Gallagher Disease Prevalence Data for

							Disease Prevalence Data for
     Risk Assessment
             Presented by:
           Lou Gallagher, PhD
   FDA/CBER/OBE Risk Assessment Group
     Probability of donor having
asymptomatic, transfusion-transmissible
                disease


  What we want

                                  Why we want it


        Prevalence of disease in donors is the
       biggest driver of transfusion-transmitted
                    risk estimates
   Information Sources used in FDA
          Risk Assessments
       Donors               Collection and          Product Distribution
                              Handling                and Recipients


Donor travel patterns   Screening procedures      Recipient
Donor exposure          Screening efficacy        characteristics
Donor characteristics   Donation volume           Product availability
Source population for   Donor deferral patterns   Probability of disease
donors                                            transmission for
                                                  infective units
                                                  Therapeutic doses
         Levels of data certainty
                 • National disease incidence, passive
Less Certainty
                   surveillance
                 • Subpopulation disease incidence or
                   prevalence
                 • Transfusion-transmitted infections among
                   recipients of blood/blood products
                 • Donor subpopulation disease prevalence
                 • National donor population disease
                   prevalence
More Certainty
                   Probability of donor having asymptomatic, transfusion
                                    transmissible disease
         Levels of data certainty
                 • Incident Babesiosis cases reported by state:                                 CDC and
Less Certainty      Public Health Agencies


                 • Population prevalence from opportunistic tissue
                   samples in affected area: Prevalence of disease related prion
                    protein in anonymous tonsil specimens in Britain: cross sectional opportunistic
                    survey BMJ 2009;338:b1442 doi:10.1136/bmj.b1442


                 • Population incidence from official health
                   department statistics in affected area: DIRECCIÓN
                    GENERAL ADJUNTA DE EPIDEMIOLOGÍA, Mexico (Malaria)


                 • Population seroprevalence from affected area: West
                    Nile Virus in Queens, New York. Epidemic West Nile encephalitis, New York, 1999:
                    results of a household-based seroepidemiological survey. Lancet 2001;358:261-4.


More Certainty
                     Probability of donor having asymptomatic, transfusion
                                      transmissible disease
         Probability of donor having
    asymptomatic, transfusion-transmissible
                    disease

Surrogate measures can introduce bias, measurement error and false
confidence


Exposure factors lack specificity,
may lack sensitivity                             Predicted number



                                     }
                                                 of infective units
Passive surveillance is an
underestimate
Population vs donors
Timeliness
         Information sources used in
           T. cruzi risk assessment
       Donors              Collection and           Product Distribution
                             Handling                 and Recipients

Donor travel patterns   Screening procedures      Recipient
Source population for   Screening efficacy        characteristics
donors                  Donation volume           Product availability
                        Donor deferral patterns   Therapeutic doses



Published Papers

                                                  Published Papers
         Information sources used in
           Babesia risk assessment
                            Collection and          Product Distribution
       Donors
                              Handling                and Recipients

Donor travel patterns   Screening procedures      Probability of disease
Source population for   Screening efficacy        transmission for
donors                  Donor deferral patterns   infective units
                                                  Therapeutic doses
         Information sources used in
           Malaria risk assessment
       Donors              Collection and       Product Distribution
                             Handling             and Recipients

Donor travel patterns   Screening procedures   Probability of disease
Source population for   Screening efficacy     transmission for
donors                                         infective units
                                               Therapeutic doses
          Common Goals
• Medical and Public Health
  Preparedness, HHS
• FDA
• CDC
• NIH
• Blood Collection Agencies
• Consumer Safety Advocates
• Therapeutics Industry
                Risk Assessment Data
What does CBER want?
• Donor prevalence data for asymptomatic
  infection
Survival of agents in processing and infectivity of new agents in naïve recipients are also
   critically important but are not being addressed in this workshop

• Early warning systems (global viral
  forecasting?)
• Research partnerships
• Collaborative data generation using new
  methodologies