Browsing by Author "Hanschmann, K-M.O."
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- Collaborative study to evaluate a candidate World Health Organization international standard for chikungunya virus for nucleic acid amplification technique (NAT)-based assaysPublication . KreB, J.A.; Hanschmann, K-M.O.; Chudy, M.; Collaborative Study GroupThis report describes the World Health Organization (WHO) project to develop an international standard (IS) for Chikungunya virus (CHIKV) RNA for use with nucleic acid amplification technique (NAT)-based assays. An international collaborative study was conducted to determine the potency of the candidate standard using a range of NAT-based assays for CHIKV, and to evaluate the suitability of the candidate for the calibration of secondary reference materials and the standardization of CHIKV viral load measurements. The candidate standard consisted of a heat inactivated CHIKV strain of the East/South/Central African genotype (ESCA), also known as the Indian Ocean Lineage, isolated from a patient returning from India to the United States in 20061 , diluted in human negative plasma. The lyophilized candidate preparation (Sample 1), the corresponding liquid-frozen bulk material (Sample 2) and three different clinical samples (Sample 3, Sample 4 and Sample 5) were included in the collaborative study. Twenty-five laboratories representing 14 countries participated in the study to evaluate the material using their routine CHIKV NAT assays. Twenty-four laboratories returned 31 data sets from 17 commercial assays and 14 in-house methods. Of these 31 methods, 11 were quantitative and 20 were qualitative. The results of the study indicate the suitability of the candidate material of the CHIKV strain of ESCA genotype (Sample 1) as the proposed 1st WHO IS for CHIKV. It is therefore proposed that the candidate material (PEI code 11785/16) is established as the 1st WHO IS for CHIKV RNA for NAT-based assays with an assigned potency of 2,500,000 International Units (IU)/mL when reconstituted in 0.5 mL of nuclease-free water. On-going studies for real-time and accelerated stability of the proposed IS indicate that the preparation is stable and suitable for long-term use under the proposed storage conditions.
- Harmonization of nucleic acid testing for Zika virus: development of the 1st World Health Organization International StandardPublication . Baylis, S.A.; Hanschmann, K-M.O.; Schnierle, D.S.; Trösemeier, J-H.; Blümel, J.; Zika Virus Collaborative Study GroupBACKGROUND: With the ongoing public health emergency due to Zika virus (ZIKV), nucleic acid testing (NAT) is essential for clinical diagnosis and screening of blood donors. However, NAT for ZIKV has not been standardized, and this study was performed to establish a World Health Organization (WHO) International Standard (IS) for ZIKV RNA; WHO ISs have been used to improve detection and quantification of blood-borne viruses. STUDY DESIGN AND METHODS: The candidate IS (cIS), code number 11468/16, was prepared by heat inactivation and lyophilization of a ZIKV strain isolated from a patient in French Polynesia in 2013. The cIS was evaluated together with other reference materials, including both Asian and African ZIKV lineages as well as a panel of clinical samples and in vitro-transcribed RNAs. The samples for evaluation were distributed to 24 laboratories from 11 countries. The assays used consisted of a mixture of in-house developed and commercial assays (available or in development). RESULTS: The potencies of the standards were determined by quantitative and qualitative assays. In total, 37 sets of data were analyzed: 19 from quantitative assays and 18 from qualitative assays. Data demonstrated wide variations in reported potencies of the cIS and the other study samples. CONCLUSIONS: Assay variability was substantially reduced when ZIKV RNA concentrations from the biological reference materials and clinical samples were expressed relative to the cIS. Thus, the WHO has established 11468/16 as the 1st IS for ZIKV RNA, with a unitage of 50,000,000 IU/mL.