OA1-AM24-ST-17 - A Non-Testing Strategy For Protecting The Blood Supply From Mosquito-Borne Infections In Florida

Background/Case Studies: This Florida (FL) blood center (BC) has over one million collections annually and is unique as its
service area has frequent transfusion-transmissible (TT) emerging pathogen outbreaks. Since the BC
formed in 2012, FL has had intermittent autochthonous (AU) cases of mosquito-borne pathogens
including dengue (DEN), chikungunya(CHKV), Zika and in 2023, malaria (MA). In 2013, the BC and the Florida Department of Health (FDOH) collaborated to address AU cases of DEN. The FDOH used aggressive mosquito tracking/control, public
education, targeted additional donor questioning, administration of a questionnaire, plus blood testing of occupants of the affected area, and the BC ceased collections from at-risk regional donors. In 2014, AU CHKV appeared in FL, with 11 cases in 4 counties, along with an outbreak of 6 AU cases of DEN in one county. Lacking screening tests, in 2014-15, the BC developed a non-testing strategy (NTS) to mitigate the risk of transfusion transmission (TT) without significantly impacting the blood supply. The NTS was reported on and reviewed by FDA. In 2016, BC initially used the NTS for an outbreak of Zika, later switching to investigational testing. In 2023, the NTS was modified to apply to MA, an intracellular parasitic disease which differs clinically from the
arboviruses.

Study

Design/Methods:
The NTS (Table 1) is applied when no proven testing is available for the disease. BC response is based on public health reports issued by the FDOH and Centers for Disease Control (CDC). The NTS employs an escalating threat-level response applied to defined areas represented by zip code (ZC) and/or county and adjacent regions. Each level of threat incorporates mitigation measures of the prior level. Since 2014, BC has used the NTS for vector-borne arboviral threats to the FL blood supply. In 2023, the NTS was modified for the non-arboviral threat of MA.

Results/Findings: Since 2014, the use of the NTS for AU vector-borne arbovirus and MA has resulted in no reports of related TT infections or blood product shortages. In 2023, the modified NTS was activated in 8 FL ZCs for 123 days with 70 collections discarded (0.021% of the BC collections for the activation period and0.007% of annual collections), while the NTS was activated for DEN in 56 FL zip codes for 263 days with 294 collections discarded (0.041% of collections for the activation period and 0.03% of annual collections). 96% of discards involved red cells or whole blood. 13% of the total discards were unrelated to the NTS.

Conclusions: Since its initiation in 2014, the NTS combined with FDOH support has proven to be effective in protecting the blood supply from mosquito-borne TT infectious disease threats in FL.