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Linström MA, Preiser W, Nkosi NN, Vreede HW, Korsman SNJ, Zemlin AE, van Zyl GU. HIV false positive screening serology due to sample contamination reduced by a dedicated sample and platform in a high prevalence environment. PLoS One 2021; 16:e0245189. [PMID: 33428663 PMCID: PMC7799780 DOI: 10.1371/journal.pone.0245189] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 12/24/2020] [Indexed: 11/18/2022] Open
Abstract
Automated testing of HIV serology on clinical chemistry analysers has become common. High sample throughput, high HIV prevalence and instrument design could all contribute to sample cross-contamination by microscopic droplet carry-over from seropositive samples to seronegative samples resulting in false positive low-reactive results. Following installation of an automated shared platform at our public health laboratory, we noted an increase in low reactive and false positive results. Subsequently, we investigated HIV serology screening test results for a period of 21 months. Of 485 initially low positive or equivocal samples 411 (85%) tested negative when retested using an independently collected sample. As creatinine is commonly requested with HIV screening, we used it as a proxy for concomitant clinical chemistry testing, indicating that a sample had likely been tested on a shared high-throughput instrument. The contamination risk was stratified between samples passing the clinical chemistry module first versus samples bypassing it. The odds ratio for a false positive HIV serology result was 4.1 (95% CI: 1.69-9.97) when creatinine level was determined first, versus not, on the same sample, suggesting contamination on the chemistry analyser. We subsequently issued a notice to obtain dedicated samples for HIV serology and added a suffix to the specimen identifier which restricted testing to a dedicated instrument. Low positive and false positive rates were determined before and after these interventions. Based on measured rates in low positive samples we estimate that before the intervention, of 44 117 HIV screening serology samples, 753 (1.71%) were false positive, declining to 48 of 7 072 samples (0.68%) post-intervention (p<0.01). Our findings showed that automated high throughput shared diagnostic platforms are at risk of generating false-positive HIV test results, due to sample contamination and that measures are required to address this. Restricting HIV serology samples to a dedicated platform resolved this problem.
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Affiliation(s)
- Michael A Linström
- National Health Laboratory Service, Tygerberg Hospital, Cape Town, South Africa.,Division of Medical Virology, Department of Pathology, University of Stellenbosch, Cape Town, South Africa
| | - Wolfgang Preiser
- National Health Laboratory Service, Tygerberg Hospital, Cape Town, South Africa.,Division of Medical Virology, Department of Pathology, University of Stellenbosch, Cape Town, South Africa
| | - Nokwazi N Nkosi
- National Health Laboratory Service, Tygerberg Hospital, Cape Town, South Africa.,Division of Medical Virology, Department of Pathology, University of Stellenbosch, Cape Town, South Africa
| | - Helena W Vreede
- National Health Laboratory Service, Groote Schuur Hospital, Cape Town, South Africa.,Division of Chemical Pathology, Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - Stephen N J Korsman
- National Health Laboratory Service, Groote Schuur Hospital, Cape Town, South Africa.,Division of Medical Virology, Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - Annalise E Zemlin
- National Health Laboratory Service, Tygerberg Hospital, Cape Town, South Africa.,Division of Chemical Pathology, Department of Pathology, University of Stellenbosch, Cape Town, South Africa
| | - Gert U van Zyl
- National Health Laboratory Service, Tygerberg Hospital, Cape Town, South Africa.,Division of Medical Virology, Department of Pathology, University of Stellenbosch, Cape Town, South Africa
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Mueller SM, Menzi S, Kind AB, Blaich A, Bayer M, Navarini A, Itin P, Brandt O. Sexually transmitted coinfections in patients with anogenital warts - a retrospective analysis of 196 patients. J Dtsch Dermatol Ges 2020; 18:325-332. [PMID: 32291912 DOI: 10.1111/ddg.14060] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 08/23/2019] [Indexed: 11/27/2022]
Abstract
BACKGROUND AND OBJECTIVES Anogenital warts (AGWs) are most commonly caused by low-risk human papillomavirus (HPV) types, and although they are the most frequent viral sexually transmitted infections (STIs), little is known about STI coinfections in affected patients. We therefore sought to assess STI coinfection rates in patients with AGW, specify STI coinfections and calculate the number needed to screen (NNS) for each STI. METHODS A retrospective cross-sectional study analyzing data sets from AGW patients treated in our clinic between 2008-2016. RESULTS 142/196 (72 %) patients had been variably screened for infections with HIV, HBV and HCV, Treponema pallidum, Neisseria gonorrhoeae, Chlamydia trachomatis, Mycoplasma genitalium and HSV. The STI coinfection rate in all tested patients was 24.6 %, yielding an NNS of 4.1 to detect any STI. Of note, the coinfection rate did not differ significantly between heterosexual men, homosexual men and women, respectively. The NNS for syphilis was 8.4, for HIV 14.0, for HCV 28.5 and for HBV 39.0. The NNS for asymptomatic patients tested for HSV, Chlamydia trachomatis and Mycoplasma genitalium were 1.4, 5.3 and 12.0, respectively. CONCLUSION Due to the high prevalence of STI coinfections, AGW patients should be screened for other STIs.
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Affiliation(s)
- Simon M Mueller
- Department of Dermatology, University Hospital Basel, Basel, Switzerland
| | - Sheryl Menzi
- Department of Dermatology, University Hospital Basel, Basel, Switzerland
| | - André B Kind
- Colposcopy Unit, Department of Gynecology, University Hospital Basel, Basel, Switzerland
| | - Annette Blaich
- Division of Clinical Microbiology, University Hospital Basel, Basel, Switzerland
| | - Michael Bayer
- Department of Dermatology, University Hospital Basel, Basel, Switzerland.,Medici Aerztezentrum, Zell, Switzerland
| | - Alexander Navarini
- Department of Dermatology, University Hospital Basel, Basel, Switzerland
| | - Peter Itin
- Department of Dermatology, University Hospital Basel, Basel, Switzerland
| | - Oliver Brandt
- Department of Dermatology, University Hospital Basel, Basel, Switzerland
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Tang Z, Gou Y, Zhang K, Zhao Z, Wei Y, Li D, Chen L, Tao C. The evaluation of low cut-off index values of Elecsys ® HIV combi PT assay in predicting false-positive results. J Clin Lab Anal 2020; 34:e23503. [PMID: 32841422 PMCID: PMC7676207 DOI: 10.1002/jcla.23503] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Revised: 06/19/2020] [Accepted: 07/13/2020] [Indexed: 02/05/2023] Open
Abstract
Objective To analyze the results of different cut‐off index (COI) values of Elecsys® HIV combi PT assay and to assess the role of COI in reducing the frequency of false‐positive results. Methods We conducted a retrospective study of samples analyzed by Elecsys® HIV combi PT assay, a 4th‐generation ECLIA, between 2016 and 2017. A total amount of 379 122 samples were collected for HIV (Human Immunodeficiency Virus) screening. Results A total of 379 122 samples were analyzed. 2528 (0.67%) were positive by Elecsys® HIV combi PT. Of these, 468 were false‐positive results, and most of them (94.87%) were in samples with 1 < COI < 15. The false‐positive rate was 0.12%. Patients with false‐positive samples were more distributed in elder (P < .001) and female (P < .001) than true‐positive specimens. The median COI in true‐positive specimens was (385.20), which is significantly higher than false‐positive specimens (2.08). The consistency between Elecsys® HIV combi PT assay and 3rd‐generation and positive predictive value (PPV) increased with higher COI values. Cancer, infection, and neurological diseases were considered the potential confounding factors of HIV false‐positive results (19.44%, 11.11%, and 6.62%, respectively). Conclusion Samples with low COI values, especially those contain confounding factors, need to be further scrutinized to determine whether the confounding factors may cause false‐positive problem. In addition, the hypothesis that low COI values may predict false‐positive results is valid.
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Affiliation(s)
- Zhuoyun Tang
- Department of Laboratory Medicine, West China Hospital of Sichuan University, Chengdu, China
| | - Yu Gou
- Department of Laboratory Medicine, West China Hospital of Sichuan University, Chengdu, China.,West China Second University Hospital of Sichuan University, Chengdu, China
| | - Keyi Zhang
- Department of Laboratory Medicine, West China Hospital of Sichuan University, Chengdu, China
| | - Zhongyi Zhao
- Department of Laboratory Medicine, West China Hospital of Sichuan University, Chengdu, China
| | - Yinhao Wei
- Department of Laboratory Medicine, West China Hospital of Sichuan University, Chengdu, China
| | - Dongdong Li
- Department of Laboratory Medicine, West China Hospital of Sichuan University, Chengdu, China
| | - Li Chen
- Department of Laboratory Medicine, West China Hospital of Sichuan University, Chengdu, China.,Clinical Lab, Wenjiang Zhongyi Hospital, Chengdu, China
| | - Chuanmin Tao
- Department of Laboratory Medicine, West China Hospital of Sichuan University, Chengdu, China
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Bailey AL, Anderson N. Risks of requiring a dedicated molecular specimen for HIV diagnosis and a potential strategy for mitigation. PLoS One 2020; 15:e0237580. [PMID: 32790740 PMCID: PMC7425950 DOI: 10.1371/journal.pone.0237580] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2019] [Accepted: 07/30/2020] [Indexed: 11/18/2022] Open
Abstract
Background HIV screening (i.e. antigen/antibody) tests are followed by a supplemental (i.e. antibody-only) if the screen is positive. Discrepant results can result from two scenarios: a false-positive screening test or acute HIV infection. These scenarios can be distinguished by a molecular HIV test, but due to contamination concerns, our laboratory recently implemented a policy requiring a second specimen dedicated for molecular HIV testing. Our objective was to (1) characterize the effect of this policy on the time-to-diagnosis for patients with discrepant screening and supplemental test results, and (2) explore “strength of positivity” as an interim predictor of screening test accuracy while awaiting confirmatory test results. Methods Data from our laboratory information system, electronic health record, and instrument logs were used to collate data for all HIV testing performed at Barnes-Jewish Hospital (BJH) between January 1, 2014 and October 18, 2017. Results Requiring a dedicated specimen for molecular testing significantly increased the time-to-diagnosis for patients with discrepant screening and supplemental HIV tests (p = 0.0084). This policy also contributed to loss-to-followup, with 0/35 discrepant cases lost-to-followup prior to policy implementation compared to 2/10 after implementation. However, by optimizing the signal-to-cutoff (S/CO) ratio of the screening test, we were able to more accurately distinguish false-positives from acute-HIV prior to molecular testing (sensitivity of 100%, specificity of 89%). Conclusions We propose utilizing quantitative fourth-generation assay results (S/CO) ratios as a predictor of infection true positivity in situations where the screening assay is reactive but the supplemental test is negative and confirmatory molecular results are not immediately available.
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Affiliation(s)
- Adam L. Bailey
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, United States of America
| | - Neil Anderson
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, United States of America
- * E-mail:
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Mueller SM, Menzi S, Kind AB, Blaich A, Bayer M, Navarini A, Itin P, Brandt O. Sexuell übertragbare Koinfektionen bei Patienten mit anogenitalen Warzen – eine retrospektive Analyse von 196 Patienten. J Dtsch Dermatol Ges 2020; 18:325-333. [DOI: 10.1111/ddg.14060_g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 08/23/2019] [Indexed: 11/29/2022]
Affiliation(s)
| | - Sheryl Menzi
- Dermatologische KlinikUniversitätsspital Basel Basel Schweiz
| | - André B. Kind
- Abteilung KolposkopieFrauenklinikUniversitätsspital Basel Basel Schweiz
| | - Annette Blaich
- Abteilung Klinische MikrobiologieUniversitätsspital Basel Basel Schweiz
| | - Michael Bayer
- Dermatologische KlinikUniversitätsspital Basel Basel Schweiz
- Medici Ärztezentrum Zell Schweiz
| | | | - Peter Itin
- Dermatologische KlinikUniversitätsspital Basel Basel Schweiz
| | - Oliver Brandt
- Dermatologische KlinikUniversitätsspital Basel Basel Schweiz
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Demir T, Yalcin S, Kilic S. Evaluation of the diagnostic performance and optimal cutoff value of a fourth-generation ELISA, VIDAS HIV-1/2 Duo Ultra assay, in a low-prevalence country. Diagn Microbiol Infect Dis 2020; 97:115011. [PMID: 32139113 DOI: 10.1016/j.diagmicrobio.2020.115011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Revised: 12/07/2019] [Accepted: 01/27/2020] [Indexed: 11/25/2022]
Abstract
In this study, we described the largest analysis to date conducted with VIDAS® HIV Duo Ultra assay. Additionally, we analyzed the diagnostic performance and cutoff values (TV) of HIV Duo Ultra assay and total cost analysis for HIV testing. Of 11,642 enzyme-linked immunosorbent assay (ELISA)-positive samples referred to our center for confirmation, 2000 were positive with HIV Duo Ultra, and of these, 87% were HIV-1 positive and 0.6% were HIV-1 indeterminate with the confirmatory test. Overall, the false-positivity rate was 1.75% for HIV Duo Ultra assay. The sensitivity and specificity were 100% and 99.1%, respectively, when the TV was set at the recommended cutoff value. Even increasing the cutoff value four times, sensitivity and specificity remained high, pointing out that a TV of 0.99 is highly indicative of HIV positivity. Retesting samples with HIV Duo Ultra assay decreased 80% of the confirmatory tests, revealing a significant decrease of 78% in the total costs and reporting time.
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Affiliation(s)
- Tulin Demir
- Ministry of Health, Public Health Institute, National Reference Laboratory for HIV/AIDS and Viral Hepatitis Department, Ankara, Turkey.
| | - Suleyman Yalcin
- Ministry of Health, Public Health Institute, National Reference Laboratory for HIV/AIDS and Viral Hepatitis Department, Ankara, Turkey
| | - Selcuk Kilic
- Ministry of Health, Public Health Institute, National Reference Laboratory for HIV/AIDS and Viral Hepatitis Department, Ankara, Turkey; University of Health Sciences, Istanbul Medical Faculty, Department of Medical Microbiology, İstanbul, Turkey
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Decreased Seroreactivity in Individuals Initiating Antiretroviral Therapy during Acute HIV Infection. J Clin Microbiol 2019; 57:JCM.00757-19. [PMID: 31217270 DOI: 10.1128/jcm.00757-19] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 06/14/2019] [Indexed: 01/24/2023] Open
Abstract
Antiretroviral therapy (ART) during acute HIV infection (AHI) interrupts viral dynamics and may delay the emergence of serological markers targeted by current HIV screening and confirmatory assays, thus creating challenges for correctly classifying HIV infection status. The performance of three HIV antigen/antibody combination (HIV Ag/Ab Combo) assays (the Bio-Rad GS, Abbott Architect, and Bio-Rad BioPlex 2200 assays) was evaluated with samples collected from RV254/South East Asia Research Collaboration in HIV 010 (RV254/SEARCH010) study (Bangkok, Thailand) participants at weeks 12 and 24 following the initiation of ART at Fiebig stage I (FI) (n = 23), FII (n = 39), or FIII/IV (n = 22). Supplemental, confirmatory testing was performed by the Geenius HIV 1/2 and HIV-1 Western blot assays (Bio-Rad). Samples from 30 untreated, HIV-1-infected individuals demonstrated robust HIV Ag/Ab Combo assay reactivity with well-developed HIV-1 Western blotting profiles by 24 weeks after infection. In contrast, 52.2% of samples from individuals initiating ART at FI, 7.7% of samples from individuals initiating ART at FII, and 4.5% of samples from individuals initiating ART at FIII/IV were nonreactive by the HIV Ag/Ab Combo assays, with 36.4 to 39.1% of samples having low signal-to-cutoff (S/CO) results by the Architect and BioPlex assays (S/CO < 10). Seroreversion from a reactive to a nonreactive status was observed in 10 individuals initiating ART at FII and 3 individuals initiating ART at FIII/IV. The Geenius and HIV-1 Western blot assay results were negative or indeterminate for 73.9% and 69.6% of individuals, respectively, treated at FI; 50.0% and 26.3% of individuals, respectively, treated at FII; and 54.5% and 40.9% of individuals, respectively, treated at FIII/IV. Virologic suppression of HIV-1 by ART during AHI impedes seroconversion to biomarkers of infection, limiting the utility of HIV Ag/Ab Combo and supplemental, confirmatory assays for infection status determination.
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Avidor B, Chemtob D, Turner D, Zeldis I, Girshengorn S, Matus N, Achsanov S, Gielman S, Schweizer I, Baskin L, Schreiber L, Kra-Oz Z. Evaluation of the virtues and pitfalls in an HIV screening algorithm based on two fourth generation assays - A step towards an improved national algorithm. J Clin Virol 2018; 106:18-22. [PMID: 30007138 DOI: 10.1016/j.jcv.2018.06.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2018] [Revised: 06/08/2018] [Accepted: 06/30/2018] [Indexed: 11/18/2022]
Abstract
BACKGROUND Fourth-generation immunoassays used for HIV screening, simultaneously detect anti-HIV antibodies and HIV-1 P24 antigen, but are prone to false-positive results. Usually, they are followed by highly specific third-generation assay, able to differentiate between HIV-1/2 infections. In Israel, screening algorithm is based on consecutive testing by two fourth-generation assays and confirmation by a third-generation test. OBJECTIVES To evaluate the performance of this algorithm. STUDY DESIGN Architect HIV1/2 Combo (Combo) reactive results were tested by Vidas HIV Duo Ultra (VD). Confirmation was by INNO-LIA HIV 1/2 or Geenius assays. Five-year results were retrospectively analyzed. HIV true positives (TPs), acute infected (AI), false-positives (FPs) and HIV negatives, were as defined by the algorithm. RESULTS 501,338 individuals were screened, of which 956 were TPs, 64 AI and 30 F Ps. Specificity was almost 100% and positive predictive value 97%. VD was negative in 94% of confirmed Combo false-reactive individuals. The Combo results in the first tested sample differed substantially between TPs, AI and FPs, enabling the determination of a cutoff value that distinguished 94% of TPs and AI from FPs. CONCLUSIONS An algorithm is suggested that will use a single sample collection. HIV negative diagnosis will be based on Combo unreactive or Combo reactive/VD negative results. HIV positive diagnosis will be based on Combo reactive/ VD positive results, given a Combo value above a designated cutoff. Below this cutoff samples will be tested by a molecular assay. Since HIV-2 rarely occurs in Israel, the use of a third-generation confirmation assay should be discussed.
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Affiliation(s)
- Boaz Avidor
- Laboratory for Viruses and Molecular Biology, Tel-Aviv Sourasky Medical Center, Tel-Aviv, Israel; Crusaid Kobler AIDS Center, Tel-Aviv Sourasky Medical Center, Tel-Aviv Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel.
| | - Daniel Chemtob
- Department of Tuberculosis and AIDS, Israel Ministry of Health, Jerusalem, Israel; Braun School of Public Health and Community Medicine, Faculty of Medicine, Hebrew University-Hadassah, Jerusalem, Israel
| | - Dan Turner
- Crusaid Kobler AIDS Center, Tel-Aviv Sourasky Medical Center, Tel-Aviv Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Irene Zeldis
- Laboratory for Viruses and Molecular Biology, Tel-Aviv Sourasky Medical Center, Tel-Aviv, Israel; Crusaid Kobler AIDS Center, Tel-Aviv Sourasky Medical Center, Tel-Aviv Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Shirley Girshengorn
- Laboratory for Viruses and Molecular Biology, Tel-Aviv Sourasky Medical Center, Tel-Aviv, Israel; Crusaid Kobler AIDS Center, Tel-Aviv Sourasky Medical Center, Tel-Aviv Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Natalia Matus
- Laboratory for Viruses and Molecular Biology, Tel-Aviv Sourasky Medical Center, Tel-Aviv, Israel; Crusaid Kobler AIDS Center, Tel-Aviv Sourasky Medical Center, Tel-Aviv Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Svetlana Achsanov
- Laboratory for Viruses and Molecular Biology, Tel-Aviv Sourasky Medical Center, Tel-Aviv, Israel; Crusaid Kobler AIDS Center, Tel-Aviv Sourasky Medical Center, Tel-Aviv Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Simona Gielman
- Laboratory for Viruses and Molecular Biology, Tel-Aviv Sourasky Medical Center, Tel-Aviv, Israel; Crusaid Kobler AIDS Center, Tel-Aviv Sourasky Medical Center, Tel-Aviv Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Inbal Schweizer
- Laboratory for Viruses and Molecular Biology, Tel-Aviv Sourasky Medical Center, Tel-Aviv, Israel; Crusaid Kobler AIDS Center, Tel-Aviv Sourasky Medical Center, Tel-Aviv Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Lilya Baskin
- Virology Laboratory, Rambam Health Care Campus, Haifa, Israel
| | | | - Zipi Kra-Oz
- Virology Laboratory, Rambam Health Care Campus, Haifa, Israel
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