Clinical evaluation of DIAGNOVIR SARS-CoV-2 ultra-rapid antigen test performance compared to PCR-based testing.

Coronavirus Disease-19 (COVID-19) is a highly contagious infectious disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The development of rapid antigen tests has contributed to easing the burden on healthcare and lifting restrictions by detecting infected individuals to help prevent further transmission of the virus. We developed a state-of-art rapid antigen testing system, named DIAGNOVIR, based on immune-fluorescence analysis, which can process and give the results in a minute. In our study, we assessed the performance of the DIAGNOVIR and compared the results with those of the qRT-PCR test. Our results demonstrated that the sensitivity and specificity of the DIAGNOVIR were 94% and 99.2%, respectively, with a 100% sensitivity and 96.97% specificity, among asymptomatic patients. In addition, DIAGNOVIR can detect SARS­CoV­2 with 100% sensitivity up to 5 days after symptom onset. We observed that the DIAGNOVIR Rapid Antigen Test's limit of detection (LoD) was not significantly affected by the SARS­CoV­2 variants including Wuhan, alpha (B1.1.7), beta (B.1.351), delta (B.1.617.2) and omicron (B.1.1.529) variants, and LoD was calculated as 8 × 102, 6.81 × 101.5, 3.2 × 101.5, 1 × 103, and 1 × 103.5 TCID50/mL, respectively. Our results indicated that DIAGNOVIR can detect all SARS-CoV-2 variants in just seconds with higher sensitivity and specificity lower testing costs and decreased turnover time.

Comparison of a novel antigen detection test with reverse transcription polymerase chain reaction assay for laboratory diagnosis of SARS-CoV-2 infection.

Molecular diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by real-time reverse transcription polymerase chain reaction (RT-PCR) in respiratory specimens is considered the gold standard method. This method is highly sensitive and specific but it has some limitations such as being expensive and requiring special laboratory equipment and skilled personnel. RapidFor™ Antigen Rapid Test Kit is a commercially available Ag-RDT which is produced in Turkey and designed to detect the nucleocapsid antigen of SARS-CoV-2 in nasopharyngeal swab samples. The aim of this study was to evaluate the performance of this novel SARS-CoV-2 antigen detection considering the RT-PCR method as the gold standard. Four hundred forty-four nasopharyngeal swab samples which were collected from the patients who met clinical criteria of COVID-19 from ten centers in Turkey between September 2020 and February 2021 were included in the study. All the nasopharyngeal swab samples were tested for SARS-CoV-2 RNA using commercial RT-PCR kits (Bioeksen and A1 Lifesciences, Istanbul, Turkey) according to the manufacturer's instructions. Viral loads were assessed according to the cycle threshold (Ct) values. RapidFor™ SARS-CoV-2 antigen test (Vitrosens Biotechnology, Istanbul, Turkey) was used to investigate the presence of SARS-CoV-2 antigen in all samples following the manufacturer's instructions. Out of 444 nasopharyngeal swab samples tested, 346 (77.9%) were positive and 98 (22.1%) were negative for SARS-CoV-2 RNA by RTPCR. Overall sensitivity of the RapidFor™. Antigen Rapid Test Kit was 80.3% whereas specificity was found to be 87.8%. Positivity rate of rapid antigen test in samples with Ct values over 25 and below 30 was 82.7%, while it increased to 95.7% in samples 20 ≤ Ct < 25 and reached 100% in samples with Ct values below 20. RapidFor™ SARS-CoV-2 Ag test might be a good choice in the screening of symptomatic and asymptomatic patients and their contacts for taking isolation measures early, with advantages over RT-PCR as being rapid, easy and being applicable in every laboratory and even at point of care.

Antibody response to two doses of inactivated SARS-CoV-2 vaccine (CoronaVac) in kidney transplant recipients.

BACKGROUND: Coronavirus Disease-19 (COVID-19) has high mortality in kidney transplant recipients (KTR), and vaccination against severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) is vital for this population. Although the humoral response to messenger RNA vaccines was shown to be impaired in KTR, there is a lack of data regarding the antibody response to inactivated vaccines. We investigated the antibody response to two consequent doses of the inactivated SARS-CoV-2 vaccine (CoronaVac; Sinovac Biotech, China). METHODS: A total of 118 patients from two centers were included. The levels of anti-SARS-CoV-2 immunoglobulin-G antibodies against the nucleocapsid and spike antigens were determined with enzyme immunoassay (DIA.PRO; Milano, Italy) before the vaccine and one month after the second dose of the vaccine. Thirty-three patients were excluded due to antibody positivity in the serum samples obtained before vaccination. RESULTS: Eighty-five patients, 47 of whom were female, with a mean age of 46 ± 12, were included in the statistical analysis. The maintenance immunosuppressive therapy comprised tacrolimus (88.2%), mycophenolate (63.6%), and low-dose steroids (95.3%) in the majority of the patients. After a median of 31 days following the second dose of the vaccine, only 16 (18.8%) patients developed an antibody response. The median (IQR) antibody level was 52.5 IU/ml (21.5-96). Age (48 vs. 38, p = .005) and serum creatinine levels (1.14 vs. 0.91, p = .04) were higher in non-responders and were also found to be independently associated with the antibody response (odds ratio (OR): 0.93, p = 0.012 and 0.15, p = 0.045, respectively) in multivariate analysis. CONCLUSION: In this study, we found the antibody response to the inactivated vaccine to be considerably low (18.8%) in KTR. Increased age and impaired renal function were associated with worse antibody response. Based on the knowledge that mRNA vaccines yield better humoral responses, this special population might be considered for additional doses of mRNA vaccination.

An unusual course of SARS-CoV-2 infection: Challenging diagnosis of Guillain-Barré Syndrome.

COVID-19, caused by severe acute respiratory syndrome coronavirus-2, typically presents with respiratory symptoms and fever, but still a variety of clinical presentations have been reported. In this study, it was aimed to report a case of COVID-19 with an atypical presentation and an atypical course. As well, the recovery phase was complicated with GBS and consequently cytomegalovirus infection. It should be kept in mind that patients with COVID-19 severe disease need to be followed for neurological and other complications which may arise during the course of critical illness.

Successful treatment of COVID-19 infection in a patient with tracheostomy.

Coronavirus disease 2019 (COVID-19) has been demonstrated to be the cause of emerging atypical pneumonia. In patients with tracheostomy, coronavirus hypothetically coexists with well-known bacterial agents. A 61-year-old male patient with tracheostomy was admitted to the hospital with dyspnea, fever and increased tracheal secretions. Laboratory findings revealed lymphopenia and elevated C-reactive protein and procalcitonin levels. Chest computed tomography showed consolidation areas and ground-glass opacities more prominent in subpleural areas. Although; two consecutive RT-PCR analyses of combined nasopharengeal/oropharengeal swabs were found to be negative for SARS-CoV-2 RNA, positivity was reported for endotracheal aspirate (ETA) sample. Significant growth of Pseudomonas aeruginosa and Stenotrophomonas maltophilia was detected in the bacterial culture of ETA sample. In conclusion, clinical samples for SARS-CoV-2 should be obtained through the lower respiratory tract, if possible and if upper airway samples are negative. To the best our knowledge, our paper is the first report of the patient with tracheostomy who was treated successfully for COVID-19.

The incidence and clinical effects of Bordetella pertussis in children hospitalized with acute bronchiolitis.

BACKGROUND: Pertussis is a disease leading to high morbidity and mortality in neonates and infants. Bronchiolitis is the most common cause of hospitalization especially in children < 2 year-old. Although the clinical findings are different in these two diseases, it is sometimes difficult to make this distinction in partially or fully vaccinated children. This study aimed to identify the incidence, clinical and laboratory effects of B. pertussis as a causative agent in hospitalized children with acute bronchiolitis. METHODS: The study included patients diagnosed with acute bronchiolitis and admitted to the Division of Pediatric Infectious Diseases from January 2012 to December 2015, aged 24 months or younger, evaluated for viruses and bacteria with polymerase chain reaction in respiratory tract secretions. RESULTS: The study included 380 patients hospitalized with acute bronchiolitis. Of these patients, 85.8% were identified to be positive for at least one respiratory pathogen. The most commonly identified pathogens were respiratory syncytial virus (RSV) A/B, rhinovirus, parainfluenza virus, adenovirus, bocavirus and metapneumovirus A/B. B. pertussis was only detected in 5 patients (1.5%). In the patients with B. pertussis identified, coinfection with another virus was observed including rhinovirus (n= 2), influenza A virus (n= 1), coronavirus OC43 (n= 1) and RSV A/B (n= 1). The presence of B. pertussis did not appear to cause any significant clinical or laboratory differences in patients. CONCLUSIONS: B. pertussis is a rare pathogen in patients admitted to hospital for acute bronchiolitis. However, in patients who do not respond to standard bronchiolitis treatment, B. pertussis should be considered as a causative agent. Early identification of this pathogen is important in terms of quarantining the patient, administering appropriate antimicrobial treatment, and prophylactic treatment to household and other close contacts.