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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. Existing surveillance programs (overview) Data available for evaluation of VE Navy VE estimate (recruit centers)
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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
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) Topics to be Covered
2000-2001 Collaborating Sites Existing Surveillance Programs-AF • AF Program (AFIOH) • 27 sentinel sites • Clinical and convenience sampling • 1O objective: isolates
Great Lakes Cape May Ft Leonard Wood Ft Bragg Ft Jackson MCRDSan Diego MCRD Parris Island Lackland AFB 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
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
ILI Activity Data Sources • Local public health officer reports
Data Sources (cont’d) • Local public health officer reports • Coded ambulatory visits • ESSENCE • “DNBI”
Data Sources (cont’d) • Local public health officer reports • Coded ambulatory visits • ESSENCE • “DNBI” • Laboratory results • Surges from a site • Unusual results
Data Sources (cont’d) 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
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
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% VE calculation
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
Ft. Lee ILI Epi Curve Mass Immunizations CHPPM/WRAIR EPICON
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
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? AF IVE Evaluation: Plan A # specimens=2459 # positive = 859 # eligible = 114 Total # of family members=400
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 AF IVE Evaluation: Plan B
NHRC: VE = 91% CHPPM: VE = 40-100% AF: VE = pending Many details . . . Summary
Questions Contact information: Col James Neville, MD, MPH E-mail: james.neville@brooks.af.mil Phone: 210-536-2002