIV-1 infected persons in most cases
• Shedding of virus likely more prolonged
  especially in those with advanced disease
• Vaccine
• No evidence that it is harmful in terms of HIV
  activation
• Less likely to be efficacious in those with low
  CD4 cell counts or high viral loads
• Killed virus vaccine (traditional egg based
  vaccine) rather than inhaled vaccine should be
  used