从疫区返回的献血者登革热病毒的延期标准和检测策略调查结果

Deferral criteria and testing strategies fordengue virus in blood donors returning fromaffected areas Survey results Key findings To support discussions with the ECDC network on substances of human origin (SoHO-Net), ECDC conducted asurvey among members of the SoHO-Net blood group on the donor assessment and deferral strategies for blooddonors in the European Union/European Economic Area (EU/EEA) countries with regard to dengue virus. Thisreport presents the results of the survey. •While 91% of the responding EU/EEA countries have deferral criteria for blood donors returning from dengue-endemic areas, only 55% have specific criteria for those returning from affected non-endemic areas within theEU/EEA.•For countries that defer donors returning from endemic countries or affected areas in non-endemic countries,the deferral period is consistently 28 days. For donors with a confirmed dengue diagnosis, the deferral period isreported as 120 days.•Different trigger criteria are used to implement safety measures for prospective donors returning from affectedareas with local dengue outbreaks in EU countries. Five countries implement safety measures when there is atleast one locally-acquired case in an area with an active cluster of dengue, while six countries implementmeasures on a case-by-case basis.•Deferral of prospective donors who have travelled to a dengue affected area is the most commonly used bloodsafety measure for prevention of transfusion-transmitted dengue. Nucleic Acid Testing (NAT) for dengue israrely reported as a screening tool.•There is no standardised definition for the geographical scope of an ‘affected area’ for local dengue outbreaks inEU countries, with risk levels being applied at the country, regional, or municipal level by different Member States. Conclusions: The increasing frequency and size of autochthonous dengue outbreaks in EU/EEA countriespresents an emerging challenge for blood safety. Safety measures reported by EU/EEA countries generallyaddress travellers returning from endemic countries outside the EU and only a few countries report measures fortravellers returning from affected areas in non-endemic countries. Introduction Dengue virus (DENV) is an enveloped, single-stranded, positive RNA virus belonging to theFlaviviridae family,within theFlavivirus genus. There are four distinct serotypes of DENV (DENV-1, DENV-2, DENV-3, and DENV-4),each capable of causing the full spectrum of dengue. The virus is primarily transmitted to humans through thebite of infected femaleAedes mosquitoes, particularlyAedes aegypti andAedes albopictus [1]. In addition to thevectorial route, DENV can also be transmitted through perinatal transmission [2], blood transfusion [3], stem celltransplantation [4], organ transplantation [5], and needlestick injuries [6]. Probable sexual transmission of DENVhas also been documented [7]. The clinical manifestations of dengue range from mild, asymptomatic infections to severe and potentially life-threatening conditions. It is reported that 60–80% of individuals infected with DENV will remain asymptomatic[8]. However, this proportion can vary widely across studies due to the impact of prior infections on thelikelihood of severe dengue, as well as differences in methodological aspects [9]. The definition of‘asymptomatic’ seems to be one key aspect for this variation. In a systematic review of the asymptomaticdengue infection rate, authors reclassified asymptomatic infection into three groups, aiming for a more precisedescription of the cases included: no symptoms, subclinical (i.e. mild or aspecific symptoms), and unapparent(infections not captured by the healthcare system regardless of symptomatology). Rates of asymptomaticinfection ranged from 0 to 42% of cases (median 7.5%, six studies) for the ‘no symptoms’ category; 0 to 100%of cases (median 64%, 30 studies) for the ‘subclinical’ category, and 50 to 100% of cases (median 72%, 14studies) for the ‘unapparent’ category [9]. In symptomatic cases, the incubation period typically lasts four to seven days (range: 3−10 days [10]), after whichpatients may experience a sudden onset of high fever, severe headache, retro-orbital pain, myalgia, arthralgia, andrash. In milder cases, these symptoms last from two to seven days. A subset of patients, approximately 2−5% [8],can progress to a more severe presentation after four to six days of illness. Severe dengue includes denguehaemorrhagic fever (DHF) and dengue shock syndrome (DSS), which are marked by plasma leakage, haemorrhage,circulatory collapse, and multi-organ failure. The exact mechanisms underlying the progression to severe dengueare not fully understood, but they appear to involve a combination of viral and host factors, including the host'simmune response and genetic predisposition [1]. A median case fatality rate of 5% (range: 0−39%) was identifiedin a systematic review of observational studies analysing risk factors associated with mortality [11]. However,