DoD Influenza Surveillance for VRBPAC

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Estimating Influenza Vaccine Effectiveness in the
DoD
Col James Neville, MD, MPH Deputy
Director 210-536-2002
Sustaining Readiness through Healthy Communities
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Topics to be Covered

• Existing surveillance programs (overview)
• Data available for evaluation of VE
• Navy VE estimate (recruit centers)
• Army VE estimate (Ft. Lee outbreak)
• AF VE estimate (phone survey, underway)

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Existing Surveillance Programs-AF

• AF Program (AFIOH)
• 27 sentinel sites
• Clinical and convenience sampling
• 1O objective isolates

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Existing Surveillance Programs-Navy

• AF Program (AFIOH)
• 27 sentinel sites
• Clinical and convenience sampling
• 1O objective isolates
• Navy Program (NHRC)
• Military Training Centers
• Convenience sampling
• Objective ILI rates, isolates

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Existing Surveillance Programs-Army

• AF Program (AFIOH)
• 27 sentinel sites
• Clinical and convenience sampling
• 1O objective isolates
• Navy Program (NHRC)
• Military Training Centers
• Convenience sampling
• Objective ILI rates, isolates
• Army Program
• MEDCENs, clinical virology labs
• Special studies

- Army MEDCEN
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ILI Activity Data Sources
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ILI Activity Data Sources

• Local public health officer reports

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Data Sources (contd)

• Local public health officer reports
• Coded ambulatory visits
• ESSENCE
• DNBI

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Data Sources (contd)

• Local public health officer reports
• Coded ambulatory visits
• ESSENCE
• DNBI
• Laboratory results
• Surges from a site
• Unusual results

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Data Sources (contd)
Cumulative AF Influenza Vaccination

• Local public health officer reports
• Coded ambulatory
• ESSENCE
• DNBI
• Laboratory results
• Surges from a site
• Unusual results
• Immunization data
• Individual level

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NHRC VE Data

• Existing data from surveillance program
• Trainees at 4 training bases
• December 2003
• Influenza culture positives only
• Person-time analysis
• Weeks at risk
• Vaccinated vs. unvaccinated (2 wks post vax)
• Basic trainees are vaccinated upon arrival

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NHRC data (contd)
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VE calculation

• AR vax 4 cases / 54278 person-wks
• 7.37/100,000 person-wks
• AR unvax 15 cases / 18617 person-wks
• 80.6/100,000 person-wks
• RR 7.37 / 80.6 0.0914
• VE 1 RR 90.9

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Ft Lee, Virginia

• US Army post - Quartermaster Training
• 3,200 trainees courses of varying length
  12/week turnover
• Influenza outbreak, 31 Oct-11 Nov 2003

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Ft. Lee ILI Epi Curve
Mass Immunizations
CHPPM/WRAIR EPICON
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Ft Lee, Virginia

• US Army post - Quartermaster Training
• 3,200 trainees courses of varying length
  12/week turnover
• Influenza outbreak, 31 Oct-11 Nov 2003
• PH response mass immunization, case isolation
• Vaccine Effectiveness Study Attempt
• 2 cohorts
• tight and loose case definition
• Limitations temporality, highly immunized
  population, exhaustion of susceptibles, random
  mixing assumption

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VE Results
loose case def. tight case def.
Cohort A arrival date 10 Nov 03 (n267) 40.5 -48, 76 (26 cases) 51.2 -357, 78.1 (5 cases)
Cohort B arrival date 1724 Nov 03 (n463) 60.2 -167, 86.4 (15 cases) 100 no CI by method used (4 cases)
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AF IVE Evaluation Plan A
specimens2459
positive 859

• Identify exposed cohort (AF only, not Academy)
• Index cases influenza culture positive in AFIOH
  lab
• Contact sponsor for household health histories
• Influenza vaccinations
• Febrile respiratory illnesses within 2 wks of
  index case
• Calculate secondary attack rate
• Compare vaccinated and unvaccinated
• IRB approved telephone surveys began 2 Feb 2004
• results pending
• Annual routine study?

eligible 114
Total of family members400
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AF IVE Evaluation Plan B

• Identify site with ongoing transmission
• Lab submissions, ESSENCE, other reports
• Index cases influenza culture positive in AFIOH
  lab
• Decision Launch on-site investigation vs.
  telephone only
• Surveillance data sources to assess extent of
  local outbreak
• Contact sponsor/parent directly for household
  health histories
• Influenza vaccination history
• Febrile respiratory illness within 2 wks of index
  case
• Validate data with medical records, vaccination
  registry, labs
• Use secondary attack rates to estimate VE
• Annual routine study?
• Pending IRB AF approval

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Summary

• NHRC VE 91
• CHPPM VE 40-100
• AF VE pending
• Many details . . .

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Questions
Contact information Col James Neville, MD,
MPH E-mail james.neville_at_brooks.af.mil Phone
210-536-2002
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Back-ups
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Specimen Results by Week of Training
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AF Lab Results
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AF Lab Results