Malaria screening of donors and donations - issues and outcomes

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1 Malaria screening of donors and donations - issues and outcomes lan Kitchen National Transfusion Microbiology NHS Blood & Transplant London IPF/PEI, Rome, May 2014 Blood and Transplant

2 Key elements Nature of the problem? Defining malaria risk Dealing with the risk Screening & outcomes Confirmation & outcomes

3 Nature of the problem? Malaria is a serious disease with significant morbidity and mortality currently five spp. known to infect humans Plasmodium falciparum, vivax, ovale, malariae, knowlesi Transmission via blood/products into a malaria naïve individual is likely to result in infection Transfusion transmitted malaria is serious and may be fatal 3/5 identified cases in England were fatal Malaria is a significant transfusion risk in many non-endemic countries, but it can be dealt with effectively

4 Nature of the problem Non-endemic countries face the risk of malaria transmission through donations from donors who have been exposed to malaria Limited options: defer or screen Whatever approach is taken, malaria risk has to be defined, including deferral periods

5 changing situation Changing donor populations require changing strategies Changing donation types require changing strategies Malarial b screening of donations from risk donors is effective in minimising risk

6 Defining malaria risk ny donor who has been exposed to malaria previous residents (those born in and/or lived in endemic areas for at least 6/12) travellers to endemic areas (for a defined period after last return) donors with a history of diagnosed malaria Of these, those with a residency risk are arguably the group with the highest risk, due to semi-immunity semi-immunity is presence of persistent low level parasitaemia with high titre b (expected in donors from endemic countries with high EIR)

7 Dealing with the risk Ignore - do nothing no donors with malaria risk; not an option within the EU Defer permanent/temporary If temporary, for how long? llow donation and screen for malarial b, releasing to inventory if malarial b negative: at least 4-6/12 after their last return from an endemic area at least 3 years after cessation of treatment/symptoms Travellers may donate without b screening after 12/12 since last return from a malarious area

8 The extent of the issue Significant number of NHSBT donors with malaria risk England has very broad range of nationalities Migrants bring in the diseases present in their home countries, a significant proportion come from malaria endemic countries Migrant populations both volunteer blood donation and are specifically targeted to match blood and tissue types to recipient populations UK born donors travel NHSBT malarial b screening figures Year No. screened (Q1) 5887

9 Screening options The sensitivity/appropriateness of the individual potential screening targets, in the context of donation screening, is the issue Parasite malarial DN malarial g insufficient sensitivity in this context (very low infectious dose ) Immune response malarial b with appropriate length deferral (to allow b to appear) is an appropriate strategy

10 Screening Within NHSBT all donations from malaria risk donors screened for malarial b at least 6/12 after their last return from an endemic area approximately 97% overall screen negative approximately 3% overall screen reactive NHSBT donor risk breakdown: 21% Residency 77% Travel 2% History of malaria

11 Screen reactive breakdown by region Screen reactive malaria risk donors by risk & region: frica, Indian sub-continent, Other (Gulf, sia, S. merica) Residency 32% frica, 65% India, 3% Other Travel 25% frica, 57% India, 18% Other Had malaria 67% frica, 29% India, 4% Other

12 Confirmation of screen reactivity REMEMBER - all donors screened have a defined malaria risk Performed to try to determine in which of the screen reactive donations the reactivity is specific assumed to have been infected at some time Previous transmissions in England have demonstrated that there are donors who are still parasitaemic identification of parasitaemic donors was deemed important as these individuals need clinical review identification of such individuals helps define and refine malaria risk and screening policy and strategy

13 Confirmation of screen reactivity 2 additional microplate immunoassays (Cellabs & DiaPro) Immunofluorescent b using cultured falciparum infected human red cells Donors with reactivity in any of the above assays look for malarial DN using a pair of assays that detect ssrrn gene sequence, but where falciparum has a small but stable sequence difference to vivax, ovale, malariae and knowlesi

14 Confirmatory outcomes Breakdown of malaria risk in donors Donations Referred for Risk screened confirmation Residency 21% 63% Travel 77% 17% Had malaria 2% 20% Overall breakdown of confirmatory outcomes: 36% positive (approx 0.95% of donations screened) 23% inconclusive 41% negative 16 malarial DN positives (0.6% of screen reactives)

15 Malaria DN positive donors Case Lab Conf. Diapro Cellabs IFT No. 21 DN Comments 1 Pos Pos Pos 1/640 Pf Male, dob 05/03/91, from Nigeria, came to UK in Sept Pos Neg Pos 1/640 Pf Male, dob 26/09/76, from Ivory Coast, came to UK in Pos Pos Pos Neg Pv Male, dob 18/02/89, from India, came to UK in Pos Pos Neg 1/80 Po Male, dob 17/03/67, from Nigeria, came to UK in Pos Pos Pos Neg Pv Male, dob 19/12/88, student from India, came to UK in Oct Pos Neg Pos 1/160 Po Female, dob 09/10/90, from Nigeria, came to UK 2008, malaria aged 16 7 Pos Neg Pos 1/640 Pf/Pm Male, dob 01/6/82, from Ghana, came to UK in Revisit in Pos Pos Pos Neg Pv Male, dob 11/11/91, from Pakistan, came UK in Feb Pos Pos Pos 1/640 Pf Female, dob 11/10/81, from Nigeria, came to UK in Pos Neg Pos Neg Po Male, dob 03/06/86, from South frica, came to UK in Malaria when aged 6 11 Pos Neg Pos 1/640 Pm Male, dob 01/09/81, Born in Nigeria, came to UK in Pos Neg Pos 1/320 Pm Male, black frican, born in Nigeria 22/09/77. UK in 2004, last visit endemic area Pos Pos Pos Neg Pv Male, dob 23/9/87, born India, lived in frica, Dubai. Came to UK Subsequently declared diagnosed with malaria in June Pos Pos Pos Neg X Male, dob 28/10/1980, born India, last return Jan Donor admitted to malaria in India in 2011 but was treated at the time. 15 Pos Pos Pos Neg Pv Male, dob 24/09/91, born Pakistan, came to UK in May Pos Pos Pos 1/640 Pf Male, dob 10/01/77. Born Sierra Leone, came to UK Cerebral malaria 2008, treated Kingston Hospital. Visit to

16 Case No. Lab21 ratio Malarial DN positives serology results Diapro ratios Cellabs ratios Diamed ratios Novatec ratios Conf. DN IFT / / / /640 Pf / / / /640 Pf / /14.4 ND /640 Pf / /15.71 ND ND 1/640 Pf / / / /640 Pf/Pm / / / Neg Pv / /12.8 4/ Neg Pv / / / Neg Pv / /9.32 ND ND Neg Pv / /4.98 ND ND Neg Pv / /3.52 ND ND Neg X / / / /80 Po / / / /160 Po / /2.04 ND 0.54 Neg Po / /13.8 ND /640 Pm Blood 12 and Transplant / /8.41 ND 0.77 IPF/PEI, 1/320 Rome, May 2014 Pm

17 Risk group Malaria - resident Malaria traveller Resident Traveller Final result Pos Incon Neg Early analysis of serology results v. risk Lab21/Trinity (screen) Cellabs (Ref) DiaPro (Ref) No. IFT % by region I O I O I O positive I O Pos Incon Neg Pos Incon Neg Pos Incon Neg Too few Too few Too few Too few /63 () 2/32 (I) Too few 2/25 () Too few /102 () 6/187 (I) /12 () 1/24 (I) 2/7 () 1/3 (O)

18 Is screening effective? With the correct deferral guidelines Yes since updating guidelines no reported cases in England no reported cases in ustralia from Occasional breakthrough cases, but the number of safe donations released should be the focus cases in France in 2002, 2006, 2012 In US, deferral but no screening, there have been 7 cases of TTM reported between ll reported cases, including previous English cases, involved donors who had lived in frica

19 In conclusion Identifying malaria risk in donors of blood and other products is essential Malarial antibody screening of at risk donors/donations is effective the majority (>95%) of donations are screen negative Parasitaemic donors are being identified, even after some years since last in an endemic area donations from these donors will transmit malaria strategies need to take account of this More detailed analysis of serology data against donor risk may help: understand the specificity of the reactivity improve the specificity and predictiveness of confirmation influence/improve malaria screening strategies

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