# Presentation: 749489

## Workshop SummaryFDA Workshop on Testing for malarial Infections in Blood Donors

- Sanjai Kumar, Ph.D.
- Center for Biologics Evaluation and Research
- Food and Drug Administration
- Blood Products Advisory Committee Meeting
- July 13, 2006

## Issue

** ****FDA seeks public discussion of scientific developments that might support donor testing for malarial infections as part of pre-donation testing or as follow-up testing to permit a reduced deferral period for donors deferred for risk of malaria.**

## Topics for Question

-  **Malaria in the USA and the main sources of malaria risk to the blood supply**
** ****Risks and benefits of screening donors for malaria infections in lieu of risk-based deferrals**
** ****Available and emerging technologies to test blood donors for malarial infections**
** ****Potential effects of  donor testing for malarial infections on the safety and availability of the blood supply under the following scenarios:**
**	****- ****Universal malaria antibody testing of all blood donors**
**	****- ****Testing for donors who are deferred based on a history of possible malaria exposure or had experienced clinical malaria in order to accelerate reentry.**

## Background. Antibody testing in Europe and Australia 

-  **Several European countries and Australia now test deferred at-malaria-risk donors by an EIA that detects antibodies to P. falciparum and P. vivax**
** ****In UK, individuals who had malaria or a history of prior residence in endemic countries are deferred indefinitely, all other prospective donors are deferred for one year after each return**
** ****At-risk donors having no antibodies by EIA at least six months after the last potential exposure or symptom of malaria are allowed to renter**
** ****In France, travelers are allowed to donate if found negative for malarial antibody at least four months after return**

## Slide 5

## Slide 6

## Session I: Malaria in USA (Parise, CDC) 

-  **Travel to Africa accounts for only 0.6% of US travel in 2003, yet, 66.2% of all malaria infections and 85.9% of all *****P. falciparum***** infections were acquired in Africa in 2003**
** ****From 1985-2002, 93% of all malaria deaths in US travelers due to Pf - 73% of those were acquired in sub-Saharan Africa**
** ****TTM in US since (1990-2005)**
**	****16 cases; 1 US traveler (Kenya), 1 VFR (Africa), 12- immigrants, 12/14 acquired in Africa, 71% Pf**

## Slide 8

## Session II Testing for Malaria Infections (Nigel Appleton, Newmarket  Labs)

-  EIA sensitivity: Pf: 94%; Pv: 100%. Cross-reactive: Pm: 80%; Po: 67%
-  EIA new version:
- 	1 antigen		Sensitivity 	69%
- 	2 antigen		Sensitivity 	73%
- 	3 antigen		Sensitivity 	82%
- 	4 antigen		Sensitivity 	99%
- 4 antigens (3 Pf and 1 Pv): 99% sensitivity

## Session II Testing for Malaria Infections (Sanjai Kumar, FDA)

-  **Highly infectious nature of malaria parasites causes a potential risk from a few parasites that could be present in a unit of blood**
** ****Highest sensitivity achieved: 2 to 20 parasites/ml or 1000 parasites in a unit of blood**
** ****Minimum number of infectious parasites present in a unit of blood:  Not known (biggest road block)**
** ****Possible solutions: **
**	****	****- A technology for parasite concentration **
**	****	****- An accurate knowledge of the minimum parasite burden in infected donors would allow to determine the required assay sensitivity**

## Slide 11

## Session III Testing for Malaria Infections in Blood Donors

-  **Prof Chiodini, UK**
**Donor testing for malarial antibodies in at-risk populations**
**2004****	****	****42947 tested****	****1209 RR ****	****	****2.82%**
**2005****	****	****66994****	****	****1368****	****	****	****2.04%**
**J-M 06****	****	****11988****	****	****236****	****	****	****1.97%**
** ****Prof Garraud, France **
**  ****- ****# of donations tested: 75,016 (≈3.5%)**
**Negatives: 97.42%**
**Positives: 1%**
**Indeterminate: 1.59%**

## Session III Testing for Malaria Infections in Blood Donors (Susan Stramer, ARC)

** ****Total malaria deferrals (23, 611, 536 presenting donors)**
**2000-2005 (mean donation rate 1.69)**
**	****	****No.****	****	****%****	****	****Projected total lost donor****	****	****	**
**Travel****	****	****241,777****	****1.01****	****	****410,844**
**Resident****	****25, 339 ****	****1.69****	****	****42, 635**
**Malaria****	****495****	****	****.002****	****	****831**
**Total****	****	****267,611****	****1.13****	****	****454,310**
** ****Australian EIA experience- at risk donors (7/17/05-3/30/06)**
**	****26, 356 donors screened (vistors/residents/infection)**
**	****2.28% RR **

## Session III Testing for Malaria Infections in Blood Donors (David Leiby, ARC)

** ****EIA Newmarket testing of Non-deferred donors**
**	****N ****	****3,229**
**	****1R****	****21 (0.65%)**
**	****RR****	****11 (0.34%)**
**11 RR Donors: 2-no travel; 2-born or lived in Africa; 1 travel to India; 4-previously dx/tx for malaria > 3 years ago, at least 3 lived/born in Africa**
**Confirmatory testing: CDC  **

## Slide 15

## Session IV

** ****Donor deferral: Majority of clinical infections and TTM from donors born or lived in Africa. Doubts about 1 year deferral policy for all travelers especially those going to resorts in Mexico**
** ****Parasite detection-**
**	****-****DNA based tests:**** ****Technology deemed not ready due to its inability to detect a few parasites in a unit of blood**
**	****-Antibody testing: Experiences in UK, France and Australia were found to be satisfactory based on detection of 2/4 species**
**	**

## Session IV

** ****Antibody testing in the US-**
**	****- Universal testing: Mixed responses but issue should remain open especially if there is sudden surge in malaria infections in the US**
**	****- Testing in at-risk populations: More data needed for geography based distribution and species prevalence to decide the number of species representation in the assay**
**	****- Some members of blood banking industry expressed concern regarding logistics related to database configuration to accommodate donor testing in a selected population**
**	**