[Clinical characteristics in patients with persistent positive pharyngeal swab of omicron variant and analysis on nucleic acid testing of anal swabs].

OBJECTIVE: To analyze the clinical characteristics in patients with persistent positive pharyngeal swab of 2019 novel coronavirus Omicron variant and results of nucleic acid testing of anal swabs to provide basis for prevention and control measures. METHODS: This study included 93 patients whose pharyngeal swab nucleic acid test were persistent positive and admitted to the ward of Daping Hospital in the National Exhibition and Convention Center (Shanghai) Makeshift Hospital from May 1 to May 24, 2022. The gender, age, underlying diseases, vaccination status, clinical symptoms, interval between infection onset and anal sampling, length of hospital stay, the nucleic acid test result of pharyngeal swabs and anal swabs and the time turning negative were collected and analyzed. RESULTS: The age of 93 patients ranged from 8 to 72 years old with a median of (46.0±16.0) years old. Among them, 30 cases (32.3%) were male and 63 cases (67.7%) were female. Sixty-five patients (69.9%) received 2-3 shots of vaccine, 2 patients (2.1%) received 1 shot, and 26 patients (28.0%) did not receive any vaccination. Twenty patients (21.5%) had underlying diseases, of which hypertension (13 cases, 14.0%) and type 2 diabetes mellitus (6 cases, 6.5%) were the most common. Twenty-four patients (25.8%) had asymptomatic infection and the rest (69 cases, 74.2%) had mild symptoms. Cough (50 cases, 53.8%) and sore throat (28 cases, 30.1%) were the most common clinical manifestations of the upper respiratory tract in these patients. Only 6 patients (6.5%) had gastrointestinal symptoms (including diarrhea in 5 patients and diarrhea with vomiting in 1 patient). Pharyngeal and anal swabs were collected simultaneously from all 93 patients at 8-16th days [(11.55±2.27) days] after 2019 novel coronavirus Omicron variant infection. The pharyngeal swabs were positive in 79 patients (85.0%) and the anal swabs were positive in 5 patients (5.4%). The time of pharyngeal swabs turning negative was (14.7±2.9) days, and that of anal swab turning positive was (14.2±1.9) days. The median length of hospital stay was (16.7±2.9) days. CONCLUSIONS: In patients with persistent positive nucleic acid of the 2019 novel coronavirus Omicron variant, there were more mild infection than asymptomatic. The upper respiratory tract symptoms such as cough and sore throat were the most. The likelihood of transmission of 2019 novel coronavirus Omicron variant through the digestive tract may be low. The correlation between gastrointestinal symptoms and 2019 novel coronavirus Omicron variant RNA in the digestive tract is uncertain.

Evaluation of the presence of SARS-CoV-2 in vaginal and anal swabs of women with omicron variants of SARS-CoV-2 infection.

Objectives: The study aimed to determine whether SARS-CoV-2 Omicron variant could be detected in the vaginal fluid and anal swabs of reproductive-aged and postmenopausal women infected with SARS-CoV-2 Omicron variant. Methods: Included in this study were 63 women who were laboratory confirmed as having SARS-CoV-2 Omicron variant infection and admitted to the responsible ward of Daping Hospital of at the National Exhibition and Convention Center(Shanghai) Makeshift Hospital from May 1-24, 2022.From them, vaginal and anal swabs were obtained with informed consent. The demographic and baseline clinical characteristics and the swab test results were analyzed. Results: The 63 included patients ranged in age from 18 to 72 years with a median of 47.71 ± 15.21 years. Of them, 38 women (60.3%) were in their reproductive years. Most of the participants (77.8%) were healthy without significant underlying diseases. Fourteen patients (22.2%) had asymptomatic infection and the remaining 49 (77.8%) had mild infection. The upper respiratory tract symptoms including cough (40/63.5%) and sore throat (18/28.6%)were the most common clinical manifestations of these mildly infected patients. Only 5 patients (7.8%) had gastrointestinal (GI) symptoms, including simple diarrhea in 4 patients, and diarrhea with vomiting in one patient. Pharyngeal,vaginal and anal swabs were collected simultaneously from all 63 patients 8-16 (mean 11.25 ± 2.23) days after SARS-Cov-2 Omicron variant infection. The vaginal swabs were negative for SARS-CoV-2 in all 63 patients, and the anal swabs were positive in 4 patients (6.5%). The overall median hospitalization duration was 16.73 ± 3.16 days. Conclusion: The results of the present study suggest that there is a low possibility of SARS-Cov-2 Omicron variant transmission via the digestive tract and vaginal fluid. The correlation between the GI symptoms and the presence of viral RNA in anal swabs is uncertain.

Hydrophilic rhodamine B-loaded / boronic acid-modified graphene oxide nanocomposite as a substitute of enzyme-labeled second antibody for ultrasensitive detection of antibodies.

Enzyme-labeled secondary antibody is often used to amplify the output signal in the process of antibody detection. However, its preparation process is complex and time-consuming. Herein, we fabricated an innovative hydrophilic rhodamine B-loaded / boronic acid-modified graphene oxide (HRBGO) nanocomposite, used as a substitute of enzyme-labeled second antibody. The synthetic HRBGO was loaded with generous rhodamine B and modified with boronic acid. Therefore, the HRBGO could selectively label the carbohydrate chains of Fc fragment of primary antibody through specific boronate affinity recognition, and then perform signal output and amplification by releasing rhodamine B. To verify the practicability of HRBGO, trastuzumab as a humanized monoclonal antibody targeting human epidermal growth factor receptor-2 (HER2) was selected as model antibody. A glycosylation site-blocked / HER2-immobilized magnetic nanoparticles (GHMN) was also prepared for selectively capturing trastuzumab from complex samples via specific immunoaffinity. Because the glycosylation sites of HER2 can also be labeled with the HRBGO by boronate affinity recognition, these sites were blocked by a masking agent to minimize the background signal. For specific and ultrasensitive detection of trastuzumab, the integration of GHMN and HRBGO was proposed and optimized in detail. Trastuzumab detection based on HRBGO consisted of three steps: specific capture, selective labeling, and output signal. The proposed strategy provided ultrahigh sensitivity with limit of detection of 0.35 fg mL-1 and was successfully applied in the detection of trastuzumab in spiked serum sample with recovery and relative standard deviation in the range of 98.7-103.8% and 3.8-6.0%, respectively. To assess universal applicability, the HRBGO was also successfully used for the determination of anti-SARS-COV2 RBD antibody in human serum sample.