Emergence of genetically linked vaccine-originated poliovirus type 2 in the absence of oral polio vaccine, Jerusalem, April to July 2022.

We report an emergence and increase in poliovirus type 2 detection via routine wastewater surveillance in three non-overlapping regions in the Jerusalem region, Israel, between April and July 2022. Sequencing showed genetic linkage among isolates and accumulation of mutations over time, with two isolates defined as vaccine-derived polioviruses (VDPV). This demonstrates the emergence and potential circulation of type 2 VDPV in a high-income country with high vaccine coverage and underscores the importance of routine wastewater surveillance during the polio eradication.

HIV-1 infection among women in Israel, 2010-2018.

INTRODUCTION: Although women comprise 33% of the HIV-1-carriers in Israel, they have not previously been considered a risk group requiring special attention. Immigration waves from countries in Africa and in East Europe may have changed the local landscape of women diagnosed with HIV-1. Here, we aimed to assess viral and demographic characteristics of HIV-1-positive women identified in Israel between 2010 and 2018. METHODS: All > 16 year-old, HIV-1-infected women, diagnosed in Israel in 2010-2018, (n = 763) registered in the National HIV reference laboratory were included in this cross-sectional study. Demographic and clinical characteristics were extracted from the database. Viral subtypes and transmitted drug resistance mutations (TDRM) were determined in 337 (44.2%) randomly selected samples collected from treatment-naive women. RESULTS: Median age at diagnosis was 38 years. Most (73.3%) women were immigrants from the former Soviet Union (FSU) (41.2%, 314) or sub-Saharan Africa (SSA) (32.2%, 246) and carried subtype A (79.7%) or C (90.3%), respectively. Only 11.4% (87) were Israeli-born women. Over the years, the prevalence of women from SSA decreased while that of women from FSU increased significantly (p < 0.001). The median CD4+ cell count was 263 cells/mm3, and higher (391 cells/mm3) in Israeli-born women. TDRM were identified in 10.4% of the tested samples; 1.8, 3 and 7.1% had protease inhibitors (PI), nucleotide reverse transcriptase inhibitors (NRTI) and non-nucleoside reverse transcriptase inhibitors (NNRTI) TDRM, respectively. The prevalence of women with NNRTI TDRM significantly increased from 4.9% in 2010-2012 to 13.3% in 2016-2018. Israeli-born women had the highest prevalence (16.3%) of NNRTI TDRM (p = 0.014). NRTI A62 (5.6%), NNRTI E138 and K103 (5.6 and 4.2%, respectively) were the most prominent mutated sites. CONCLUSIONS: Most HIV-1-positive women diagnosed in Israel in 2010-2018 were immigrants, with the relative ratio of FSU immigrants increasing in recent years. The high proportion of women diagnosed with resistance mutations, particularly, the yearly increase in the frequency of NNRTI mutations, support the national policy of resistance testing at baseline.

HIV-1/2 screening in blood centers: implementing a two-step serological screening assay approach to reduce donor deferral.

BACKGROUND: Screening blood donations for human immunodeficiency virus 1/2 (HIV-1/2) infection in blood centers is often done with a highly sensitive 3rd-generation immunoassay which may cause false-positive results. Donations found repeatedly reactive (RR) are discarded regardless of negative HIV-1/2 nucleic acid testing (NAT) and confirmatory assays results. These donors are notified and deferred if RR in a subsequent donation. We evaluated the introduction of a secondary 4th-generation serological assay to the overall algorithm performance. METHODS: All donations collected between January 2016 and May 2018 (574,338) were screened using 3rd-generation immunoassay (PRISM HIV O Plus) and NAT (Procleix Ultrio/Ultrio Elite). Serology RR donations were tested with 4th-generation Architect HIV Ag/Ab Combo and Vidas HIV Duo Ultra and a confirmatory assay (Geenius HIV-1/2). RESULTS: The two 4th-generation assays found that 86% (179/209 on Architect) and 94% (182/193 on Vidas) of the 3rd-generation immunoassay RR were negative for HIV-1/2, which were also negative by confirmatory assay. Only 14% (30/209 on Architect) and 6% (11/193 on Vidas) that were 3rd-generation HIV-1/2 RR required confirmation, of which eight donors were confirmed as HIV positive. The probability of missing an HIV-1 infected donor by this algorithm is one in a million RR cases. CONCLUSION: The introduction of a two-step serological screening algorithm in blood centers whereby 4th-generation assay will be performed for all 3rd-generation RR blood donors will reduce the number of donations requiring confirmation, save time and money, and most importantly, reduce the number of discarded blood donations and allow re-entry processes.

Hepatitis E in pigs in Israel: seroprevalence, molecular characterisation and potential impact on humans.

IntroductionThe zoonotic hepatitis E virus (HEV) genotype 3 (HEV-G3) has become a common cause of acute and chronic hepatitis among humans worldwide. In Israel, while HEV-3 sequences have previously been detected in sewage, only the non-zoonotic HEV-G1 genotype has been found in samples from human patients.AimIn this pilot study, we aimed to assess the status of HEV in a sample of the swine population and among swine farm workers in Israel.MethodsPig blood (n = 141) and faecal samples (n = 39), pig farm sewage samples (n = 8) and blood from farm workers (n = 24) were collected between February 2016 and October 2017. Anti-HEV IgG was detected using the Wantai assay. HEV RNA was analysed with the RealStar HEV kit. HEV open reading frame 1 fragments amplified from representative HEV RNA-positive samples were used for phylogenetic analysis.ResultsOverall prevalence of HEV antibodies in pigs was 75.9% (107/141). HEV RNA was detected in plasma (2.1%, 3/141), faecal (22.8%, 18/79) and pig sewage (4/8) samples. Pig and sewage-derived viral sequences clustered with previously identified human sewage HEV-G3 sequences. Most pig farms workers (23 of 24) were HEV-seropositive; none was viraemic or reported previous clinical signs.ConclusionsThis study showed that domestic pigs in Israel are infected with HEV-G3. The high HEV seropositivity of the farm workers together with the previous identification of this virus in human sewage suggests circulation to humans. The clinical impact of these findings on public health should be further explored.

Prevalence of hepatitis E virus antibodies, Israel, 2009-2010.

We investigated prevalence of hepatitis E virus in a sample of the population of Israel. The overall seroprevalence of antibodies to the virus was 10.6% (95% CI 8.4%-13.0%); age-adjusted prevalence was 7.6%. Seropositivity was associated with age, Arab ethnicity, low socioeconomic status, and birth in Africa, Asia, or the former Soviet Union.

Evaluation of the RealTime HIV-1, Xpert HIV-1, and Aptima HIV-1 Quant Dx Assays in Comparison to the NucliSens EasyQ HIV-1 v2.0 Assay for Quantification of HIV-1 Viral Load.

HIV-1 RNA monitoring, both before and during antiretroviral therapy, is an integral part of HIV management worldwide. Measurements of HIV-1 viral loads are expected to assess the copy numbers of all common HIV-1 subtypes accurately and to be equally sensitive at different viral loads. In this study, we compared for the first time the performance of the NucliSens v2.0, RealTime HIV-1, Aptima HIV-1 Quant Dx, and Xpert HIV-1 viral load assays. Plasma samples (n = 404) were selected on the basis of their NucliSens v2.0 viral load results and HIV-1 subtypes. Concordance, linear regression, and Bland-Altman plots were assessed, and mixed-model analysis was utilized to compare the analytical performance of the assays for different HIV-1 subtypes and for low and high HIV-1 copy numbers. Overall, high concordance (>83.89%), high correlation values (Pearson r values of >0.89), and good agreement were observed among all assays, although the Xpert and Aptima assays, which provided the most similar outputs (estimated mean viral loads of 2.67 log copies/ml [95% confidence interval [CI], 2.50 to 2.84 log copies/ml] and 2.68 log copies/ml [95% CI, 2.49 to 2.86 log copies/ml], respectively), correlated best with the RealTime assay (89.8% concordance, with Pearson r values of 0.97 to 0.98). These three assays exhibited greater precision than the NucliSens v2.0 assay. All assays were equally sensitive for subtype B and AG/G samples and for samples with viral loads of 1.60 to 3.00 log copies/ml. The NucliSens v2.0 assay underestimated A1 samples and those with viral loads of >3.00 log copies/ml. The RealTime assay tended to underquantify subtype C (compared to the Xpert and Aptima assays) and subtype A1 samples. The Xpert and Aptima assays were equally efficient for detection of all subtypes and viral loads, which renders these new assays most suitable for clinical HIV laboratories.

Recent HIV-1 infection in Israel 2017-2021: Evaluation of geenius and HIV-1/2 combo assays for identifying recent infection detected by Sedia assay and assessment of factors related to recent infection: Recent HIV-1 infection in Israel.

BACKGROUND: Estimating HIV-1 recency of infection for incidence and local outbreaks detection usually involves specifically designed assays. Here, we established an approach to identify recent infections, estimate their rate, and assess potential risk factors. METHODS: Randomly selected HIV-1 positive samples (n = 382) collected in 2017-2021 were tested by Sedia and compared to the results of Geenius recency algorithm and the S/CO values of the HIV-1/2 Combo assay. Using Geenius and Combo recency verdict, we assessed all cases diagnosed in 2017-2021. Related factors were further assessed. RESULTS: While Geenius and Combo had a sensitivity of 65.9 % and 89.30 %, respectively, and specificity of 96 % and 90 %, respectively, compared to Sedia, higher concordance (97.2 %) and kappa (>0.9) were observed when the verdict of both assays together was compared to Sedia. Using this approach, 15.3 % (238/1548) of individuals diagnosed in 2017-2021 were defined as recently infected. In multivariate analysis, recent diagnosis was mainly associated with men who have sex with men (MSM) and with birthplace in Israel, Western/Central Europe, or North America. CONCLUSIONS: Only 15.3 % of infections in 2017-2021, mainly in MSM and Israeli/Western countries-born individuals, were diagnosed early. Regular diagnostic assays have a potential to identify and monitor trends in recent infections.

Parvovirus B19 Outbreak in Israel: Retrospective Molecular Analysis from 2010 to 2023.

This study presents an analysis of the epidemiological trends of parvovirus B19 (B19V) in Israel from 2010 to 2023, with particular emphasis on the outbreak in 2023. The analysis utilized molecular diagnostic data from individual patients obtained at the Central Virology Laboratory. Between 2010 and 2022, 8.5% of PCR-tested samples were positive for B19V, whereas in 2023, this percentage surged to 31% of PCR-tested samples. Throughout the study period, annual cycles consistently peaked in early spring/summer, with the most recent prominent outbreak occurring in 2016. Predominantly, diagnoses were made in children and women aged 20-39. Despite the notable surge in 2023, over 80% of positive cases continued to be observed in children and young women, with a decrease in cases during winter months. Furthermore, genotype 1a of the virus remained the predominant strain circulating during the outbreak. In light of these circumstances, consideration should be given to implementing screening measures, particularly among high-risk groups such as pregnant women.

Dengue Types 1 and 3 Identified in Travelers Returning from Kathmandu, Nepal, during the October 2022 Outbreak Are Related to Strains Recently Identified in India.

Phylogenetic analysis of dengue serotypes 1 and 3, which were diagnosed in travelers and Nepalese infected in Kathmandu during the October 2022 outbreak, revealed that both serotypes were clustered closest to the sequences sampled in India. This suggests both serotypes may have originated in India.

Factors Associated with Virological Failure in First-Line Antiretroviral Therapy in Patients Diagnosed with HIV-1 between 2010 and 2018 in Israel.

Despite the progress in contemporary antiretroviral therapy (ART) and the continuous changes in treatment guidelines, virological failure (VF) is still an ongoing concern. The goal of this study was to assess factors related to VF after first-line ART. A longitudinal cohort retrospective study of individuals on first-line ART diagnosed with HIV-1 in 2010-2018 and followed-up for a median of two years was conducted. Demographics, baseline and longitudinal CD4 counts, treatment regimens, adherence and VF were recorded. The Cox proportional hazards regression and mixed models were used. A cohort of 1130 patients were included. Overall, 80% were males and 62% were Israeli-born individuals. Compared to individuals diagnosed in 2010-2014, when treatment was initiated according to CD4 levels, those diagnosed in 2015-2018 were older and had lower baseline CD4 counts. VF was recorded in 66 (5.8%) patients. Diagnosis with CD4 <200 cells/mmᶟ with AIDS-defining conditions (HR = 2.75, 95%CI:1.52-4.97, p < 0.001) and non-integrase strand transfer inhibitor regimens (non-INSTI, HR = 1.80, 95%CI:1.01-3.24, p = 0.047) increased VF risk. No impact of baseline resistance was observed. We concluded that the early detection of HIV-1 infection and usage of INSTI-based regimens are recommended to reduce VF.

Evaluation of Biotrin, Serion and Euroimmun commercial assays for the detection of parvovirus B19-specific IgM and IgG antibodies.

Diagnosis of parvovirus B19 (B19) infection in small-medium size clinical laboratories is most often done by nonautomated enzyme immunoassays (EIAs). Using 195 specimens we compared the analytical performance of Biotrin (Dublin, Ireland), Euroimmun (Lubeck, Germany), and Serion (Würzburg, Germany) EIAs. Sensitivity, specificity, and concordance to Biotrin assay were calculated. Overall complete agreement in the IgG and IgM results was 88.7% (173/195) and 75.9% (148/195) samples, respectively. When equivocal results were considered positive, Serion and Euroimmun highly agreed (>93.8%) with Biotrin in the IgG serology. Serion had better IgM sensitivity and specificity than Euroimmun when compared to Biotrin, although more Serion IgM equivocal results needed reflex testing. Clinical interpretation by all three assays was identical in 83% of the samples. We concluded that overall the performance of these assays was similar and both Serion and Euroimmun could be a suitable replacement for the Biotrin.

HIV-1 Circulating Recombinant Forms (CRFs) and Unique Recombinant Forms (URFs) in Israel, 2010-2018.

Monitoring HIV-1 circulating recombinant forms (CRFs) and unique recombinant forms (URFs) is important for disease surveillance. Recombination may affect prevention efforts and interfere with the diagnosis and treatment of HIV-1 infection. Here, we characterized the epidemiology of HIV-1 CRFs and URFs in Israel. Partial pol sequences from treatment naïve patients diagnosed in 2010−2018 were assessed using the recombinant identification program (RIP), the recombinant detection program (RDP5), and using the maximum-likelihood phylogenetic method, using 410 reference sequences obtained from the Los Alamos database. CRFs and URFs were identified in 11% (213/1940) of all sequenced cases. The median age at diagnosis was 38 (30−47) years, 61% originated from Israel, and 82% were male. The most common were CRF02_AG (30.5%), CRF01_AE (16.9%), and the more complex forms CRF01_AE/CRF02_AG/A3 (10.8%) and B/F1 (7%). A significant increase in their overall proportion was observed in recent years (8.1% in 2010−2012, 20.3% in 2016−2018, p < 0.001). This increase was most prominent in individuals carrying CRF02_AG (2.5% in 2010−2015, 9.8% in 2016−2018, p < 0.001). Men who have sex with men (MSM) was the most common risk group; however, those infected with the secondary recombinant CRF02_AG/A6 were mainly injecting drug users (IDUs). The most common resistance mutations were K103N (5/213, 2.3%) and E138A (18/213, 8.5%) in the reverse transcriptase. Only E138A was more frequent in the recombinants compared with the classic subtypes and was significantly associated with a specific secondary CRF, CRF02_AG/A4. We concluded that CRFs and URFs were mainly detected in Israeli-born MSM and that an increase in the overall proportion of such HIV-1 sequences could be observed in more recent years.

Identification of Hepatitis E Virus Genotypes 3 and 7 in Israel: A Public Health Concern?

BACKGROUND: Hepatitis E (HEV) is an emerging cause of viral hepatitis worldwide. Swine carrying hepatitis E genotype 3 (HEV-3) are responsible for the majority of chronic viral hepatitis cases in developed countries. Recently, genotype 7 (HEV-7), isolated from a dromedary camel in the United Arab Emirates, was also associated with chronic viral hepatitis in a transplant recipient. In Israel, chronic HEV infection has not yet been reported, although HEV seroprevalence in humans is ~10%. Camels and swine are >65% seropositive. Here we report on the isolation and characterization of HEV from local camels and swine. METHODS: Sera from camels (n = 142), feces from swine (n = 18) and blood from patients suspected of hepatitis E (n = 101) were collected during 2017-2020 and used to detect and characterize HEV sequences. RESULTS: HEV-3 isolated from local swine and the camel-derived HEV-7 sequence were highly similar to HEV-3f and HEV-7 sequences (88.2% and 86.4%, respectively) related to viral hepatitis. The deduced amino acid sequences of both isolates were also highly conserved (>98%). Two patients were HEV-RNA positive; acute HEV-1 infection could be confirmed in one of them. DISCUSSION: The absence of any reported HEV-3 and HEV-7 infection in humans remains puzzling, especially considering the reported seroprevalence rates, the similarity between HEV sequences related to chronic hepatitis and the HEV genotypes identified in swine and camels in Israel.

Epidemiology and Transmitted HIV-1 Drug Resistance among Treatment-Naïve Individuals in Israel, 2010-2018.

Despite the low prevalence of HIV-1 in Israel, continuous waves of immigration may have impacted the local epidemic. We characterized all people diagnosed with HIV-1 in Israel in 2010-2018. The demographics and clinical data of all individuals (n = 3639) newly diagnosed with HIV-1 were retrieved. Subtypes, transmitted drug-resistance mutations (TDRM), and phylogenetic relations, were determined in >50% of them. In 39.1%, HIV-1 transmission was through heterosexual contact; 34.3% were men who have sex with men (MSM); and 10.4% were people who inject drugs. Many (>65%) were immigrants. Israeli-born individuals were mostly (78.3%) MSM, whereas only 9% of those born in Sub-Saharan Africa (SSA), Eastern Europe and Central Asia (EEU/CA), were MSM. The proportion of individuals from SSA decreased through the years 2010-2018 (21.1% in 2010-2012; 16.8% in 2016-2018) whereas those from EEU/CA increased significantly (21% in 2010-2012; 27.8% in 2016-2018, p < 0.001). TDRM were identified in 12.1%; 3.7, 3.3 and 6.6% had protease inhibitors (PI), nucleotide reverse transcriptase inhibitors (NRTI), and non-nucleoside reverse transcriptase inhibitors (NNRTI) TDRM, respectively, with the overall proportion remaining stable in the studied years. None had integrase TDRM. Subtype B was present in 43.9%, subtype A in 25.2% (A6 in 22.8 and A1 in 2.4%) and subtype C in 17.1% of individuals. Most MSM had subtype B. Subtype C carriers formed small clusters (with one unexpected MSM cluster), A1 formed a cluster mainly of locally-born patients with NNRTI mutations, and A6 formed a looser cluster of individuals mainly from EEU. Israelis, <50 years old, carrying A1, had the highest risk for having TDRM. In conclusion, an increase in immigrants from EEU/CA and a decrease in those from SSA characterized the HIV-1 epidemic in 2010-2018. Baseline resistance testing should still be recommended to identify TDRM, and improve surveillance and care.

Sexual intermingling of Arab and Jewish MSM in Israel: results of a molecular epidemiology study.

OBJECTIVES: MSM comprise ∼30% of new HIV infections in Israel, a country with mixed Jewish and Arab populations. We molecularly characterized HIV-1 in the Arab and Jewish MSM (AMSM, JMSM) populations to reveal possible interethnical connections. DESIGN: Cross-sectional study. METHODS: All Israeli-born, HIV-1-infected MSM diagnosed between 2005 and 2016 (n = 1143) were cross-matched with the National Civil Registry to identify religion (Jews/Muslims/Christians). Transmitted drug-resistance mutations (TDRM) and HIV-1 subtypes were determined on the first partial protease and reverse transcriptase sequences from treatment-naive patients and phylogenetic trees were constructed. RESULTS: Among MSM, 6.4% (73/1143) were Arabs and 93.6% (1070/1143) were Jews. Interestingly, a higher proportion of Arabs was identified among non-MSM (19%, 46/247 versus 6.4%, 73/1143, P < 0.01). Subtype analysis of 62 HIV-1 AMSM and 440 randomly selected HIV-1 JMSM sequences revealed 80.6, 8.1, 4.8 and 6.5% of AMSM and 82.3, 9.5, 4.1 and 4.1% of JMSM had B, A, C and non-A/B/C, respectively. Overall, 13.1% (66/502) had TDRM; reverse transcriptase-K103N/S, M184 V, T215S and protease-L90M were the most common. TDRM prevalence was not significantly higher in JMSM compared to AMSM (P = 0.1) and no temporal changes were observed in their frequency. Phylogenetic analysis demonstrated AMSM and JMSM clusters including L90M, K103N/S or T215S TDRM. CONCLUSION: Intermingling of AMSM and JMSM HIV-1 in clusters of HIV-1 sequences suggest interethnical sexual contacts among these MSM. Interventions aiming to prevent HIV-transmission in MSM should similarly address both populations groups. The high TDRM frequency requires continuation of resistance testing.

Diagnosis of HIV-1 infection: Performance of Xpert Qual and Geenius supplemental assays in fourth generation ELISA-reactive samples.

BACKGROUND: Architect (AR) and Vidas (VD) fourth generation HIV screening immunoassays, which identify early stages of HIV infections, could have false positive results especially at low signal/cutoff (S/C) AR values. Geenius HIV1/2 (GS) is a specific confirmation line immunoassay that is not highly sensitive to early HIV infections. An HIV-1 RNA assay may better detect such infections. OBJECTIVES: To evaluate all AR-VD reactive samples with GS results, and to assess Xpert Qual HIV-1 RNA assay (XQ) as an alternative to GS, in the first low S/C AR-VD-reactive samples from a tested individual. STUDY DESIGN: First AR-VD-reactive-GS-tested results from all individuals with resolved HIV status, collected between March 2015 and March 2017 (n = 749), were retrospectively assessed. Samples with AR-VD-reactive-GS-discordant results and those with low S/C AR-VD-reactive results, were tested by XQ. Receiver operating characteristic (ROC) analysis of GS and XQ sensitivity/specificity was performed. RESULTS: Overall, 94.1% (705/749) of AR-VD-reactive results were true HIV-1 positive. All samples with <3 S/C AR values were false positive. XQ resolved all first samples with AR-VD-reactive-GS-discordant results. The diagnostic accuracy of XQ in low (≤33 S/C) AR-VD-reactive samples was better than that of GS (97.6%, 81/83 versus 73.5%, 61/83, p < 0.01). ROC analysis for low S/C AR samples was optimal for pooled XQ and GS results. CONCLUSIONS: Incorporating XQ in the current screening algorithm for the first AR-VD-reactive-GS-discordant samples may significantly reduce overall turn-around time of HIV-1 diagnosis.

Comparison between next-generation and Sanger-based sequencing for the detection of transmitted drug-resistance mutations among recently infected HIV-1 patients in Israel, 2000-2014.

INTRODUCTION: Transmitted drug-resistance mutations (TDRM) may hamper successful anti-HIV-1 therapy and impact future control of the HIV-1 epidemic. Recently infected, therapy-naïve individuals are best suited for surveillance of such TDRM. In this study, TDRM, detected by next-generation sequencing (NGS) were compared to those identified by Sanger-based population sequencing (SBS) in recently infected HIV-1 patients. METHODS: Historical samples from 80 recently infected HIV-1 patients, diagnosed between 2000 and 2014, were analysed by MiSeq (NGS) and ABI (SBS). DeepChek-HIV (ABL) was used for interpretation of the results. RESULTS: Most patients were males (80%); Men who have sex with men (MSM) was the major transmission group (58.8%). Overall, TDRM were detected in 31.3% of patients by NGS and 8.8% by SBS, with SBS TDRM restricted to persons infected with subtype B. All SBS-detected TDRM were identified by NGS. The prevalence of TDRM impacting protease inhibitors (PI), nucleoside reverse transcriptase inhibitors (NRTI) and non-nucleoside reverse transcriptase inhibitors (NNRTI) was 11.3, 26.2 7.5%, respectively, in NGS analyses and 0, 3.8 and 5%, respectively, in SBS analyses. More patients with NGS and SBS TDRM were identified in 2008-2014 (37.2% or 13.9%, respectively) compared to 2000-2007 (24.3% or 2.7%, respectively), and a significantly greater number of these patients had multiple NGS TDRM. The most abundant, albeit, minor-frequency RT TDRM, were the K65R and D67N, while K103N, M184V and T215S were high-frequency mutations. Minor TDRM did not become a major variant in later samples and did not hinder successful treatment. CONCLUSIONS: NGS can replace SBS for mutation detection and allows for the detection of low-frequency TDRM not identified by SBS. Although rates of TDRM in Israel continued to increase from 2000 to 2014, minor TDRM did not become major species. The need for ongoing surveillance of low-frequency TDRM should be revisited in a larger study.

Evaluation of Xpert HIV-1 Qual assay for resolution of HIV-1 infection in samples with negative or indeterminate Geenius HIV-1/2 results.

BACKGROUND: Diagnosis of HIV infection is a multistage algorithm. Following screening with 4(th) generation combination immunoassay, confirmation of HIV infection is performed with an antibody assay that differentiates HIV-1 from HIV-2 infection. In the newly updated algorithm, samples that are nonreactive or indeterminate in the differentiation assay are to be tested with an HIV-1 nucleic acid amplification (NAAT) test for resolution. Xpert HIV-1 Qual is a new NAAT assay approved for the identification of HIV infection in whole and dried blood. OBJECTIVES: To assess the performance of Xpert HIV-1 Qual supplementary assay in resolving the clinical status of serum samples reactive by 4(th) generation immunoassays and indeterminate or negative by Geenius HIV-1/2 confirmatory assay. STUDY DESIGN: In a retrospective study, samples from 97 individuals for whom the true HIV-1 status was already known (by follow-up samples) and which were negative or indeterminate by HIV-1/2 Geenius assay were tested with Xpert Qual HIV-1 assay. RESULTS: Xpert Qual assay correctly classified all 97 samples from HIV-1 positive (n=49) and negative (n=48) individuals. The sensitivity and specificity of Xpert Qual when using the true HIV status as a reference were 100% (92.7-100% at 95% confidence interval [CI] and 92.6-100% at 95% CI, respectively). CONCLUSIONS: Applying Xpert Qual HIV-1 assay in the new HIV multi-stage diagnostic algorithm correctly classified 100% of HIV-1 infections including 49 from HIV-1 carriers who have not yet seroconverted. With this assay the total time required for acute HIV diagnosis could be significantly reduced.