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Disease Prevalence Data for Risk Assessment Presented by: Lou Gallagher, PhD FDA/CBER/OBE Risk Assessment Group

Prevalence of disease in donors is the biggest driver of transfusion-transmitted risk estimates Probability of donor having asymptomatic, transfusion-transmissible disease What we want Why we want it

Information Sources used in FDA Risk Assessments DonorsCollection and Handling Product Distribution and Recipients Donor travel patterns Donor exposure Donor characteristics Source population for donors Screening procedures Screening efficacy Donation volume Donor deferral patterns Recipient characteristics Product availability Probability of disease transmission for infective units Therapeutic doses

Levels of data certainty National disease incidence, passive surveillance Subpopulation disease incidence or prevalence Transfusion-transmitted infections among recipients of blood/blood products Donor subpopulation disease prevalence National donor population disease prevalence Less Certainty More Certainty Probability of donor having asymptomatic, transfusion transmissible disease

Levels of data certainty Incident Babesiosis cases reported by state: CDC and 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: /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: Less Certainty 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 Predicted number of infective units Exposure factors lack specificity, may lack sensitivity Passive surveillance is an underestimate Population vs donors Timeliness }

Information sources used in T. cruzi risk assessment Donors Collection and Handling Product Distribution and Recipients Donor travel patterns Source population for donors Screening procedures Screening efficacy Donation volume Donor deferral patterns Recipient characteristics Product availability Therapeutic doses Published Papers

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

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