Search Results (39)

Background: During the 2023–2024 season, the influenza epidemic in South Korea peaked earlier, and the influenza vaccination rate among individuals aged ≥ 65 was high (82.2%). However, data on real-world vaccine effectiveness against influenza are lacking. Methods: From November 2023 to April 2024, we conducted a multicenter retrospective case–control study on adult patients aged ≥ 18 years who presented with influenza-like illness at seven medical centers as a part of a hospital-based influenza morbidity and mortality surveillance (HIMM) program in South Korea. Demographic and clinical data were collected from questionnaire surveys and electronic medical records. Using a test-negative design, we assessed the effectiveness of the 2023–2024 seasonal influenza vaccine, with age, sex, and comorbidities included as covariates. Results: A total of 3390 participants were enrolled through the HIMM system, including 1695 patients with either rapid antigen test (RAT) or real-time reverse-transcription polymerase chain reaction (RT-PCR) positive results and controls matched for age, sex, and months of registration. Among the 1696 influenza-positive patients, 1584 (93.5%) underwent RAT, with 88.9% testing positive for influenza A and 11.1% for influenza B. During the study periods, the overall vaccine effectiveness (VE) was 24.3% (95% confidence interval (CI), 11.5 to 35.2). The VE was insignificant when limited to older adults aged ≥ 65 years (13.5%; 95% CI, −17.9 to 36.6). In the subgroup analysis by subtype, the VE was 19.0% (95% CI, 5.0 to 31.0) for influenza A and 56.3% (95% CI, 35.3 to 70.6) for influenza B. Notably, influenza VE was 20.4% (95% CI, 2.9 to 34.8) in the early period (November to December) but decreased to 12.4% (95% CI, −14.9 to 33.2) in the late period (January to April). Conclusion: During the 2023–2024 season, the influenza vaccine showed a modest effectiveness (24.3%) against laboratory-confirmed influenza, which was particularly higher for influenza B. Because the VE was insignificant in older adults, particularly during the late period, better immunogenic influenza vaccines with longer-lasting protection should be considered. Full article

Background: SARS-CoV-2 is classified as a class 3 biological agent; therefore, autopsies on positive subjects must be performed in BSL 3 sectorial rooms. However, many centers lacking such facilities perform molecular nasopharyngeal swabs for SARS-CoV-2 on corpses before autopsy. This approach, though, is marked by prolonged reporting times and extremely high costs. This study aims to compare the results of molecular swabs (RT-PCR) with rapid antigen swabs (RAT) in order to assess if RAT can serve as the sole test for determining corpse positivity or negativity. Methods: Sixty corpses with positive molecular nasopharyngeal swabs for SARS-CoV-2, performed either ante-mortem or post-mortem, were selected. Afterward, they underwent rapid antigen swabs within 0 to 11 days after the last molecular exam. Results: Out of 60 corpses with positive molecular swabs, 52 antigen swabs were positive (86.67%), and 8 were negative (13.33%), indicating a sensitivity of 86.66% and specificity of 100%. Conclusions: Considering the sensitivity and specificity values observed in this study, RAT could be used as the primary investigation on corpses, especially in centers that lack BSL 3 sectorial rooms. Molecular swabs could then serve as a secondary test for subjects negative on RAT. Full article

Acute respiratory infections are a significant challenge in primary care and hospital settings. Viruses are the most common etiology and the overlapping symptomatology among major respiratory viruses, such as influenza, severe acute respiratory syndrome coronavirus 2, and respiratory syncytial virus, requires the use of diagnostic tests that deliver early and accurate results. With the increasing availability of rapid antigen tests (RATS), it is tempting to prefer them over polymerase chain reaction (PCR) tests. However, compelling arguments support the existing recommendations in some European countries to maintain PCR testing for patient management throughout the year. RATs show sensitivities below 30% with lower viral loads, which are common and can have significant clinical implications. RATs perform well at lower cycle threshold (Ct) values, with sensitivity reaching 97.9% for Ct values below 20, which drops significantly for values above 25. Factors affecting viral load include disease stage, vaccination status, and viral variants, all of which can compromise the accuracy of antigen tests. Multi-target PCR tests effectively overcome these issues, ensuring reliable diagnosis. Additionally, the early detection of paucisymptomatic cases is essential in primary care and hospital settings to facilitate isolation and prevent secondary infections. Economic analyses support the use of comprehensive PCR tests, such as triplex-type tests, detecting SARS-CoV-2, influenza viruses, and RSV, as a first-line approach, as they can reduce case numbers and healthcare resource utilization. Maintaining PCR testing year-round is therefore crucial for the effective management of respiratory infections. Full article

Background: The impact of COVID-19 on pregnancy remains a critical area of research, with growing evidence suggesting that maternal infection, particularly in the third trimester, may lead to significant complications Aims: The primary aim was to investigate the maternal and neonatal outcome of pregnant Jordanian women with COVID-19. The secondary aim included exploring demographics, obstetrics characteristics, and comorbidities among these women. Methods: A retrospective comprehensive review of the records of 300 cases of pregnant women with COVID-19, who were treated between November 2020 and April 2021 at Queen Alia Military Hospital (a main referral center for patients with COVID-19) in Jordan. All cases were confirmed by the rapid antigen test (RAT) + long polymerase chain reaction (PCR) test used to detect SARS-CoV-2 by amplifying viral RNA from patient samples. Women infected with COVID-19 were categorized into four groups according to the RCOG guidelines for COVID-19 infection in pregnancy: asymptomatic, mild, moderate, and severe cases. All cases were managed following the Royal College of Obstetricians and Gynecologists protocol for COVID-19 in pregnancy. Data extracted from patient’s records included demographic information, COVID-19 clinical manifestations, obstetric history, diagnostic findings, treatment plans, comorbidities, gestational age at diagnosis, treatment protocols, and maternal and neonatal outcomes. Results: The mean age was 29.7 years; 98.3% were nonsmokers; 8% had previous miscarriages, and 67.3% had the infection in the third trimester. Iron deficiency anemia affected 30.3%, while 18.3% had comorbidities, mainly hypothyroidism. Most women were asymptomatic 61.7%, but 33% had respiratory symptoms, 4.7% needed intensive care unit (ICU) admission, and 2.7% resulted in maternal deaths. First-trimester and second-trimester miscarriages were recorded in 2.67% and 3.67% of cases, respectively, while preterm labor occurred in 3.0% of pregnancies. Additionally, age and hospitalization duration had a positive correlation with the neonatal outcomes (r = 0.349, p < 0.01), (r = 0.376, p < 0.01), respectively. Furthermore, COVID-19 presentation and treatment options demonstrated a strong positive correlation (p-value <0.01). On the other hand, maternal death had a strong negative correlation with poor neonatal outcomes (r = −0.776, p < 0.01). Conclusion: The study showed that COVID-19 in pregnant women, particularly in the third trimester, is associated with significant neonatal complications, with age, hospitalization duration, and COVID-19 severity strongly impacting outcomes. Full article

This study comprehensively evaluated the DNA/RNA Defend Pro (DRDP) sample collection buffer, designed to inactivate and stabilize patient samples. The primary objectives were to assess DRDP’s efficacy in ensuring sample stability, facilitating extraction-free polymerase chain reaction (PCR), and ensuring compatibility with rapid antigen testing (RAT). Ninety-five diagnostic nasopharyngeal swab samples tested for influenza virus (influenza A), respiratory syncytial virus (RSV A), and/or severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were 10-fold diluted with DRDP and anonymized. Initial characterization and retesting of these samples using cobas Liat confirmed 88 samples as positive, validating the presence of viral targets. Results from rapid antigen testing showed lower sensitivity compared to nucleic acid amplification testing (NAAT) but maintained perfect specificity, with 40 out of 88 positive samples by cobas Liat also testing positive for RAT. Direct RT-qPCR of DRDP-diluted samples demonstrated robust compatibility, with 72 out of 88 samples positive for cobas Liat also testing positive by direct RT-qPCR. Non-concordant results could be explained by the 200-fold lower input of extraction-free NAAT. Stability testing involved incubating 31 positive samples at 4 °C, 20 °C, and 37 °C for 7 days, with extraction-free NAAT. DRDP guaranteed viral RNA stability at all temperatures for influenza A, SARS-CoV-2, and RSV A, showing stability up to 7 days at 4 °C. In conclusion, DRDP is an effective stabilizing medium compatible with direct RT-qPCR and rapid antigen testing and shows great potential for optimizing diagnostic processes, particularly in resource-limited or time-sensitive scenarios. Full article

Background: Community infections of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have increased rapidly since the emergence of the Omicron strain. During the eighth and ninth pandemic waves—when movement restrictions in the community were eased—the all-case registration system was changed, and the actual status of infection became uncertain. Methods: We conducted regular rapid antigen tests (R-RATs) once or twice a week as self-testing to examine the actual state of coronavirus disease (COVID-19) diagnosis among healthcare employees. Results: Overall, 320 (1.42/day) and 299 (1.76/day) employees were infected in the eighth and ninth pandemic waves. During both periods, 59/263 doctors (22.4%), 335/806 nurses (41.6%), 92/194 administrative employees (47.4%), and 129/218 clinical laboratory technicians (59.2%) were infected. In the eighth wave, 56 of 195 employees were infected through close contact; in the ninth wave, 26 of 62 employees were infected. No significant difference was observed in the number of vaccinations between infected and non-infected employees. The positivity rate of R-RATs was 0.41% and 0.45% in the eighth and ninth waves. R-RATs detected infection in 212 and 229 employees during the eighth and ninth waves, respectively; the ratio of R-RAT-detected positive employees to those who reported infection was significantly higher during the ninth wave (odds ratio: 1.67, 95% confidence interval: 1.17–2.37, p < 0.001). Conclusions: The number of infected healthcare employees remained high during the eighth and ninth pandemic waves in Japan. The R-RAT is considered effective for detecting mild or asymptomatic COVID-19 at an early stage and at a high rate in healthcare employees. Full article

The COVID-19 pandemic caused by the virus SARS-CoV-2 was the greatest global threat to human health in the last three years. The most widely used methodologies for the diagnosis of COVID-19 are quantitative reverse transcription polymerase chain reaction (RT-qPCR) and rapid antigen tests (RATs). PCR is time-consuming and requires specialized instrumentation operated by skilled personnel. In contrast, RATs can be used in-home or at point-of-care but are less sensitive, leading to a higher rate of false negative results. In this work, we describe the development of a disposable, electrochemical, and laser-scribed graphene-based biosensor strips for COVID-19 detection that exploits a split-ester bond ligase system (termed ‘EsterLigase’) for immobilization of a virus-specific nanobody to maintain the out-of-plane orientation of the probe to ensure the efficacy of the probe-target recognition process. An anti-spike VHH E nanobody, genetically fused with the EsterLigase domain, was used as the specific probe for the spike receptor-binding domain (SP-RBD) protein as the target. The recognition between the two was measured by the change in the charge transfer resistance determined by fitting the electrochemical impedance spectroscopy (EIS) spectra. The developed LSG-based biosensor achieved a linear detection range for the SP-RBD from 150 pM to 15 nM with a sensitivity of 0.0866 [log(M)]⁻¹ and a limit of detection (LOD) of 7.68 pM. Full article

Single-target rapid antigen tests (RATs) are commonly used to detect highly transmissible respiratory viruses (RVs), such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and influenza viruses. The simultaneous detection of RVs presenting overlapping symptoms is vital in making appropriate decisions about treatment, isolation, and resource utilization; however, few studies have evaluated multiplex RATs for SARS-CoV-2 and other RVs. We assessed the diagnostic performance of multiplex RATs targeting both the SARS-CoV-2 and influenza A/B viruses with the GenBody Influenza/COVID-19 Ag Triple, InstaView COVID-19/Flu Ag Combo (InstaView), STANDARD^TM Q COVID-19 Ag Test, and STANDARD^TM Q Influenza A/B Test kits using 974 nasopharyngeal swab samples. The cycle threshold values obtained from the real-time reverse transcription polymerase chain reaction results showed higher sensitivity (72.7–100%) when the values were below, rather than above, the cut-off values. The InstaView kit exhibited significantly higher positivity rates (80.21% for SARS-CoV-2, 61.75% for influenza A, and 46.15% for influenza B) and cut-off values (25.57 for SARS-CoV-2, 21.19 for influenza A, and 22.35 for influenza B) than the other two kits, and was able to detect SARS-CoV-2 Omicron subvariants. Therefore, the InstaView kit is the best choice for routine screening for both SARS-CoV-2 and influenza A/B in local communities. Full article

The COVID-19 pandemic has transformed laboratory management, with a surge in demand for diagnostic tests prompting the adoption of new diagnostic assays and the spread of variant surveillance tools. Rapid antigen tests (RATs) were initially used only for screening and later as suitable infection assessment tools. This study explores the feasibility of sequencing the SARS-CoV-2 genome from the residue of the nasopharyngeal swab extraction buffers of rapid antigen tests (RATs) to identify different COVID-19 lineages and sub-lineages. Methods: Viral RNA was extracted from the residue of the nasopharyngeal swab extraction buffers of RATs and, after a confirmation of positivity through a reaction of RT-PCR, viral genome sequencing was performed. Results: Overall, the quality of the sequences obtained from the RNA extracted from the residue of the nasopharyngeal swab extraction buffers of RATs was adequate and allowed us to identify the SARS-CoV-2 variants’ circulation and distribution in a period when the use of molecular swabs had been drastically reduced. Conclusions: This study demonstrates the potential for genomic surveillance by sequencing SARS-CoV-2 from the residue of the nasopharyngeal swab extraction buffers of RATs, highlighting alternative possibilities for tracking variants. Full article

Since its discovery in late 2019, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been estimated to be responsible for at least 769.3 million infections and over 6.95 million deaths. Despite significant global vaccination efforts, there are limited therapies that are considered safe and effective for use in the management of COVID-19 during pregnancy despite the common knowledge that pregnant patients have a much higher risk of adverse outcomes. A bioactive compound found in broccoli sprout—sulforaphane—is a potent inducer of phase-II detoxification enzymes promoting a series of potentially beneficial effects notably as an antioxidant, anti-inflammatory, and anti-viral. A pilot, double-blinded, placebo-controlled randomised trial is to be conducted in Melbourne, Australia, across both public and private hospital sectors. We will assess a commercially available broccoli sprout extract in pregnant women between 20⁺⁰ and 36⁺⁰ weeks gestation with SARS-CoV-2 infection to investigate (i) the duration of COVID-19 associated symptoms, (ii) maternal and neonatal outcomes, and (iii) biomarkers of infection and inflammation. We plan to enrol 60 outpatient women with COVID-19 irrespective of vaccination status diagnosed by PCR swab or RAT (rapid antigen test) within five days and randomised to 14 days of oral broccoli sprout extract (42 mg of sulforaphane daily) or identical microcrystalline cellulose placebo. The primary outcome of this pilot trial will be to assess the feasibility of conducting a larger trial investigating the duration (days) of COVID-19-associated symptoms using a broccoli sprout supplement for COVID-19-affected pregnancies. Pregnant patients remain an at-risk group for severe disease following infection with SARS-CoV-2 and currently unclear consequences for the offspring. Therefore, this study will assess feasibility of using a broccoli sprout supplement, whilst providing important safety data for the use of sulforaphane in pregnancy. Full article

Rapid antigen testing (RAT) is a cost-effective and time-efficient method of identifying severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and therefore a critical part of infection control strategies. There is no published evidence evaluating the use of RAT during the Omicron wave of the COVID-19 pandemic for asymptomatic patients or its performance between waves. All patients presenting to an Emergency Department over a two-week period without COVID-19 symptoms were screened for SARS-CoV-2 using both the Abbott Panbio RAT as well as the gold standard reverse transcriptase real-time polymerase chain reaction (PCR). The Abbott Panbio RAT sensitivity was 13% (95% CI 0.028, 0.336) for asymptomatic patients. The use of this test in asymptomatic patients during the Omicron wave had a statistically significant reduction in sensitivity compared with two reports of the same test in previous waves (13% vs. 86%, p < 0.0001; 13% vs. 83%, p < 0.0001). As SARS-CoV-2 continues to mutate, the sensitivity of RATs are altered and needs to be continually re-evaluated for each variant of concern if they are to be used as part of an infection control strategy. Full article

Rapid antigen tests (RATs) are diagnostic tools developed to specifically detect a certain protein of infectious agents (viruses, bacteria, or parasites). RATs are easily accessible due to their rapidity and simplicity. During the COVID-19 pandemic, RATs have been widely used in detecting the presence of the specific SARS-CoV-2 antigen in respiratory samples from suspected individuals. Here, the authors review the application of RATs as detection tools for COVID-19, particularly in Korea, as well as for several other infectious diseases. To address these issues, we present general knowledge on the design of RATs that adopt the lateral flow immunoassay for the detection of the analyte (antigen). The authors then discuss the clinical utilization of the authorized RATs amidst the battle against the COVID-19 pandemic in Korea and their role in comparison with other detection methods. We also discuss the implementation of RATs for other, non-COVID-19 infectious diseases, the challenges that may arise during the application, the limitations of RATs as clinical detection tools, as well as the possible problem solving for those challenges to maximize the performance of RATs and avoiding any misinterpretation of the test result. Full article

Owing to the high transmissibility of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants, the capacity of testing systems based on the gold standard real-time reverse transcription–polymerase chain reaction (rRT-PCR) is limited. Rapid antigen tests (RATs) can substantially contribute to the prevention of community transmission, but their further assessment is required. Here, using 1503 nasopharyngeal swabs, we compared the diagnostic performance of four RAT kits (Abbott Panbio™ COVID-19 Ag Rapid Test, SD Biosensor Standard™ Q COVID-19 Ag Test, Humasis COVID-19 Ag Test, and SG Medical Acrosis COVID-19 Ag Test) to the cycle threshold (Ct) values obtained from rRT-PCR. The precision values, area under the curve values, SARS-CoV-2 variant detection ability, and non-SARS-CoV-2 specificity of all four kits were similar. An assay using the Acrosis kit had a significantly better positive detection rate with a higher recall value and cut-off value than that using the other three RAT kits. During the current COVID-19 pandemic, the Acrosis kit is an effective tool to prevent the spread of SARS-CoV-2 in communities. Full article

Accurate and rapid identification of COVID-19 is critical for effective patient treatment and disease outcomes, as well as the prevention of SARS-CoV-2 transmission. Rapid antigen tests (RATs) for identifying SARS-CoV-2 are simpler, faster and less expensive than molecular assays. Any new product to be considered a medical device is subject to evaluation and data analysis to verify the in vitro diagnostic ability to achieve its intended purpose. Clinical validation of such a test is a prerequisite before clinical application. This study was a clinical validation on adult Europeans of GenBody COVID-19 Ag, nasal and nasopharyngeal RATs. A set of 103 positive and 301 negative from nose and nasopharynx samples confirmed by RT-qPCR were examined. The tests were safe to use and showed 100% specificity in both specimens, and high sensitivity of 94.17% (95%CI 87.75% to 97.83%) and 97.09% (95%CI 91.72% to 99.4%), respectively. The parameters were significantly better for samples with higher virus loads (the highest for CT ≤ 25). The GenBody COVID-19 Ag RATs are inexpensive (compared to RT-qPCR), reliable and rapid with high sensitivity and specificity, making them suitable for diagnosis and timely isolation and treatment of COVID-19 patients, contributing to the better control of virus spread. Full article

The COVID-19 pandemic revealed a pressing need for the development of sensitive and low-cost point-of-care sensors for disease diagnosis. The current standard of care for COVID-19 is quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). This method is sensitive, but takes time, effort, and requires specialized equipment and reagents to be performed correctly. This make it unsuitable for widespread, rapid testing and causes poor individual and policy decision-making. Rapid antigen tests (RATs) are a widely used alternative that provide results quickly but have low sensitivity and are prone to false negatives, particularly in cases with lower viral burden. Electrochemical sensors have shown much promise in filling this technology gap, and impedance spectroscopy specifically has exciting potential in rapid screening of COVID-19. Due to the data-rich nature of impedance measurements performed at different frequencies, this method lends itself to machine-leaning (ML) algorithms for further data processing. This review summarizes the current state of impedance spectroscopy-based point-of-care sensors for the detection of the SARS-CoV-2 virus. This article also suggests future directions to address the technology’s current limitations to move forward in this current pandemic and prepare for future outbreaks. Full article