Improved efficiency using sequential automated immunoassays for syphilis screening in blood donors.

Using sequential immunoassays for the screening of blood donors is well described for viral serology testing but not for the screening of syphilis. In this study, we report the evaluation results and 2-year sequential testing data using two highly sensitive automated serology assays, the Alinity s Syphilis chemiluminescent immunoassay for screening, with all repeatedly reactive samples then tested on the Elecsys Syphilis electrochemiluminescence immunoassay. We screened 1,767,782 blood donor samples between 7 July 2021 and 6 July 2023 and found the Alinity false-positive rate to be low at 0.08% (1,456/1,767,782). The common false-positive rate between the two assays was also low (3.83%, 58/1,514). Concordantly reactive samples were further tested using a Treponema pallidum particle agglutination test, a rapid plasma reagin test, and a fluorescent treponemal antibody absorption test. There were 262/1,376 concordantly reactive Alinity and Elecsys blood donor samples with reactivity on one or more of the confirmatory tests. A total of 26/1,376 donors had a current syphilis infection, 152/1,376 reported a past history of syphilis and had been treated, and 84/1,376 did not report a past history of syphilis. We suggest that future studies could explore the use of sequential immunoassays to aid in the serodiagnosis for syphilis. IMPORTANCE: The serodiagnosis for syphilis usually follows two methodologies-a "traditional" algorithm using a non-treponemal test followed by confirmation using a treponemal test, or a "reverse" algorithm using a treponemal test followed by a non-treponemal test. There are limited reports in the literature of using a modified reverse algorithm (treponemal test followed by a second treponemal test), and to the best of knowledge, there are currently no published articles using two highly sensitive automated immunoassays to aid the serodiagnosis of syphilis. In addition, the Treponema pallidum particle agglutination (TPPA) assay is commonly used as a confirmatory test for the diagnosis of syphilis. With the withdrawal of the TPPA assay from Australia and presumably from the global market also, alternative testing algorithms are now required. This study provides proof of concept for using sequential immunoassays in the diagnosis of syphilis.

New tatt? We're ok with that! Relaxing the tattoo deferral for plasmapheresis donors maintains safety and increases donations.

BACKGROUND AND OBJECTIVES: Tattooing is one of the leading donor deferral reasons in Australia. Until September 2020, donors were deferred from all donation types for 4 months after a tattoo. At this time, our guideline changed such that donations of plasma for further manufacture were accepted immediately, provided the tattoo was administered in a licensed or regulated Australian establishment. We examined the effects of this change. MATERIALS AND METHODS: Donors with a tattoo deferral in the 2 years before or after the guideline change were identified and followed up until 3 November 2022. Between the two periods, we compared blood-borne virus (BBV) incidence, donor return, and the number of donors and donations regained after deferral. RESULTS: The incidence of BBV infection in donors after a tattoo deferral was zero in both periods. To exceed a residual risk of 1 in 1 million for hepatitis C virus, 190 donors would need to be infected yearly from a tattoo. Donors returned to donate significantly faster after the change (median return 85 days compared with 278 days). An extra 187 donations per 10,000 person-years of observation were gained, yielding a total of 44,674 additional plasma donations nationally 0-4 months after getting a tattoo. CONCLUSION: Allowing plasma donations immediately post-tattoo resulted in a substantial donation gain with no adverse safety effect. Lifeblood subsequently reduced the deferral for transfusible component donations to 7 days for tattoos in Australian licensed/regulated establishments.

Has the frequency of ABO RhD blood groups in Australian blood donors changed as a result of the removal of the variant Creutzfeldt-Jakob disease-based deferral?

BACKGROUND AND OBJECTIVES: Until 25 July 2022, Australians who had spent more than 6 months in the United Kingdom or territories between 1980 and 1996 were deferred from blood donation due to the risk of variant Creutzfeldt-Jakob disease. Removal of this geography-based donor deferral on RhD-negative blood availability has not been reported. MATERIALS AND METHODS: All donors who donated at least once from 25 July 2022 to 25 July 2023 were included. UK donor status, first-time donor and ABO RhD data were extracted from the National Blood Management System. RESULTS: Data from 566,447 blood donors with a valid ABO RhD result were analysed. Of these, 34,560 were new or returning lapsed donors following removal of the UK donor deferral. The median age [range] in years for all donors was 43 [75] with UK donors being older 53 [70]. There was a higher prevalence of RhD-negative status in UK donors (20.2%) compared with first-time blood donors (15.7%). CONCLUSION: UK donors were generally older, female and more likely to be RhD-negative. Although UK donors provided a boost to RhD-negative blood collections, the overall prevalence of ABO RhD blood groups in the total Australian blood donor panel remained similar to previous estimates.

Seroprevalence of Japanese encephalitis virus-specific antibodies in Australia following novel epidemic spread: protocol for a national cross-sectional study.

INTRODUCTION: Japanese encephalitis virus (JEV) is a mosquito-borne flavivirus that causes encephalitis and other morbidity in Southeast Asia. Since February 2022, geographically dispersed JEV human, animal and vector detections occurred on the Australian mainland for the first time. This study will determine the prevalence of JEV-specific antibodies in human blood with a focus on populations at high risk of JEV exposure and determine risk factors associated with JEV seropositivity by location, age, occupation and other factors. METHOD: Samples are collected using two approaches: from routine blood donors (4153 samples), and active collections targeting high-risk populations (convenience sampling). Consent-based sampling for the latter includes a participant questionnaire on demographic, vaccination and exposure data. Samples are tested for JEV-specific total antibody using a defined epitope-blocking ELISA, and total antibody to Australian endemic flaviviruses Murray Valley encephalitis and Kunjin viruses. ANALYSIS: Two analytic approaches will occur: descriptive estimates of seroprevalence and multivariable logistic regression using Bayesian hierarchical models. Descriptive analyses will include unadjusted analysis of raw data with exclusions for JEV-endemic country of birth, travel to JEV-endemic countries, prior JEV-vaccination, and sex-standardised and age-standardised analyses. Multivariable logistic regression will determine which risk factors are associated with JEV seropositivity likely due to recent transmission within Australia and the relative contribution of each factor when accounting for effects within the model. ETHICS: National Mutual Acceptance ethical approval was obtained from the Sydney Children's Hospitals Network Human Research Ethics Committee (HREC). Local approvals were sought in each jurisdiction. Ethical approval was also obtained from the Australian Red Cross Lifeblood HREC. DISSEMINATION: Findings will be communicated to participants and their communities, and human and animal health stakeholders and policy-makers iteratively and after final analyses. Understanding human infection rates will inform procurement and targeted allocation of limited JEV vaccine, and public health strategies and communication campaigns, to at-risk populations.