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Keywords = SARS-CoV-2 PCR testing

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27 pages, 7607 KB  
Article
A Portable, Foldable Negative-Pressure Aerosol-Containment System (FNPACS) for Aerosol Control During Aerosol-Generating Procedures
by Bing Rui Huang, Fatimah Ibrahim, Ina Ismiarti Shariffuddin, Puteri Ainaa S. Ibrahim, Li-Yen Chang, Karunan Joseph, Mas Sahidayana Mohktar and Noorjahan Haneem Md Hashim
Bioengineering 2026, 13(6), 669; https://doi.org/10.3390/bioengineering13060669 - 9 Jun 2026
Viewed by 352
Abstract
Aerosol-generating procedures (AGPs) expose healthcare personnel to airborne pathogens and require portable engineering controls that can be integrated into routine clinical workflows. We developed a portable, foldable negative-pressure aerosol-containment system (FNPACS) combining adaptive fan control, an H14 high-efficiency particulate air (HEPA) filter, and [...] Read more.
Aerosol-generating procedures (AGPs) expose healthcare personnel to airborne pathogens and require portable engineering controls that can be integrated into routine clinical workflows. We developed a portable, foldable negative-pressure aerosol-containment system (FNPACS) combining adaptive fan control, an H14 high-efficiency particulate air (HEPA) filter, and a disposable metal-oxide prefilter in a mobile filtration module. Bench performance was evaluated using pressure-flow testing in accordance with National Environmental Balancing Bureau (NEBB) procedures and International Organization for Standardization (ISO) 14644-3, polyalphaolefin aerosol challenge testing, and smoke visualization, while an exploratory clinical study assessed environmental contamination via real-time reverse-transcription PCR (rRT-PCR) in 11 patients (31 assay analyses). Bench testing demonstrated HEPA filtration efficiencies of 99.994–99.997%, stable negative-pressure generation across fan duty cycles, no detectable downstream breakthrough beyond the HEPA filter under the tested conditions, and effective inward airflow on smoke testing. A Lagrangian discrete phase model (DPM) particle-tracking simulation further characterized size-dependent aerosol-surrogate transport. Under HEPA-ON active-extraction conditions, 73.0–86.1% of simulated 0.3–10 µm water-equivalent particles were transported to the HEPA suction pathway, while 13.9–27.0% were deposited on internal wall surfaces. In the clinical evaluation, SARS-CoV-2 RNA detection on environmental swabs was limited and predominantly low level. The clearest reproducible signal occurred on the top interior surface under HEPA-OFF conditions, whereas HEPA-ON detections were isolated or presumptive high-Ct signals without reproducible confirmation. These findings provide preliminary engineering and usability support for FNPACS as a feasible near-source aerosol-control platform for AGPs. The patient swab component should be interpreted as an exploratory, proof-of-concept assessment rather than confirmatory evidence of clinical containment efficiency because several clinical cases had non-supportive patient-related controls and were therefore not used in the primary containment interpretation. Full article
(This article belongs to the Section Biomedical Engineering and Biomaterials)
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16 pages, 575 KB  
Article
Population-Specific Exploration of MIR146A Gene Polymorphism in Acute Renal Rejection: A Cross-Sectional, Case–Control Study
by Nor Elhouda Nacer, Soumia Missoum, Houssem Eddine Ouarhlent, Seddam Hares, Asma Ribouh and Ghania Belaaloui
Int. J. Mol. Sci. 2026, 27(11), 5105; https://doi.org/10.3390/ijms27115105 - 4 Jun 2026
Viewed by 432
Abstract
Acute renal allograft rejection (AR) is immune-mediated. Recent evidence highlights some microRNAs as immune modulators. Few and conflicting studies have studied the impact of the MIR146A gene single-nucleotide polymorphism rs2910164 (C>G) on AR. We explored the association of rs2910164 with AR in a [...] Read more.
Acute renal allograft rejection (AR) is immune-mediated. Recent evidence highlights some microRNAs as immune modulators. Few and conflicting studies have studied the impact of the MIR146A gene single-nucleotide polymorphism rs2910164 (C>G) on AR. We explored the association of rs2910164 with AR in a single-center cohort of 533 kidney transplant recipients (KTRs) by genotyping cases with biopsy-proven late AR (AR group, n = 35) and matched control KTRs without AR (non-AR group, n = 60). Genotyping was performed with real-time PCR. Multivariable logistic regression and Firth penalized logistic regression, as a sensitivity analysis, were used to adjust for confounding factors. Donor–recipient age difference was significantly higher in the AR group than in the non-AR group (23.37 ± 11.29 vs. 14.83 ± 10.54, p < 0.001). Recipient mean age in the AR group is lower than in the non-AR group (27.51 ± 10.34 vs. 32.83 ± 9.76 years, p = 0.014), while the opposite is observed with the donor mean age (49.57 ± 10.37 vs. 43.27 ± 10.27 years, p = 0.005). AR was associated with preformed donor-specific antibodies (DSAs) (45.7% vs. 8.3%, p = 0.000, OR = 9.263, 95% CI (2.988–28.720)), and with two HLA-A* mismatches (17.1% vs. 3.3%, p = 0.048, OR = 6.000, 95% CI (1.139–31.595)). Moreover, post-transplant viral infections, particularly with CMV and SARS-CoV-2, were associated with AR (p < 0.05). However, rs2910164 was not associated with AR across all the tested genetic models (p > 0.05). Our study provides population-specific negative association data on rs2910164 and AR. Larger multicentric studies and future meta-analyses are needed to clarify whether any effect is modest or context-dependent. Full article
(This article belongs to the Special Issue Advances in Kidney Transplantation)
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16 pages, 1022 KB  
Article
Repurposing Candidate Drugs to Prevent SARS-CoV-2: A PharmLines Test-Negative Case–Control Study
by Guiling Zhou, Nina Dael, Stefan Verweij, Spyros Balafas, Sumaira Mubarik, Jens Bos, Anna Maria Gerdina Pasmooij, Debbie van Baarle, Peter G. M. Mol, Geertruida H. de Bock, Eelko Hak and Lifelines Corona Research Initiative
Pharmaceuticals 2026, 19(6), 861; https://doi.org/10.3390/ph19060861 - 29 May 2026
Viewed by 255
Abstract
Background: The rapid emergence of immune-evasive SARS-CoV-2 variants necessitates the identification of accessible, low-cost prophylactic strategies. While drug repurposing offers a time-efficient alternative to novel drug development, clinical evidence for existing medications in the general population remains limited. The PharmLines Initiative provided us [...] Read more.
Background: The rapid emergence of immune-evasive SARS-CoV-2 variants necessitates the identification of accessible, low-cost prophylactic strategies. While drug repurposing offers a time-efficient alternative to novel drug development, clinical evidence for existing medications in the general population remains limited. The PharmLines Initiative provided us with unique data linkage for this study to assess the associations between 42 candidate drugs and COVID-19 infection. Potential effect modification by dominant SARS-CoV-2 strain and COVID-19 vaccination status was addressed. Methods: We conducted a test-negative case–control study using data from the Lifelines cohort and University of Groningen IADB.nl dispensing database. Cases were adults with self-reported reverse transcription polymerase chain reaction (RT-PCR) test results for SARS-CoV-2 and controls had only negative results. Cases and controls were matched in age, sex, and testing date. The 42 candidate drugs were identified through a systematic review of prior publications. The primary outcome was SARS-CoV-2 infection. We applied multivariable conditional logistic regression to estimate the associations, with subgroup analyses for variant and vaccination effects. Significance levels were corrected for multiple testing. Results: From November 2020 to October 2022, we included 2019 test-positive cases and 4089 matched test-negative controls with a mean age of 57 years and 67% female. After adjustments for confounders, none of the studied drugs were associated with SARS-CoV-2 infection. When stratified by SARS-CoV-2 variants, chronic use of calcium channel blockers (adjusted odds ratio 2.13; 95% CI 1.45–3.13), diuretics (2.23; 95% CI 1.50–3.32), and metformin (4.31; 95% CI 1.91–9.69) were associated with increased risks of original strain SARS-CoV-2 infection. No significant associations were found in the vaccination status subgroup analysis. Conclusions: Despite limited statistical power for some drugs, none of the studied drugs showed protective associations against SARS-CoV-2 infection. Antihypertensives and metformin were associated with increased risk. These findings do not support the off-label use of these drugs as COVID-19 prophylaxis in the general population. Full article
(This article belongs to the Section Pharmacology)
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7 pages, 1200 KB  
Case Report
Severe Mycoplasma pneumoniae Pneumonia During the 2023–2024 European Re-Emergence: Why Severity Does Not Predict Macrolide Resistance
by Enrico Perugini, Ludovica Ferrari, Marco Iannetta, Barbara Bartolini, Valentina Dimartino, Marco Favaro, Carla Fontana and Loredana Sarmati
Antibiotics 2026, 15(5), 524; https://doi.org/10.3390/antibiotics15050524 - 21 May 2026
Viewed by 297
Abstract
Background: Following a significant decline during the 2020–2021 SARS-CoV-2 pandemic, Mycoplasma pneumoniae (MP) experienced a resurgence across Europe in 2023–2024. Although macrolide-resistant MP has increased globally, severe disease can occur even in the absence of resistance, which highlights the importance of rapid molecular [...] Read more.
Background: Following a significant decline during the 2020–2021 SARS-CoV-2 pandemic, Mycoplasma pneumoniae (MP) experienced a resurgence across Europe in 2023–2024. Although macrolide-resistant MP has increased globally, severe disease can occur even in the absence of resistance, which highlights the importance of rapid molecular characterization for clinical purposes. In this context, clinical severity is often improperly used as a surrogate marker of macrolide resistance, potentially driving unnecessary antibiotic escalation. Methods: We report a severe MP pneumonia occurring during the 2023–2024 resurgence and evaluate macrolide resistance through a rapid two-step workflow (Real Time-PCR screening for A2063G/A2064G followed by confirmatory 23S rRNA sequencing), to assess whether severity predicts resistance and to support antibiotic stewardship. Results: The patient developed acute hypoxic respiratory failure (PaO2 54.9 mmHg; P/F ratio 110), extensive centrilobular micronodules on chest CT imaging, significant systemic inflammation and elevated liver enzymes. Respiratory support was escalated from a Venturi mask to a high-flow nasal cannula and BiPAP. MP infection was confirmed by multiplex Real Time-PCR (RT-PCR) and supported by positive IgM/IgG serology. RT-PCR targeting A2063G/A2064G mutations revealed no resistance-associated variants, and Sanger sequencing of an 807 bp 23S rRNA fragment confirmed a wild-type genotype. Despite severe hypoxemic respiratory failure, no resistance-associated variants were detected, documenting a clear severity–genotype mismatch. Clinical and radiological improvement followed second-line antibiotic therapy. Conclusions: Severe MP pneumonia can occur despite the absence of macrolide resistance. During MP re-emergence, clinical severity should not be used to infer macrolide resistance. Integrating nucleic acid amplification test (NAAT) diagnosis with rapid genotyping/confirmatory 23S rRNA sequencing can prevent misclassification, reduce unwarranted broad-spectrum escalation, and strengthen antimicrobial stewardship decisions. Full article
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17 pages, 1338 KB  
Article
Comparative Performance Analysis of Commercial SARS-CoV-2 RNA Detection Assays: Implications for Sensitivity, Specificity, Accuracy, and Diagnostic Response Time
by Adriana Guimarães dos Santos, José Rodrigo Santos Silva, Maria Luísa Rodrigues Nolasco and Marcus Vinicius de Aragão Batista
Diagnostics 2026, 16(10), 1554; https://doi.org/10.3390/diagnostics16101554 - 20 May 2026
Viewed by 224
Abstract
Background/Objectives: In 2020, the world found itself in the midst of the SARS-CoV-2 pandemic. The virus has spread globally, resulting in over 779 million cases worldwide. In response to this crisis, there arose a critical need for diagnostic techniques capable of meeting the [...] Read more.
Background/Objectives: In 2020, the world found itself in the midst of the SARS-CoV-2 pandemic. The virus has spread globally, resulting in over 779 million cases worldwide. In response to this crisis, there arose a critical need for diagnostic techniques capable of meeting the overwhelming global demand, including RT-qPCR as the gold standard due to its high sensitivity and specificity. However, RT-qPCR has its limitations, including susceptibility to factors such as inadequate sample collection, variations in viral load, and insufficient clinical validation, all of which can lead to false negatives. Consequently, this study aims to evaluate the clinical performance of four commercial RT-qPCR kits for detecting SARS-CoV-2. Methods: The study utilized 200 nasopharyngeal swab samples collected in January 2022, comparing kits from Qiagen, Seegene, Bio-Manguinhos, and IBMP. Results: Results indicated significant differences in kit performance, with 66% of samples showing consistent results across all kits, and 34% showing discrepancies. Ct values were also analyzed, and statistical tests highlighted varying sensitivities among the kits, ranging from 100% to 86.82%. Conclusions: The study underscores how extraction and purification processes, kit quality, and target gene adequacy critically influence kit performance, influencing the occurrence of false positives and negatives. Full article
(This article belongs to the Special Issue Advances in Laboratory Analysis and Diagnostics)
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12 pages, 2111 KB  
Case Report
Successful Management of Severe COVID-19 in a Kidney Transplant Recipient Safe Co-Administered Tacrolimus and Ensitrelvir: A Case Report
by Noriko Miyagawa, Satoshi Yamanouchi, Hideaki Fujimoto, Eichi Uchikanezaki, Yoshinobu Kameyama, Yugo Ashino and Toshio Hattori
Reports 2026, 9(2), 159; https://doi.org/10.3390/reports9020159 - 19 May 2026
Viewed by 464
Abstract
Background and Clinical Significance: COVID-19 may worsen in patients receiving immunosuppressants. Furthermore, drug–drug interactions and concomitant use of anti-inflammatory drugs complicate treatment. We report the clinical course of severe COVID-19 pneumonia in a 74-year-old Japanese male kidney transplant recipient. Case Presentation: [...] Read more.
Background and Clinical Significance: COVID-19 may worsen in patients receiving immunosuppressants. Furthermore, drug–drug interactions and concomitant use of anti-inflammatory drugs complicate treatment. We report the clinical course of severe COVID-19 pneumonia in a 74-year-old Japanese male kidney transplant recipient. Case Presentation: The patient had been taking tacrolimus (TAC) (2.5 mg/day), mycophenolate mofetil (1000 mg/day), and prednisone (5 mg/day) since his kidney transplant 7 years earlier. Twenty days before admission, he tested positive for SARS-CoV-2 antigen and was administered molnupiravir for 5 days. At admission, real-time PCR testing of a nasopharyngeal specimen revealed high viral loads, with Ct values of 22.2 and 27.9 for the E and N2 genes, respectively. An oxygen flow rate of 15 L/min was required to maintain arterial oxygen saturation above 90%. TAC was continued, and antibiotics, steroids, anti-interleukin-6 receptor antibodies, intravenous immunoglobulin, and ensitrelvir (ESV) were administered. With invasive positive-pressure ventilation, positive end-expiratory pressure (PEEP), and prone positioning, the arterial oxygen tension/inspired oxygen tension (P/F) improved from 61.3 to 386 within 7 h. The patient was extubated 30 h after admission. The TAC dose was adjusted from 2.5 mg/day to 1 mg/day to achieve the target trough level. The patient was discharged on hospital day 8. PCR testing at discharge showed a decrease in viral load. Conclusions: This study provides insights into the treatment of COVID-19 in patients receiving immunosuppressants. Combination therapy of ESV and TAC was feasible in kidney transplant recipients with dose adjustment. The use of other anti-inflammatory drugs should also be considered. Full article
(This article belongs to the Section Infectious Diseases)
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12 pages, 1454 KB  
Article
Association of ACE I/D and TNF-α-308 Polymorphisms with COVID-19 Severity in a Mexican Population
by Mayela del Ángel-Martínez, Mauricio Salinas-Santander, Michelle Giovanna Santoyo-Suárez, Lesly González-Flores, Omar Reyes-Torres and Antonio Morlett-Chávez
BioChem 2026, 6(2), 11; https://doi.org/10.3390/biochem6020011 - 18 May 2026
Viewed by 293
Abstract
Background: COVID-19 severity shows marked interindividual variability, suggesting a role for host genetic factors. Polymorphisms in genes involved in the renin–angiotensin system and inflammatory response, such as the angiotensin-converting enzyme (ACE) and the tumor necrosis factor-alpha (TNF-α), have been proposed as potential [...] Read more.
Background: COVID-19 severity shows marked interindividual variability, suggesting a role for host genetic factors. Polymorphisms in genes involved in the renin–angiotensin system and inflammatory response, such as the angiotensin-converting enzyme (ACE) and the tumor necrosis factor-alpha (TNF-α), have been proposed as potential modulators of disease severity. Objectives: To evaluate the association between the ACE I/D (rs4646994) and TNF-α-308 G/A (rs1800629) polymorphisms and COVID-19 severity in a Mexican population. Methods: A total of 235 individuals with RT-PCR–confirmed SARS-CoV-2 infection were included. Patients were classified as hospitalized (severe, n = 155) or non-hospitalized (asymptomatic–mild, n = 80). Genotyping was performed by PCR–RFLP. Genotype distributions were analyzed using χ2 tests under dominant and recessive genetic models, and odds ratios (ORs) with 95% confidence intervals (CIs) were calculated. Results: The ACE I/D polymorphism showed a significant association with COVID-19 severity. Carriers of the I allele (ID + II) had a higher risk of hospitalization compared with DD homozygotes (OR = 2.78, 95% CI: 1.53–5.06, p = 0.001). After adjustment for sex, the association remained significant (adjusted OR = 2.55, 95% CI: 1.38–4.70, p = 0.003). Sex-stratified analysis revealed that this association was significant only in male patients. The DD genotype was more frequent among non-hospitalized individuals, suggesting a potential protective effect in this population. No significant association was observed between the TNF-α-308 G/A polymorphism. Conclusions: The ACE I/D polymorphism is associated with COVID-19 severity in a Mexican population, with a stronger association observed in males. These findings highlight the potential role of host genetic background and sex-specific effects in COVID-19 outcomes. Full article
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11 pages, 662 KB  
Article
COVID-19 and Radiological Progression of Multiple Sclerosis
by Hien Quang Nguyen, Roham Hadidchi, Anna Eligulashvili, Shounak Nandi, Aditi Vichare, Bhakti Patel, Jimmy Sanchez, Joseph Bisulca, Sonya Henry, Jimmy S. Lee and Tim Q. Duong
Diagnostics 2026, 16(10), 1513; https://doi.org/10.3390/diagnostics16101513 - 16 May 2026
Viewed by 333
Abstract
Background/Objectives: SARS-CoV-2 infection may exacerbate neuroinflammation in patients with multiple sclerosis (MS) and thus accelerate MS progression. Previous studies have reported an increased risk of disability and lesion burden among those infected with SARS-CoV-2 while others reported no differences compared to COVID− [...] Read more.
Background/Objectives: SARS-CoV-2 infection may exacerbate neuroinflammation in patients with multiple sclerosis (MS) and thus accelerate MS progression. Previous studies have reported an increased risk of disability and lesion burden among those infected with SARS-CoV-2 while others reported no differences compared to COVID− controls. We aimed to determine whether COVID-19 is associated with accelerated radiological progression of MS. Methods: This single-center, retrospective longitudinal study included patients with pre-existing relapsing-remitting MS. We identified 34 SARS-CoV-2–positive MS patients (COVID+) who had at least one brain MRI prior to, and one after, their first positive PCR test. These patients were matched 2:1 by index date to 67 SARS-CoV-2–negative MS patients (COVID−). Baseline demographics and comorbidities were comparable between groups. Two radiologists independently scored pre- and post-index MRIs for new or enlarging T2 lesions, T1 gadolinium-enhancing lesions, and parenchymal brain volume loss. Logistic regression analyses evaluated group differences, adjusting for demographic and clinical covariates. Results: Across an average imaging interval of approximately two years, no significant differences were observed between COVID+ and COVID− patients in new lesions (8.8% vs. 9.0%), enlarging lesions (2.9% vs. 6.0%), T1-enhancing lesions (5.9% vs. 1.5%), or brain volume loss (35.3% vs. 47.8%; all p > 0.05). Conclusions: There was no detectable association between SARS-CoV-2 infection and accelerated radiological progression in patients with MS over an average two-year follow-up. Longer-term investigations are warranted to clarify whether certain subgroups or more severe COVID-19 cases might be at heightened risk. Full article
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20 pages, 949 KB  
Article
Symptom Trajectories and Long-Term Sequelae of COVID-19: A Matched Case–Control Study with Population-Based Controls
by Sebastian Sołomacha, Maciej Alimowski, Anna Moniuszko-Malinowska, Łukasz Kiszkiel, Piotr Laskowski, Marlena Dubatówka, Paweł Sowa and Karol Kamiński
J. Clin. Med. 2026, 15(10), 3707; https://doi.org/10.3390/jcm15103707 - 12 May 2026
Viewed by 378
Abstract
Background/Objectives: Post-COVID-19 condition involves heterogeneous, multisystem symptoms with uncertain recovery. We characterized symptom trajectories from hospitalization to approximately 4 weeks and to 6–8 months and compared the 6–8-month symptom burden with season-matched controls, accounting for serology-identified, previously unrecognized infections. Methods: An individually pair-matched [...] Read more.
Background/Objectives: Post-COVID-19 condition involves heterogeneous, multisystem symptoms with uncertain recovery. We characterized symptom trajectories from hospitalization to approximately 4 weeks and to 6–8 months and compared the 6–8-month symptom burden with season-matched controls, accounting for serology-identified, previously unrecognized infections. Methods: An individually pair-matched case–control study of adults with RT-PCR–confirmed SARS-CoV-2 and population controls from the Bialystok PLUS cohort, matched on age, sex and a two-month visit window, was performed. All participants underwent anti-nucleocapsid serology. Hospitalized cases were reassessed at approximately 4 weeks and 6–8 months. Cross-sectional outcomes used non-parametric tests and multivariable regression; longitudinal change used paired tests and generalized estimating equations. Results: We included 402 adults (201 post-COVID-19; 201 controls). In hospitalized cases, respiratory symptoms declined rapidly by approximately 4 weeks and remained low at 6–8 months; smell/taste recovered more slowly; fatigue improved modestly; anxiety changed minimally. At 6–8 months, total symptom counts were higher in post-COVID-19 than in controls (median 4 vs. 2), with serology-positive controls intermediate (median 3). Excess burden was concentrated in non-respiratory domains (fatigue, neurocognitive, cardiovascular, and dermatologic), whereas respiratory differences were not significant. In the multivariable model, female sex remained an independent predictor of higher multisystem burden, whereas age, body mass index, hospitalization, and acute biomarker severity were not associated. Conclusions: Six to eight months after symptomatic COVID-19, multisystem symptom burden remains substantial relative to season-matched controls, despite substantial resolution of respiratory complaints. Serology-based identification of previously unrecognized infections indicates an intermediate burden and can guide targeted follow-up. Full article
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15 pages, 2069 KB  
Article
Sentinel Surveillance of Influenza A in Libya: Subtyping and Genomic Analysis During Recent Seasons (2022–2024)
by Mahmud Azbida, Sana Ferjani, Omar Elahmer, Rmadhan Osman, Salem Shenaisheh, Amal Barakat, Salma Abid, Adem Eljerbi, Abdulwahab Kammon, Ameni Sallemi, Haider El-Saeh, Ilhem Boutiba-Ben Boubaker and Ibrahim Eldaghayes
Trop. Med. Infect. Dis. 2026, 11(5), 127; https://doi.org/10.3390/tropicalmed11050127 - 8 May 2026
Viewed by 1245
Abstract
Influenza sentinel surveillance in Libya was formally established in 2022 by the Libyan National Center for Disease Control (NCDC). Between 2022 and 2024, a total of 1864 nasopharyngeal specimens were collected from patients presenting with influenza-like illness and tested using the GeneXpert for [...] Read more.
Influenza sentinel surveillance in Libya was formally established in 2022 by the Libyan National Center for Disease Control (NCDC). Between 2022 and 2024, a total of 1864 nasopharyngeal specimens were collected from patients presenting with influenza-like illness and tested using the GeneXpert for influenza A virus, influenza B virus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and respiratory syncytial virus (RSV). Influenza A virus was detected in 21.1% (393/1864) of samples and influenza B virus was detected in 5.4% of samples (100/1864). SARS-CoV-2 and RSV were identified in 11.6% (216/1864) and 4.1% (77/1864) of specimens, respectively. A subset of 22 influenza A-positive samples was selected based on sample availability and sufficient remaining volume after the initial test for confirmatory testing and further molecular characterization. Real-time RT-PCR subtyping identified 11 A(H1N1)pdm09 and four A(H3N2) viruses. Whole-genome sequencing was successfully performed for 11 isolates, followed by phylogenetic analysis. Genetic characterization revealed that all A(H1N1)pdm09 viruses belonged to clade 6B.1A.5a.2a (5a.2a), while A(H3N2) viruses clustered within clade 3C.2a1b.2a.2a.3a.1 (2a.3a.1) were based on hemagglutinin gene mutations. No neuraminidase mutations associated with antiviral resistance were detected. This study represents the first molecular and phylogenetic characterization of circulating human influenza viruses in Libya, with sequence data submitted to the Global Initiative on Sharing All Influenza Data (GISAID) to establish baseline genetic data for influenza viruses in Libya. Full article
(This article belongs to the Section Infectious Diseases)
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17 pages, 546 KB  
Article
Respiratory Syncytial Virus-Associated Severe Acute Respiratory Infections in Hospitalized Patients at a University Hospital Center in Rabat, Morocco: An Epidemiological Overview
by Ghizlane El-Amin, Naima El Hafidi, Soumia Benchekroun, Mahraoui Chafiq, Amal Zouaki, Nora Touyar, Najat Bouihat, Salma Ech-Cherif El Kettani, Saad Harrak, Larbi Ed-Dafali, Aziza Bentalha, Mustapha Alilou, Hamza El Hamzaoui, Amina Barkat, Ilham Elouardighi, Tarek Dendane, Khalid Abidi, Jihane Bel Ayachi, Naoufal Madani, Redouane Abouqal, Hicham Harmouche, Mouna Maamar, Rachid El Jaoudi, Mourad Feindiri, Myriam Seffar, Mohamed Bouskraoui and Hakima Kabbajadd Show full author list remove Hide full author list
Viruses 2026, 18(5), 530; https://doi.org/10.3390/v18050530 - 30 Apr 2026
Viewed by 1797
Abstract
Respiratory syncytial virus (RSV) imposes a substantial burden of severe acute respiratory infection (SARI), especially in young children and the elderly. Methods: We describe RSV epidemiology among hospitalized SARI patients at the Ibn Sina University Hospital Center (Rabat, Morocco) from 1 January 2021, [...] Read more.
Respiratory syncytial virus (RSV) imposes a substantial burden of severe acute respiratory infection (SARI), especially in young children and the elderly. Methods: We describe RSV epidemiology among hospitalized SARI patients at the Ibn Sina University Hospital Center (Rabat, Morocco) from 1 January 2021, to 31 December 2025, using multiplex PCR (BioFire® RP2.1plus or Xpert® SARS-CoV-2/Flu/RSV). Results: Among 4604SARI samples, RSV prevalence was 16.1% (739/4604), predominantly pediatric (88.6%, p < 0.001), with peak burden in infants <6 months (70.4% of cases, p < 0.001). Pediatric prevalence was 28.3% (655/2316) vs. 3.8% (84/2204) in adults (p < 0.001), with predominance in the elderly ≥60 years (51/1041, 4.9%). Co-infections occurred in 46.7% (310/665) of FilmArray-tested positives (total = 665), led by rhinovirus/enterovirus (198/310, 63.9%), and were significantly higher in children (48.5%, p < 0.001). RSV peaked in winter (51.6%), except for summer dominance in 2021 (52.5%), reflecting COVID-19 non-pharmaceutical intervention effects. Conclusions: These data establish Morocco’s first comprehensive RSV surveillance baseline, highlighting post-pandemic epidemiological shifts. As maternal vaccines and monoclonal antibodies emerge, these data inform optimal implementation in low- and middle-income countries (LMICs). Full article
(This article belongs to the Special Issue RSV Epidemiological Surveillance: 3rd Edition)
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10 pages, 404 KB  
Article
Performance Evaluation of Instrument-Based SARS-CoV-2 Rapid Antigen Fluorescent Immunoassays for Point-of-Care Detection
by Vidya Keshav, Lesley Scott, Lucia Hans and Wendy Stevens
COVID 2026, 6(5), 78; https://doi.org/10.3390/covid6050078 - 30 Apr 2026
Viewed by 379
Abstract
Rapid antigen tests targeting SARS-CoV-2 nucleocapsid protein were essential for decentralised testing during the COVID-19 pandemic. Independent performance evaluations are essential to support regulatory approval and inform clinical implementation, particularly in resource-limited settings. This study presents a retrospective analytical and operational evaluation of [...] Read more.
Rapid antigen tests targeting SARS-CoV-2 nucleocapsid protein were essential for decentralised testing during the COVID-19 pandemic. Independent performance evaluations are essential to support regulatory approval and inform clinical implementation, particularly in resource-limited settings. This study presents a retrospective analytical and operational evaluation of two instrument-based fluorescent immunoassays (FIAs): the PCL COVID-19 Ag Rapid FIA and LumiraDx SARS-CoV-2 Ag Test. Analytical sensitivity was determined using recombinant nucleocapsid protein and viral cultures. Clinical performance was assessed using residual clinical specimens (n = 110) with RT-PCR as a reference, stratified by cycle threshold (Ct). Operational characteristics were assessed using a structured Likert framework. Overall sensitivity was 63% (51–73) for PCL and 95% (88–99) for LumiraDx. For Ct ≤ 25, sensitivity increased to 93% and 100%. Specificity was ≥97% for both. LumiraDx maintained sensitivity (83–94%) at Ct 25–30, whereas PCL did not detect any positives in this range. The limit of detection was 39 pM (PCL) and 0.6 pM (LumiraDx). Operational usability was high for both (90% PCL, 87% LumiraDx). LumiraDx showed higher analytical sensitivity across a broader viral load range, supporting primary diagnostic use, whereas PCL was limited to high viral loads. This evaluation provides a reproducible framework for rapid diagnostic assessment during emerging outbreaks. Full article
(This article belongs to the Special Issue Coronaviruses: Variants, Antivirals, and Vaccination)
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15 pages, 741 KB  
Article
Procalcitonin Levels in ICU Patients with SARS-CoV-2-Associated Viral Sepsis
by Barbara Adamik, Barbara Dragan, Tomasz Skalec, Piotr Badeński, Anna Kupiec, Małgorzata Grotowska, Lidia Łysenko, Adrianna Lebiedzińska, Agata Chalasiewicz, Agnieszka Matera-Witkiewicz, Adrian Doroszko, Katarzyna Kiliś-Pstrusińska, Michał Pomorski, Marcin Protasiewicz, Janusz Sokołowski, Krzysztof Kaliszewski, Ewa Anita Jankowska and Katarzyna Madziarska
J. Clin. Med. 2026, 15(9), 3339; https://doi.org/10.3390/jcm15093339 - 27 Apr 2026
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Abstract
Background: Sepsis has heterogeneous etiologies. Although bacteria are the most common causative agents, viral and yeast forms of sepsis also occur. Procalcitonin (PCT) is widely used to monitor severe bacterial infections and may support the differential diagnosis of infection etiology. Methods: [...] Read more.
Background: Sepsis has heterogeneous etiologies. Although bacteria are the most common causative agents, viral and yeast forms of sepsis also occur. Procalcitonin (PCT) is widely used to monitor severe bacterial infections and may support the differential diagnosis of infection etiology. Methods: We evaluated the diagnostic value of PCT in viral sepsis using PCT levels at ICU admission and PCT kinetics during ICU treatment. Results: During the COVID-19 pandemic, 191 adult ICU patients with sepsis and a positive SARS-CoV-2 PCR test at hospital admission were included and classified into two groups according to the presence or absence of bacterial or yeast co-infection. PCT showed a distinct diagnostic pattern influenced by the presence of co-infection. PCT remained low in isolated viral sepsis, whereas elevated concentrations were associated with superimposed bacterial or yeast co-infection and worse clinical outcomes. Overall mortality was significantly lower in patients with isolated viral sepsis compared to those with co-infection (50 vs. 69%, p = 0.009). Conclusions: In viral sepsis, persistently low PCT concentrations argue against bacterial co-infection, whereas elevated or rising values should prompt increased diagnostic evaluation. Although PCT provides clinically relevant diagnostic information, it must be interpreted cautiously and in conjunction with clinical assessment and microbiological data. PCT should serve as an adjunctive, not a standalone, marker of infection etiology in sepsis. Full article
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14 pages, 819 KB  
Article
Dynamics and Protective Effectiveness of Serological Testing Among Healthcare Workers Vaccinated Against COVID-19
by Vilija Gurkšnienė, Tadas Alčauskas, Dovilė Karosienė, Jurgita Urbonienė, Fausta Majauskaitė, Mindaugas Paulauskas, Birutė Zablockienė, Dalius Vitkus and Ligita Jančorienė
Medicina 2026, 62(5), 810; https://doi.org/10.3390/medicina62050810 - 24 Apr 2026
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Abstract
Background and Objectives: Healthcare workers are at heightened risk of SARS-CoV-2 infection. Understanding the duration and protective value of vaccine-induced immunity is critical to inform booster strategies. This study investigates longitudinal dynamics of anti-SARS-CoV-2 receptor-binding domain IgG (anti-RBD IgG) antibodies and their [...] Read more.
Background and Objectives: Healthcare workers are at heightened risk of SARS-CoV-2 infection. Understanding the duration and protective value of vaccine-induced immunity is critical to inform booster strategies. This study investigates longitudinal dynamics of anti-SARS-CoV-2 receptor-binding domain IgG (anti-RBD IgG) antibodies and their association with infection risk among vaccinated healthcare workers. Materials and Methods: A prospective cohort study was conducted at Vilnius University Hospital Santaros Klinikos, Lithuania. A total of 1778 healthcare workers who completed a primary COVID-19 vaccination series were followed. Blood samples were collected every three months to measure anti-RBD IgG levels. Participants also received up to three booster doses. COVID-19 was identified by PCR, antigen tests, or positive anti-nucleocapsid IgG. For serologically detected cases, infection timing was assigned to the interval between study visits. Antibody dynamics were analyzed across vaccination stages, time, age groups, and circulating SARS-CoV-2 variants. Results: Anti-RBD IgG titers peaked in the first quarter after primary vaccination (mean 7904 AU/mL), declined sharply by quarters 2–3, and rose substantially after booster doses. Following the first booster, titers increased to ~12,598 AU/mL in quarter 1 and continued rising through quarter 3. The highest levels were observed after the second booster (24,456 AU/mL in Q1), followed by gradual decline. A high-titer plateau persisted from quarters 6 to 9 (~21,000 AU/mL), followed by decline in quarters 10–11 and partial rebound in Q12. Approximately 49.6% of participants experienced COVID-19 during follow-up. Antibody response patterns were similar across age groups, with only minor transient differences. Conclusions: COVID-19 booster doses significantly enhance and prolong humoral immunity in healthcare workers compared with the primary vaccination series. However, antibody waning over time emphasizes the need for timely boosters, particularly during periods of variant circulation. These findings support continued booster vaccination and monitoring of long-term immune protection, although anti-RBD IgG should be interpreted as a surrogate marker of humoral rather than overall immunity. Full article
(This article belongs to the Section Epidemiology & Public Health)
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15 pages, 875 KB  
Article
Enhanced Detection of Multiple Viruses, Including Avian Influenza Virus, in Detroit Wastewater Using 24-Hour Swab Sampling and Magnetic Bead Purification
by Sneha Ghosh, Emily Sue Zak, Md Alamin, Carrie L. Turner, James Hartrick and Jeffrey L. Ram
Environments 2026, 13(5), 242; https://doi.org/10.3390/environments13050242 - 23 Apr 2026
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Abstract
Wastewater surveillance emerged as a critical public health tool during the COVID-19 pandemic, enabling early detection of community-level pathogen circulation independent of clinical testing. Its ability to capture signals from both symptomatic and asymptomatic individuals highlighted the importance of optimizing sampling methodologies to [...] Read more.
Wastewater surveillance emerged as a critical public health tool during the COVID-19 pandemic, enabling early detection of community-level pathogen circulation independent of clinical testing. Its ability to capture signals from both symptomatic and asymptomatic individuals highlighted the importance of optimizing sampling methodologies to improve sensitivity and reliability. A key question is whether the several-fold increase in SARS-CoV-2 detectability observed when using passive tampon swab sampling compared with paired grab samples also applies to other respiratory viruses, including influenza A (including its avian influenza H5N1 subtype), influenza B, and respiratory syncytial virus (RSV). We collected 24 h passive swab samples with same-day grab samples from Detroit sewersheds, concentrated and purified nucleic acids, and using RT-ddPCR, quantified respiratory syncytial virus, SARS-CoV-2, influenza A, influenza B, and H5N1 influenza A viruses using markers RSV, SC2, InfA, InfB, and H5, respectively. Samples testing positive for H5 (marker for H5N1 influenza A) were further analyzed by targeted PCR and amplicon sequencing. Across three sites, median 24 h swab:grab ratios of virus copies were 7.0 for RSV, 9.2 for SC2, 9.9 for InfA, and 3.6 for InfB. A 239 bp hemagglutinin sequence from a sample with a strong H5 signal (795 copies/10 mL) had 100% identity to avian influenza viruses from Canada geese. Twenty-four-hour swab sampling greatly improves viral detectability across diverse targets and enabled the first confirmed detection of H5 in Detroit wastewater. Combined with magnetic bead purification, the overall sensitivity gain over conventional PEG-NaCl-Qiagen methods is approximately 36-fold, enabling earlier warning of community pathogens than grab samples. By integrating 24 hour passive swab sampling with high-efficiency nucleic acid purification, we expand the sensitivity of wastewater surveillance to enable detection and confirmation of low-abundance pathogens like avian influenza (H5). Full article
(This article belongs to the Special Issue Wastewater-Based Epidemiology Assessment and Surveillance)
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