Coronavirus Disease 19 (COVID-19) Vaccine Effectiveness Against Symptomatic Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infection During Delta-Dominant and Omicron-Dominant Periods in Japan: A Multicenter Prospective Case-control Study (Factors Associated with SARS-CoV-2 Infection and the Effectiveness of COVID-19 Vaccines Study).

BACKGROUND: Although several coronavirus disease 2019 (COVID-19) vaccines initially showed high efficacy, there have been concerns because of waning immunity and the emergence of variants with immune escape capacity. METHODS: A test-negative design case-control study was conducted in 16 healthcare facilities in Japan during the Delta-dominant period (August-September 2021) and the Omicron-dominant period (January-March 2022). Vaccine effectiveness (VE) against symptomatic severe acute respiratory syndrome coronavirus 2 infection was calculated for 2 doses for the Delta-dominant period and 2 or 3 doses for the Omicron-dominant period compared with unvaccinated individuals. RESULTS: The analysis included 5795 individuals with 2595 (44.8%) cases. Among vaccinees, 2242 (55.8%) received BNT162b2 and 1624 (40.4%) received messenger RNA (mRNA)-1273 at manufacturer-recommended intervals. During the Delta-dominant period, VE was 88% (95% confidence interval [CI], 82-93) 14 days to 3 months after dose 2 and 87% (95% CI, 38-97) 3 to 6 months after dose 2. During the Omicron-dominant period, VE was 56% (95% CI, 37-70) 14 days to 3 months since dose 2, 52% (95% CI, 40-62) 3 to 6 months after dose 2, 49% (95% CI, 34-61) 6+ months after dose 2, and 74% (95% CI, 62-83) 14+ days after dose 3. Restricting to individuals at high risk of severe COVID-19 and additional adjustment for preventive measures (ie, mask wearing/high-risk behaviors) yielded similar estimates, respectively. CONCLUSIONS: In Japan, where most are infection-naïve, and strict prevention measures are maintained regardless of vaccination status, 2-dose mRNA vaccines provided high protection against symptomatic infection during the Delta-dominant period and moderate protection during the Omicron-dominant period. Among individuals who received an mRNA booster dose, VE recovered to a high level.

Cerebral blood flow abnormalities with central sparing on arterial spin labeling in mild encephalopathy associated with excitotoxicity: a case report.

BACKGROUND: Acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) and mild encephalopathy associated with excitotoxicity (MEEX) are the most frequent acute encephalopathies in pediatric patients in Japan. AESD typically presents with biphasic seizures and delayed reduced diffusion in the subcortical area, called bright tree appearance (BTA), on radiological examination. In patients with AESD, arterial spin labeling (ASL) shows decreased cerebral blood flow (CBF) in the hyperacute stage and increased CBF in the acute stage, suggesting the usefulness of ASL for the early diagnosis of AESD. Additionally, proton magnetic resonance spectroscopy (MRS) shows elevated glutamate (Glu) and glutamine (Gln) in AESD. MEEX is a group of mild encephalopathies with transient elevation of Gln on MRS similar to that in AESD; however, MEEX does not include any clinical biphasic course or abnormalities, including BTA on diffusion-weighted imaging. Although the usefulness of ASL for AESD has been reported, there are no reports for patients with MEEX. In this study, we report our experience with a 4-year-old girl diagnosed with MEEX who showed unique findings on ASL. CASE PRESENTATION: The patient was a 4-year-old girl admitted to the emergency room with febrile status epilepticus. Considering the possibility of AESD, vitamin therapy was initiated. ASL-MR imaging (MRI) of the brain performed on the second day showed increased blood flow in the frontal, temporal, and occipital regions with spared central sulcus, which indicated AESD with central sparing. The patient was diagnosed with AESD, and the treatment included pulse steroid therapy and immunoglobulin therapy from day 3. The patient remained mildly unconscious but gradually became conscious by day 7 with no seizures. Brain MRI performed on day 8 did not show any characteristic AESD findings, such as BTA. Furthermore, MRS showed elevated Gln, which, along with the clinical course, led to the diagnosis of MEEX. The patient was discharged on day 16 without obvious sequelae. CONCLUSIONS: ASL may be useful in the early diagnosis of MEEX as well as AESD, facilitating early intervention.

Neurogenic pulmonary edema following febrile status epilepticus in a 22-month-old infant with multiple respiratory virus co-detection: a case report.

BACKGROUND: Neurogenic pulmonary edema is a rare but serious complication of febrile status epilepticus in children. Comprehensive screening for viral pathogens is seldomly performed in the work-up of febrile children. CASE PRESENTATION: A 22-month-old girl presented with her first episode of febrile status epilepticus, after which she developed acute pulmonary edema and respiratory failure. After the termination of seizure activity, the patient was intubated and managed on mechanical ventilation in the emergency room. The resolution of respiratory failure, as well as the neurological recovery, was achieved 9 h after admission, and the patient was discharged 6 days after admission without any complications. Molecular biological diagnostic methods identified the presence of human coronavirus HKU1, influenza C virus, and human parainfluenza virus 2 from the patient's nasopharyngeal specimens. CONCLUSIONS: Neurogenic pulmonary edema following febrile status epilepticus was suspected to be the etiology of our patient's acute pulmonary edema and respiratory failure. Timely seizure termination and rapid airway and respiratory intervention resulted in favorable outcomes of the patient. Molecular biological diagnostic methods identified three respiratory viruses; however, their relevance and association with clinical symptoms remain speculative.

Development of real-time fluorescent reverse transcription loop-mediated isothermal amplification assays for rhinovirus detection.

Human rhinoviruses (RVs) belong to the genus Enterovirus of the family Picornaviridae, and are classified into RV-A, -B, and -C species. Two assays were developed to detect RVs by a real-time fluorescent reverse transcription loop-mediated isothermal amplification method: one was designed based on the 5'-untranslated regions (UTRs) of RV-A and -B, and the other was designed based on the 5'-UTR of RV-C. The competence of both assays for the diagnosis of RV infection was tested using isolated viruses and compared with real-time reverse transcription polymerase chain reaction assays on clinical specimens. Neither assay demonstrated cross-reactivity with other tested enteroviruses, and they detected 19 out of 21 tested RV-As and seven out of eight tested RV-Cs. The specificity of the assays was 100% for the detection of RVs and their sensitivity for RV-A and RV-C was 86.3% and 77.3%, respectively, on clinical specimens by the combined use of both assays. Considering that both developed assays were highly specific and detected the majority of recently circulating RVs, they are helpful for the diagnosis of RV infection. Consequently, the results generated by these assays will enhance the surveillance of respiratory illness and the study of the roles of RVs associated with clinical features and disease severity.

Development and evaluation of a new real-time RT-PCR assay for detecting the latest H9N2 influenza viruses capable of causing human infection.

The H9N2 subtype of avian influenza A viruses (AIV) has spread among domestic poultry and wild birds worldwide. H9N2 AIV is sporadically transmitted to humans from avian species. A total of 42 laboratory-confirmed cases of non-fatal human infection with the Eurasian Y280 and G1 lineages have been reported in China, Hong Kong, Bangladesh and Egypt since 1997. H9N2 AIV infections in poultry have become endemic in Asia and the Middle East and are a major source of viral internal genes for other AIV subtypes, such that continuous monitoring of H9N2 AIV is recommended. In this study, a new, one-step, real-time RT-PCR assay was developed to detect two major Eurasian H9 lineages of AIV capable of causing human infection. The sensitivity of this assay was determined using in vitro-transcribed RNA, and the detection limit was approximately 3 copies/reaction. In this assay, no cross-reactivity was observed against RNA from H1-15 subtypes of influenza A viruses, influenza B viruses and other viral respiratory pathogens. In addition, this assay could detect the H9 hemagglutinin (HA) gene from artificially reconstituted clinical samples spiked with H9N2 virus without any non-specific reactions. Therefore, this assay is highly sensitive and specific for H9 HA detection. The assay is useful both for diagnostic purposes in cases of suspected human infection with influenza H9N2 viruses and for the surveillance of both avian and human influenza viruses.

Streptococcal toxic shock syndrome caused by the dissemination of an invasive emm3/ST15 strain of Streptococcus pyogenes.

BACKGROUND: Streptococcus pyogenes (group A Streptococcus [GAS]) is a major human pathogen that causes a wide spectrum of clinical manifestations. Although invasive GAS (iGAS) infections are relatively uncommon, emm3/ST15 GAS is a highly virulent, invasive, and pathogenic strain. Global molecular epidemiology analysis has suggested that the frequency of emm3 GAS has been recently increasing. CASE PRESENTATION: A 14-year-old patient was diagnosed with streptococcal toxic shock syndrome and severe pneumonia, impaired renal function, and rhabdomyolysis. GAS was isolated from a culture of endotracheal aspirates and designated as KS030. Comparative genome analysis suggested that KS030 is classified as emm3 (emm-type) and ST15 (multilocus sequencing typing [MLST]), which is similar to iGAS isolates identified in the UK (2013) and Switzerland (2015). CONCLUSIONS: We conclude that the global dissemination of emm3/ST15 GAS strain has the potential to cause invasive disease.

Development of a real-time fluorescent reverse transcription loop-mediated isothermal amplification assay with quenching primers for rapid detection of rubella virus.

Rubella virus infection during early pregnancy sometimes causes severe birth defects termed congenital rubella syndrome. Although there are safe and effective live-attenuated vaccines, rubella has only been certified as eliminated in the Americas within the six World Health Organization regions. Rubella remains an endemic disease in many regions, and outbreaks occur wherever population immunity is insufficient. There are two main methods for diagnosis of rubella: detection of anti-rubella IgM antibodies by enzyme immunoassay and detection of the viral genome by real-time RT-PCR. Both of these methods require substantial time and effort. In the present study, a rapid rubella detection assay using real-time fluorescent reverse transcription loop-mediated isothermal amplification with quenching primers was developed. The time required for the new assay was one-half that required for a real-time RT-PCR assay. The assay had 93.6% positive percent agreement and 100% negative percent agreement for clinical specimens compared with the real-time RT-PCR assay. The new assay is considered useful for diagnosis of rubella in areas where rubella is endemic.

COVID-19 vaccine effectiveness against severe COVID-19 requiring oxygen therapy, invasive mechanical ventilation, and death in Japan: A multicenter case-control study (MOTIVATE study).

INTRODUCTION: Since the SARS-CoV-2 Omicron variant became dominant, assessing COVID-19 vaccine effectiveness (VE) against severe disease using hospitalization as an outcome became more challenging due to incidental infections via admission screening and variable admission criteria, resulting in a wide range of estimates. To address this, the World Health Organization (WHO) guidance recommends the use of outcomes that are more specific to severe pneumonia such as oxygen use and mechanical ventilation. METHODS: A case-control study was conducted in 24 hospitals in Japan for the Delta-dominant period (August-November 2021; "Delta") and early Omicron (BA.1/BA.2)-dominant period (January-June 2022; "Omicron"). Detailed chart review/interviews were conducted in January-May 2023. VE was measured using various outcomes including disease requiring oxygen therapy, disease requiring invasive mechanical ventilation (IMV), death, outcome restricting to "true" severe COVID-19 (where oxygen requirement is due to COVID-19 rather than another condition(s)), and progression from oxygen use to IMV or death among COVID-19 patients. RESULTS: The analysis included 2125 individuals with respiratory failure (1608 cases [75.7%]; 99.2% of vaccinees received mRNA vaccines). During Delta, 2 doses provided high protection for up to 6 months (oxygen requirement: 95.2% [95% CI:88.7-98.0%] [restricted to "true" severe COVID-19: 95.5% {89.3-98.1%}]; IMV: 99.6% [97.3-99.9%]; fatal: 98.6% [92.3-99.7%]). During Omicron, 3 doses provided high protection for up to 6 months (oxygen requirement: 85.5% [68.8-93.3%] ["true" severe COVID-19: 88.1% {73.6-94.7%}]; IMV: 97.9% [85.9-99.7%]; fatal: 99.6% [95.2-99.97]). There was a trend towards higher VE for more severe and specific outcomes. CONCLUSION: Multiple outcomes pointed towards high protection of 2 doses during Delta and 3 doses during Omicron. These results demonstrate the importance of using severe and specific outcomes to accurately measure VE against severe COVID-19, as recommended in WHO guidance in settings of intense transmission as seen during Omicron.

Effectiveness of BA.1- and BA.4/BA. 5-Containing Bivalent COVID-19 mRNA Vaccines Against Symptomatic SARS-CoV-2 Infection During the BA.5-Dominant Period in Japan.

In this multicenter, prospective, test-negative, case-control study in Japan, the effectiveness of both BA.1-containing and BA.4/BA.5-containing bivalent coronavirus disease 2019 mRNA vaccines against symptomatic infection during the BA.5-dominant period was high compared with no vaccination (65% and 76%) and moderate compared with monovalent vaccines administered over half a year earlier (46% combined).

Immune escape and waning immunity of COVID-19 monovalent mRNA vaccines against symptomatic infection with BA.1/BA.2 and BA.5 in Japan.

BACKGROUND: Repeated emergence of variants with immune escape capacity and waning immunity from vaccination are major concerns for COVID-19. We examined whether the surge in Omicron subvariant BA.5 cases was due to immune escape or waning immunity through vaccine effectiveness (VE) evaluation. METHODS: A test-negative case-control study was conducted in 16 clinics/hospitals during the BA.1/BA.2-dominant and BA.5-dominant periods. VE against symptomatic infection was estimated after adjusting for age, sex, comorbidity, occupation, testing frequency, prior infection, close contact history, clinic/hospital, week, and preventive measures. Absolute VE (aVE) was calculated for 2/3/4 doses, compared to the unvaccinated. Relative VE (rVE) was calculated, comparing 3 vs 2 and 4 vs 3 doses. RESULTS: 13,025 individuals were tested during the BA.1/BA.2-dominant and BA.5-dominant periods with similar baseline characteristics. For BA.1/BA.2, aVE was 52 % (95 %CI:34-66) 14 days-3 months post-dose 2, 42 % (29-52) > 6 months post-dose 2, 71 % (64-77) 14 days-3 months post-dose 3, and 68 % (52-79) 3-6 months post-dose 3. rVE was 49 % (38-57) 14 days-3 months post-dose 3 and 45 % (18-63) 3-6 months post-dose 3. For BA.5, aVE was 56 % (27-73) 3-6 months post-dose 2, 32 % (12-47) > 6 months post-dose 2, 70 % (61-78) 14 days-3 months post-dose 3, 59 % (48-68) 3-6 months post-dose 3, 50 % (29-64) > 6 months post-dose 3, and 74 % (61-83) ≥ 14 days post-dose 4. rVE was 56 % (45-65) 14 days-3 months post-dose 3, 39 % (27-48) 3-6 months post-dose 3, 25 % (-2-45) > 6 months post-dose 3, and 30 % (-6-54) ≥ 14 days post-dose 4. CONCLUSIONS: Booster doses initially provided high protection against BA.5 at a level similar to that against BA.1/BA.2. However, the protection seemed shorter-lasting against BA.5, which likely contributed to the surge. Furthermore, rVE post-dose 4 was low even among recent vaccinees. These results support the introduction of variant-containing vaccines and emphasize the need for vaccines with longer duration of protection.

[Three cases with high TARC levels of gastrointestinal food allergies in neonates and infants].

We measured serum TARC (Thymus and activation-regulated chemokine, CCL-17) levels in three patients of gastrointestinal food allergies in neonates and infants. Patient 1: 14-day-old girl. The chief complaints were poor feeding and weight loss. She tested peripheral eosinophilia (5820 /µL), high serum TARC levels (4730 pg/mL) and positive milk-specific IgE (1.53 UA/mL) at the time of onset. After change from cow' milk formula to hydrolyzed infant formulas and breast milk ahead of dairy products intake, the symptoms resolved. One month and a half later, she re-tested negative milk-specific IgE and normal serum TARC levels (198 pg/mL). Patient 2: 3-month-old girl. The chief complaint was vomiting after intake of cow' milk formula. She tested negative milk-specific IgE and very high serum TARC levels (25200 pg/mL) at the time of onset. After changing to hydrolyzed infant formulas and breast milk ahead of dairy products intake, the symptom resolved. Three months later, she re-tested positive milk-specific IgE (0.42 UA/mL) and normal serum TARC levels (1250 pg/mL). Patient 3: 21-day-old boy. The chief complaint was vomiting after intake of cow' milk formula. He tested peripheral eosinophilia (2923 /µL), very high serum TARC levels (49100 pg/mL) and positive milk-specific IgE (0.47 UA/mL) at the time of onset. After changing to hydrolyzed infant formulas and breast milk ahead of dairy products intake, the symptom resolved. Two weeks later, he re-tested negative milk-specific IgE and serum TARC levels (2210 pg/mL). Serum TARC may be related to the part of gastrointestinal food allergies in neonates and infants.

Behavioral factors associated with SARS-CoV-2 infection in Japan.

BACKGROUND: The relative burden of COVID-19 has been less severe in Japan. One reason for this may be the uniquely strict restrictions imposed upon bars/restaurants. To assess if this approach was appropriately targeting high-risk individuals, we examined behavioral factors associated with SARS-CoV-2 infection in the community. METHODS: This multicenter case-control study involved individuals receiving SARS-CoV-2 testing in June-August 2021. Behavioral exposures in the past 2 weeks were collected via questionnaire. SARS-CoV-2 PCR-positive individuals were cases, while PCR-negative individuals were controls. RESULTS: The analysis included 778 individuals (266 [34.2%] positives; median age [interquartile range] 33 [27-43] years). Attending three or more social gatherings was associated with SARS-CoV-2 infection (adjusted odds ratio [aOR] 2.00 [95% CI 1.31-3.05]). Attending gatherings with alcohol (aOR 2.29 [1.53-3.42]), at bars/restaurants (aOR 1.55 [1.04-2.30]), outdoors/at parks (aOR 2.87 [1.01-8.13]), at night (aOR 2.07 [1.40-3.04]), five or more people (aOR 1.81 [1.00-3.30]), 2 hours or longer (aOR 1.76 [1.14-2.71]), not wearing a mask during gatherings (aOR 4.18 [2.29-7.64]), and cloth mask use (aOR 1.77 [1.11-2.83]) were associated with infection. Going to karaoke (aOR 2.53 [1.25-5.09]) and to a gym (aOR 1.87 [1.11-3.16]) were also associated with infection. Factors not associated with infection included visiting a cafe with others, ordering takeout, using food delivery services, eating out by oneself, and work/school/travel-related exposures including teleworking. CONCLUSIONS: We identified multiple behavioral factors associated with SARS-CoV-2 infection, many of which were in line with the policy/risk communication implemented in Japan. Rapid assessment of risk factors can inform decision making.

SARS-CoV-2 Omicron-neutralizing memory B cells are elicited by two doses of BNT162b2 mRNA vaccine.

Multiple SARS-CoV-2 variants have mutations in the spike receptor binding domain (RBD) with potential to evade neutralizing antibody. In particular, the Beta and Omicron variants escape from antibody neutralizing activity in those who received two doses of BNT162b2 mRNA vaccine. Nonetheless, boosting with a third vaccine dose or by breakthrough infection improves the overall breadth of the neutralizing antibodies, but the mechanism remains unclear. Here, we longitudinally profiled the cellular composition of RBD-binding memory B cell subsets and their antibody binding and neutralizing activity against SARS-CoV-2 variants after the second dose of mRNA vaccine. Two doses of the mRNA vaccine elicited plasma neutralizing antibodies with a limited activity against Beta and Omicron but induced an expanded antibody breadth overtime, up to 4.9 months after vaccination. In contrast, more than one-third of RBD-binding IgG+ memory B cells with a resting phenotype initially bound the Beta and Omicron variants and steadily increased the B cell receptor breadth overtime. As a result, a fraction of the resting memory B cell subset secreted Beta and Omicron-neutralizing antibody when stimulated in vitro. The neutralizing breadth of the resting memory B cell subset helps us understand the prominent recall of Omicron-neutralizing antibodies after an additional booster or breakthrough infection in fully vaccinated individuals.

Rapid discrimination of oseltamivir-resistant 275Y and -susceptible 275H substitutions in the neuraminidase gene of pandemic influenza A/H1N1 2009 virus by duplex one-step RT-PCR assay.

Pandemic influenza A/H1N1 2009 (A/H1N1pdm) virus caused significant outbreaks worldwide last year (2009). A number of oseltamivir-resistant A/H1N1pdm viruses possessing an H275Y substitution in the neuraminidase (NA) protein were reported sporadically in several countries, including Japan, but they were sensitive to zanamivir and did not spread in the community. In this study, to monitor rapidly and simply oseltamivir-resistant A/H1N1pdm viruses possessing H275Y, a duplex one-step RT-PCR assay (H275Y RT-PCR assay) was developed based on an endpoint genotyping analysis method. H275Y RT-PCR assay evaluated using several subtypes/types of influenza A and B viruses and other respiratory pathogenic viruses and shown to have high sensitivity and high specificity. Forty-four clinical specimens were tested after RNA purification using the H275Y RT-PCR assay, resulting in one clinical specimen being found to contain a virus possessing the H275Y mutation. Seventy-three clinical isolates were then tested with the H275Y assay by using clinical isolates in the cultured supernatants of cells directly, without RNA purification, and the results were consistent with the NA sequencing. Since the H275Y RT-PCR assay could detect the H275Y mutation in clinical isolates without RNA purification, as well as a H275Y mutated virus in clinical specimens after RNA purification, the assay was considered a powerful tool for surveillance screening of oseltamivir-resistant A/H1N1pdm virus activity.

Mobile and accurate detection system for infection by the 2009 pandemic influenza A (H1N1) virus with a pocket-warmer reverse-transcriptase loop-mediated isothermal amplification.

The 2009 pandemic H1N1 influenza A virus spread quickly worldwide in 2009. Since most of the fatal cases were reported in developing countries, rapid and accurate diagnosis methods that are usable in poorly equipped laboratories are necessary. In this study, a mobile detection system for the 2009 H1N1 influenza A virus was developed using a reverse-transcriptase loop-mediated isothermal amplification (RT-LAMP) kit with a disposable pocket-warmer as a heating device (designated as pwRT-LAMP). The pwRT-LAMP can detect as few as 100 copies of the virus--which is nearly as sensitive as real-time reverse-transcription polymerase chain reaction (RT-PCR)--and does not cross-react with RNA of seasonal influenza viruses. To evaluate the usefulness of the pwRT-LAMP system, nasal swab samples were collected from 56 patients with flu-like symptoms and were tested. Real-time RT-PCR confirmed that the 2009 H1N1 influenza A virus was present in 27 of the 56 samples. Of these 27 positive samples, QuickVue Influenza A+B immunochromatography detected the virus in only 11 samples (11/27; 40.7%), whereas the pwRT-LAMP system detected the virus in 26 of the 56 samples (26/27 of the positive samples; 96.3%). These findings indicate that the mobile pwRT-LAMP system is an accurate diagnostic system for the 2009 H1N1 influenza A virus, and has great potential utility in diagnosing future influenza pandemics.

Leucine-rich alpha-2-glycoprotein 1 and angiotensinogen as diagnostic biomarkers for Kawasaki disease.

OBJECTIVE: Kawasaki disease (KD) is a systemic vasculitis in childhood that can lead to coronary artery lesions (CALs). Although early diagnosis and treatment is important for preventing KD patients from development of CALs, diagnosis depends on the clinical features of KD. We studied the usefulness of leucine-rich alpha-2-glycoprotein 1 (LRG1) and angiotensinogen (AGT), previously reported as KD-related proteins, for KD diagnosis and estimation of intravenous immunoglobulin (IVIG) efficacy. METHODS: We undertook a prospective cohort study with patients having two or more KD symptoms in multiple centers in Japan, between July 2017 and February 2019. RESULTS: Two hundred forty-two patients were included. In multivariable analysis, one unit increase in LRG1 was associated with higher odds of KD diagnosis (Odds ratio [OR] 1.02 [95% confidence interval (CI) 1.001-1.03]). Double-positivity for AGT (≥ 26 µg/mL) and LRG1 (≥ 123.5 µg/mL) was an independent biomarker for KD diagnosis in both the total cohort and the subgroup of patients with two to four KD symptoms (OR 5.01 [95% CI 1.86-13.50] and 3.71 [95% CI 1.23-11.16], respectively). There was no association between LRG1/AGT and IVIG efficacy. CONCLUSION: Double-positivity for LRG1 and AGT is an biomarker for KD diagnosis, especially useful in diagnosing incomplete KD from non-KD. Future studies with larger cohorts should seek to determine whether LRG1 and AGT are valuable as definitive data referred at the diagnosis of KD and for estimating the risk of CALs.

Publisher Correction: Clinical evaluation of fully automated molecular diagnostic system "Simprova" for influenza virus, respiratory syncytial virus, and human metapneumovirus.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Clinical evaluation of fully automated molecular diagnostic system "Simprova" for influenza virus, respiratory syncytial virus, and human metapneumovirus.

Influenza virus, respiratory syncytial virus, and human metapneumovirus commonly cause acute upper and lower respiratory tract infections, especially in children and the elderly. Although rapid antigen detection tests for detecting these infections have been introduced recently, these are less sensitive than nucleic acid amplification tests. More recently, highly sensitive point-of-care testings (POCTs) have been developed based on nucleic acid amplification tests, which are easy to use in clinical settings. In this study, loop-mediated isothermal amplification (LAMP)-based POCT "Simprova" to detect influenza A and B viruses, respiratory syncytial virus, and human metapneumovirus was developed. Simprova system is fully automated and does not require skilled personnel. In addition, positive results can be achieved faster than with PCR. In this study, the accuracy of the POCT was retrospectively analyzed using 241 frozen stocked specimens. Additionally, the usability of the Simprova at clinical sites was assessed in a prospective clinical study using 380 clinical specimens and compared to those of real-time PCR and rapid antigen detection test. The novel LAMP-based POCT demonstrated high sensitivity and specificity in characterizing clinical specimens from patients with influenza-like illnesses. The Simprova is a powerful tool for early diagnosis of respiratory viral infections in point-of-care settings.