SARS-CoV-2 Test-to-Stay in Daycare.

BACKGROUND AND OBJECTIVES: Test-to-stay concepts apply serial testing of children in daycare after exposure to SARS-CoV-2 without use of quarantine. This study aims to assess the safety of a test-to-stay screening in daycare facilities. METHODS: 714 daycare facilities and approximately 50 000 children ≤6 years in Cologne, Germany participated in a SARS-CoV-2 Pool-polymerase chain reaction (PCR) screening from March 2021 to April 2022. The screening initially comprised post-exposure quarantine and was adapted to a test-to-stay approach during its course. To assess safety of the test-to-stay approach, we explored potential changes in frequencies of infections among children after the adaptation to the test-to-stay approach by applying regression discontinuity in time (RDiT) analyses. To this end, PCR-test data were linked with routinely collected data on reported infections in children and analyzed using ordinary least squares regressions. RESULTS: 219 885 Pool-PCRs and 352 305 Single-PCRs were performed. 6440 (2.93%) Pool-PCRs tested positive, and 17 208 infections in children were reported. We estimated that during a period of 30 weeks, the test-to-stay concept avoided between 7 and 20 days of quarantine per eligible daycare child. RDiT revealed a 26% reduction (Exp. Coef: 0.74, confidence interval 0.52-1.06) in infection frequency among children and indicated no significant increase attributable to the test-to-stay approach. This result was not sensitive to adjustments for 7-day incidence, season, SARS-CoV-2 variant, and socioeconomic status. CONCLUSIONS: Our analyses provide evidence that suggest safety of the test-to-stay approach compared with quarantine measures. This approach offers a promising option to avoid use of quarantine after exposure to respiratory pathogens in daycare settings.

Real-world performance of the NeuMoDx™ HCV Quant Test for quantification of hepatitis C virus (HCV)-RNA.

Quantification of hepatitis C virus (HCV)-RNA in serum or plasma samples is an essential parameter in HCV diagnostics. Here, the NeuMoDx™Molecular System (Qiagen) was tested for the most common HCV genotypes and compared to the cobas c6800 system (Roche). HCV-RNA from 131 plasma/serum samples from chronically infected patients was determined in parallel on the NeuMoDx and c6800 systems. Linearity was analysed using the four most common HCV genotypes (1-4) in our cohort. The coefficient of variation (CV) within (intra-assay) and between (inter-assay) runs was calculated based on HCV-RNA concentration. Quantitative HCV-RNA results were highly correlated on both test systems (R2 = 0.7947; y = 0.94 x + 0.37). On average, the NeuMoDx and c6800 HCV RNA levels showed a mean difference of only 0.05 log10 IU/mL but with a broad distribution (±1.2 2 x SD). The NeuMoDx demonstrated very good linearity across all HCV genotypes tested at concentrations between 1.7 and 6.2 log10 IU/mL (R2 range: 0.9257-0.9991) with the highest mean coefficient of determination for genotype 1 (R2 = 0.9909). The mean intra- and inter-assay CV for both serum and plasma samples was <5 %. The NeuMoDx HCV-RNA Assay demonstrates high subtype-independent comparability, linearity, and reproducibility for the quantification of HCV-RNA in serum and plasma samples from chronically infected patients.

Five-year single-center analysis of cytomegalovirus viremia in kidney transplant recipients and possible implication for novel prophylactic therapy approaches.

BACKGROUND: Cytomegalovirus (CMV) infections are a common complication after kidney transplantation (KTx) and negatively affecting patient outcome. Valganciclovir (VGC) prophylaxis is often limited by drug-induced side effects and dose reduction due to decline in kidney function. METHOD: In the present study, episodes of CMV viremia in the first year after KTx in a cohort of 316 recipients were analyzed retrospectively to identify risk factors linked to persistent infections. RESULTS: In the studied cohort, 18.7% of patients showed a high-risk (HR) constellation (D+/R-) for CMV infections. CMV viremia affected 22% of our cohort, with HR patients being the most affected cohort (44.1%). Within this group, most viremic events (65.3%) occurred while patients were still on prophylactic therapy, showing significantly higher viral loads and a longer duration compared to seropositive recipients. CONCLUSION: The analysis at hand revealed that detection of viremia under ongoing antiviral prophylaxis bears an increased risk for sustained viral replication and antiviral drug resistance in HR patients. We identified low estimated glomerular filtration rate (eGFR) and lower dose VGC prophylaxis post-KTx as a risk factor for breakthrough infections in HR patients in our single center cohort. These patients might benefit from a closer CMV monitoring or novel prophylactic agents as letermovir.

Torque Teno Virus load is associated with CDC stage and CD4+ cell count in people living with HIV but unrelated to AIDS-defining events and Human Pegivirus load.

BACKGROUND: Torque Teno Virus (TTV) is a non-enveloped, circular single-strand DNA virus and part of the human virome. The replication of TTV was related to the immune status in patients treated with immunosuppressive drugs after organ transplantation. We hypothesize that TTV load could be an additional marker for immune function in people living with HIV (PLWH). METHODS: In this analysis serum samples of PLWH from the RESINA multicenter cohort were reanalysed for TTV. Investigated clinical and epidemiological parameters included Pegivirus (HPgV) load, age, sex, HIV load, CD4+ cell count (CDC 1, 2, 3) and CDC clinical stages (1993 CDC classification system, A, B, C) before initiation of antiretroviral treatment. Regression analysis was used to detect possible associations among parameters. RESULTS: Our analysis confirmed TTV as a strong predictor of CD4+ cell count and CDC class 3. This relationship was used to propose a first classification of TTV load in regard to clinical stage. We found no association with clinical CDC stages A, B and C. HPgV load was inversely correlated with HIV load but not TTV load. CONCLUSIONS: TTV load was associated with immunodeficiency in PLWH. Neither TTV- nor HIV load were predictive for the clinical categories of HIV infection.

Dynamics and durability of HIV-1 neutralization are determined by viral replication.

Human immunodeficiency virus type 1 (HIV-1)-neutralizing antibodies (nAbs) that prevent infection are the main goal of HIV vaccine discovery. But as no nAb-eliciting vaccines are yet available, only data from HIV-1 neutralizers-persons with HIV-1 who naturally develop broad and potent nAbs-can inform about the dynamics and durability of nAb responses in humans, knowledge which is crucial for the design of future HIV-1 vaccine regimens. To address this, we assessed HIV-1-neutralizing immunoglobulin G (IgG) from 2,354 persons with HIV-1 on or off antiretroviral therapy (ART). Infection with non-clade B viruses, CD4+ T cell counts <200 µl-1, being off ART and a longer time off ART were independent predictors of a more potent and broad neutralization. In longitudinal analyses, we found nAb half-lives of 9.3 and 16.9 years in individuals with no- or low-level viremia, respectively, and 4.0 years in persons who newly initiated ART. Finally, in a potent HIV-1 neutralizer, we identified lower fractions of serum nAbs and of nAb-encoding memory B cells after ART initiation, suggesting that a decreasing neutralizing serum activity after antigen withdrawal is due to lower levels of nAbs. These results collectively show that HIV-1-neutralizing responses can persist for several years, even at low antigen levels, suggesting that an HIV-1 vaccine may elicit a durable nAb response.

Torque teno virus-DNA load as individual cytomegalovirus risk assessment parameter upon allogeneic hematopoietic stem cell transplantation.

BACKGROUND: Immune recovery following allogeneic hematopoietic stem cell transplantation (allo-HSCT) decisively influences the occurrence of opportunistic infections, one of the leading causes of death among this group of patients. Yet, today, there are no laboratory parameters mirroring immune function sufficiently. Torque teno virus (TTV) has already proven itself as a functional immune marker in other settings. AIMS: In this analysis, we investigated whether monitoring of TTV-DNA load in whole blood is able to provide additional information on the capacity of the immune system to control cytomegalovirus (CMV) replication in allo-HSCT recipients. METHODS: Whole blood samples from 59 patients were collected upon allo-HSCT (between Day -7 and +10), on Day +14, +21, +28, +56, +90, and +365 post-transplant. TTV-DNA loads and other relevant clinical information were correlated with the risk of CMV infections or reactivations, defined by evidence of viral replication in blood. RESULTS: CMV serostatus of the recipient and a TTV load below 1000 copies/mL upon allo-HSCT were significantly associated with an increased incidence of CMV infection or reactivation. CONCLUSIONS: Quantification of TTV load in the early phase of allo-HSCT procedure could provide additional information in order to identify patients at risk for CMV infection or reactivation.

Acute orchitis deciphered: Coxsackievirus B strains are the main etiology and their presence in semen is associated with acute inflammation and risk of persistent oligozoospermia.

Although various viruses are considered to be the clinical cause for acute orchitis, it is completely unclear to what extent and which viruses are etiologically involved in acute orchitis and what the clinic and course of these patients are like. Therefore, a prospective study was set up to decipher acute isolated orchitis. Between July 2007 and February 2023, a total of 26 patients with isolated orchitis were recruited and compared with 530 patients with acute epididymitis. We were able to show for isolated orchitis, that (1) orchitis is usually of viral origin (20/26, 77%) and enteroviruses with coxsackievirus B strains (16/26, 62%) are predominant, (2) virus isolates could be received from semen indicating the presence of replication-competent virus particles, (3) a polymerase chain reaction (PCR) for enteroviruses should be conducted using semen provided at the onset of disease, because the virus is not detectable in serum/urine, (4) there is a circannual occurrence with the maximum in summer, (5) orchitis is associated with a characteristic inflammatory cytokine panel in the semen and systemic inflammation, (6) orchitis is usually rapidly self-limiting, and (7) about 30% of patients (6/20) suffer ongoing oligozoospermia. These seven emerging aspects are likely to fundamentally change thinking and clinical practice regarding acute isolated orchitis.

Optimizing Antiretroviral Therapy in Heavily ART-Experienced Patients with Multi-Class Resistant HIV-1 Using Proviral DNA Genotypic Resistance Testing.

Resistance to multiple antiretroviral drugs among people living with HIV (PLWH) can result in a high pill burden, causing toxicity and drug interactions. Thus, the goal is to simplify treatment regimens while maintaining effectiveness. However, former resistance analysis data may not be current or complete. The use of proviral DNA genotyping may assist in selecting appropriate treatment options. A retrospective study was carried out on individuals belonging to the Cologne HIV cohort with a resistance history to two or more antiretroviral (ARV) classes and on non-standard antiretroviral therapy (ART). Patients required former viral RNA and a recent proviral DNA resistance test to be available prior to the switch to ART. Potential discrepancies between resistance test results obtained through RNA and proviral DNA methods and the consequent virological and clinical outcomes following ART adjustments were analyzed. Out of 1250 patients, 35 were eligible for inclusion in this study. The median length of known HIV infection was 27 years, and the median duration of ART was 22 years. Of the 35 participants, 16 had received all five ARV classes. Based on proviral DNA genotyping results, ART was simplified in 17 patients. At the last follow-up examination after changing therapy, 15 patients had HIV RNA <50 copies/mL (median 202 days, range 21-636). The mean number of pills per day decreased from eight to three, and the median intake frequency decreased from two to one time/day (ranges 1-2). Our study supports the use of proviral DNA genotyping as a safe strategy for switching to simplified ART regimens. However, the lack of extensive research on the advantages of proviral DNA genotyping makes it challenging to fully assess its benefits in terms of treatment selection.

Ex Vivo Immune Responsiveness to SARS-CoV-2 Omicron BA.5.1 Following Vaccination with Unmodified mRNA-Vaccine.

(1) Background: The high incidence of SARS-CoV-2 infection in vaccinated persons underscores the importance of individualized re-vaccination. PanIg antibodies that act against the S1/-receptor binding domain quantified in serum by a routine diagnostic test (ECLIA, Roche) can be used to gauge the individual ex vivo capacity of SARS-CoV-2 neutralization. However, that test is not adapted to mutations in the S1/-receptor binding domain, having accumulated in SARS-CoV-2 variants. Therefore, it might be unsuited to determine immune-reactivity against SARS-CoV-2 BA.5.1. (2) Method: To address this concern, we re-investigated sera obtained six months after second vaccinations with un-adapted mRNA vaccine Spikevax (Moderna). We related serum levels of panIg against the S1/-receptor binding domain quantified by the un-adapted ECLIA with full virus neutralization capacity against SARS-CoV-2 B.1 or SARS-CoV-2 BA5.1. (3) Results: 92% of the sera exhibited sufficient neutralization capacity against the B.1 strain. Only 20% of the sera sufficiently inhibited the BA5.1 strain. Sera inhibiting BA5.1 could not be distinguished from non-inhibiting sera by serum levels of panIg against the S1/-receptor binding domain quantified by the un-adapted ECLIA. (4) Conclusion: Quantitative serological tests for an antibody against the S1/-receptor binding domain are unsuited as vaccination companion diagnostics, unless they are regularly adapted to mutations that have accumulated in that domain.

CMV-IgG pre-allogeneic hematopoietic stem cell transplantation and the risk for CMV reactivation and mortality.

Cytomegalovirus (CMV) represents one of the most common infectious complications after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Currently, a common diagnostic test used to stratify the risk for CMV infection in allo-HSCT recipients is the qualitative CMV serology of donor and recipient. A positive serostatus of the recipient is the most important risk factor for CMV reactivation and associated with reduced overall survival post-transplantation (TX). Direct and indirect effects of CMV are involved in the poorer survival outcome. The present study investigated if the quantitative interpretation of anti-CMV IgG before allo-HSCT might serve as a novel parameter for the identification of patients at risk for CMV reactivation and worse outcome post-TX. For this purpose, a cohort of 440 allo-HSCT recipients over a period of 10 years was retrospectively analyzed. Our findings indicated that patients with high CMV IgG pre-allo-HSCT had a higher risk to develop CMV reactivation, including clinically relevant infections, and a worse prognosis 36 months post-allo-HSCT as compared to recipients with low CMV IgG values. In the letermovir (LMV) era, this group of patients might benefit from a closer CMV monitoring, and hence, earlier intervention if needed, especially after discontinuation of prophylaxis.

Immune response to mRNA-based COVID-19 booster vaccination in people living with HIV.

OBJECTIVES: Our objective was to assess immune responses and their influencing factors in people living with HIV after messenger RNA (mRNA)-based COVID-19 booster vaccination (third dose). METHODS: This was a retrospective cohort study of people living with HIV who received booster vaccination with BNT-162b2 or mRNA-1273 between October 2021 and January 2022. We assessed anti-spike receptor-binding domain (RBD) immunoglobulin G (IgG), virus neutralizing activity (VNA) titres reported as 100% inhibitory dilution (ID100 ), and T-cell response (using interferon-gamma-release-assay [IGRA]) at baseline and quarterly follow-up visits. Patients with reported COVID-19 during follow-up were excluded. Predictors of serological immune response were analyzed using multivariate regression models. RESULTS: Of 84 people living with HIV who received an mRNA-based booster vaccination, 76 were eligible for analysis. Participants were on effective antiretroviral therapy (ART) and had a median of 670 CD4+ cells/µL (interquartile range [IQR] 540-850). Following booster vaccination, median anti-spike RBD IgG increased by 705.2 binding antibody units per millilitre (BAU/mL) and median VNA titres increased by 1000 ID100 at the follow-up assessment (median 13 weeks later). Multivariate regression revealed that time since second vaccination was a predictor of stronger serological responses (p < 0.0001). No association was found for other factors, including CD4+ status, choice of mRNA vaccine, or concomitant influenza vaccination. In total, 45 patients (59%) had a reactive baseline IGRA, of whom two lost reactivity during follow-up. Of 31 patients (41%) with non-reactive baseline IGRA, 17 (55%) converted to reactive and seven (23%) remained unchanged following booster vaccination. CONCLUSIONS: People living with HIV with ≥500 CD4+ cells/µL showed favourable immune responses to mRNA-based COVID-19 booster vaccination. A longer time (up to 29 weeks) since second vaccination was associated with higher serological responses, whereas choice of mRNA vaccine or concomitant influenza vaccination had no impact.

In-depth virological and immunological characterization of HIV-1 cure after CCR5Δ32/Δ32 allogeneic hematopoietic stem cell transplantation.

Despite scientific evidence originating from two patients published to date that CCR5Δ32/Δ32 hematopoietic stem cell transplantation (HSCT) can cure human immunodeficiency virus type 1 (HIV-1), the knowledge of immunological and virological correlates of cure is limited. Here we characterize a case of long-term HIV-1 remission of a 53-year-old male who was carefully monitored for more than 9 years after allogeneic CCR5Δ32/Δ32 HSCT performed for acute myeloid leukemia. Despite sporadic traces of HIV-1 DNA detected by droplet digital PCR and in situ hybridization assays in peripheral T cell subsets and tissue-derived samples, repeated ex vivo quantitative and in vivo outgrowth assays in humanized mice did not reveal replication-competent virus. Low levels of immune activation and waning HIV-1-specific humoral and cellular immune responses indicated a lack of ongoing antigen production. Four years after analytical treatment interruption, the absence of a viral rebound and the lack of immunological correlates of HIV-1 antigen persistence are strong evidence for HIV-1 cure after CCR5Δ32/Δ32 HSCT.

Humoral immune response and live-virus neutralization of the SARS-CoV-2 omicron (BA.1) variant after COVID-19 mRNA vaccination in children and young adults with chronic kidney disease.

BACKGROUND: Data on humoral immune response to standard COVID-19 vaccination are scarce in adolescent patients and lacking for children below 12 years of age with chronic kidney disease including kidney transplant recipients. METHODS: We therefore investigated in this retrospective two-center study (DRKS00024668; registered 23.03.2021) the humoral immune response to a standard two-dose mRNA vaccine regimen in 123 CKD patients aged 5-30 years. A live-virus assay was used to assess the serum neutralizing activity against the SARS-CoV-2 omicron (BA.1) variant. RESULTS: Children aged 5-11 years had a comparable rate and degree of immune response to adolescents despite lower vaccine doses (10 µg vs. 30 µg BNT162b2). Treatment with two (odds ratio 9.24) or three or more (odds ratio 17.07) immunosuppressants was an independent risk factor for nonresponse. The immune response differed significantly among three patient cohorts: 48 of 77 (62.3%) kidney transplant recipients, 21 of 26 (80.8%) patients on immunosuppressive therapy, and 19 of 20 (95.0%) patients with chronic kidney disease without immunosuppressive therapy responded. In the kidney transplant recipients, immunosuppressive regimens comprising mycophenolate mofetil, an eGFR of < 60 mL/min/1.73 m2, and female sex were independent risk factors for nonresponse. Two of 18 (11.1%) and 8 of 16 (50.0%) patients with an anti-S1-RBD IgG of 100-1411 and > 1411 BAU/mL, respectively, showed a neutralization activity against the omicron variant. CONCLUSION: A standard mRNA vaccine regimen in immunosuppressed children and adolescents with kidney disease elicits an attenuated humoral immune response with effective live virus neutralization against the omicron variant in approximately 10% of the patients, underlying the need for omicron-adapted vaccination. A higher resolution version of the Graphical abstract is available as Supplementary information.

Implementing the Lolli-Method and pooled RT-qPCR testing for SARS-CoV-2 surveillance in schools: a pilot project.

PURPOSE: School closures have been used as part of lockdown strategies to contain the spread of SARS-CoV-2, adversely affecting children's health and education. To ensure the accessibility of educational institutions without exposing society to the risk of increased transmissions, it is essential to establish SARS-CoV-2 testing strategies that are child-friendly, scalable and implementable in a daily school routine. Self-sampling using non-invasive saliva swabs combined with pooled RT-qPCR testing (Lolli-Method) has been proven to be a sensitive method for the detection of SARS-CoV-2. METHODS: We conducted a pilot project in Cologne, Germany, designed to determine the feasibility of a large-scale rollout of the Lolli-Method for testing without any additional on-site medical staff in schools. Over a period of three weeks, students from 22 schools were sampled using the Lolli-Method. At the end of the project, teachers were asked to evaluate the overall acceptance of the project. RESULTS: We analyzed a total of 757 pooled RT-qPCRs obtained from 8,287 individual swabs and detected 7 SARS-CoV-2 infected individuals. The Lolli-Method was shown to be a feasible and accepted testing strategy whose application is only slightly disruptive to the daily school routine. CONCLUSION: Our observations suggest that the Lolli-Method in combination with pooled RT-qPCR can be implemented for SARS-CoV-2 surveillance in daily school routine, applicable on a large scale.