[Diagnostic value of rapid antigen testing for the detection of SARS-CoV-2 infection].

Objective: To investigate the diagnostic value of rapid antigen test based on colloidal gold immunochromatographic assay for the detection of SARS-CoV-2 infection in symptomatic patients. Methods: From May 20 to June 5 2022, 76 hospitalized children and their 55 accompanying family members with confirmed SARS-CoV-2 infection in the COVID-19 isolation unit of the Children's Hospital of Fudan University (designated referral hospital for SARS-CoV-2 infection in Shanghai) enrolled. Their nasopharyngeal swab specimens were consecutively collected. The samples were tested for SARS-CoV-2 nucleic acid by real-time quantitative. SARS-CoV-2 antigen was tested by immunochromatography. The correlation between the antigen detection results and the change of the cycle threshold (Ct) values were evaluated, as well as the sensitivity and specificity of SARS-CoV-2 antigen detection at different periods after the onset of the disease. Kappa consistency test was conducted to investigate the consistency between the 2 diagnostic methods. Results: Of the enrolled SARS-CoV-2 symptomatic infections, 76 were children, including 41 males and 35 females, with an age of 5 (2, 9) years; 55 were accompanying families, including 8 males and 47 females, with an age of 38 (32, 41) years. All 478 samples were simultaneously tested for SARS-CoV-2 antigen and nucleic acid. In any period from disease onset to negative conversion of viral nucleic acid, the overall sensitivity of the rapid antigen test was 48.2% (119/247), the specificity was 98.3% (227/231), and antigen test and nucleic acid test showed moderate consistency (κ=0.46, P<0.05). The sensitivity of antigen test was 100% (82/82) when the Ct value was ≤25. And the sensitivity of antigen test was 8/10, 4/15 and 8.3% (3/36) when the Ct value was 26, 30 and 35, respectively. All antigen tests were negative when Ct value was >35. During the period of 1-2 days, 3-5 days, 6-7 days, 8-10 days and >10 days after onset, the sensitivity and specificity of SARS-CoV-2 antigen test were 5/8 and 5/5, 90.2% (37/41) and 5/5, 88.9% (24/27) and 2/5, 45.0% (36/80) and 94.1% (32/34), 18.7% (17/91) and 98.9% (183/185) respectively. The Ct values of nasopharyngeal swabs were<26 during 2 to 7 days after onset, 28.7±5.0 on day 8, 34.5±2.9 on day 13 and > 35 after 14 days, respectively. Conclusion: SARS-CoV-2 antigen test in the patients with SARS-CoV-2 infection shows acceptable sensitivity and specificity within 7 days after onset of disease, and the sensitivity was positively correlated with viral load and negatively correlated with onset time.

[Clinical characteristics of 16 neonates infected with SARS-CoV-2 during Omicron variant outbreak].

Objective: To analyze the clinical characteristics of the neonates infected with SARS-CoV-2 during the Omicron outbreak in Shanghai 2022. Methods: In this retrospective case series study, all the 16 neonates with SARS-CoV-2 Omicron infection who were admitted to the neonatal unit in Shanghai Public Health Clinical Center from March 1st to May 31st, 2022 were enrolled. Their epidemiological history, clinical manifestations, nucleic acid cycle threshold (Ct) value and outcomes were analyzed. Based on maternal vaccination, they were divided into vaccinated group and unvaccinated group. Rank sum test and Chi-square test were used for the comparison between the groups. Results: Among the 16 neonates, 10 were male, and 6 were female. All the infants were full-term. The infection was confirmed at the age of 12.5 (8.0, 20.5) days. All the neonates had a history of exposure to infected family members, and thus horizontal transmission was the primary mode. Four infants were asymptomatic, 12 were symptomatic, and there were no severe or critical cases. The most common clinical manifestation was fever (11 cases), with the highest temperature of 38.1 (37.9, 38.3) ℃ and a course of 1-5 days. Other clinical manifestations included nasal obstruction (3 cases), runny nose (2 cases), cough (2 cases), poor feeding (2 cases), vomiting (1 case), and mild tachypnea (1 case). The complete blood counts of all neonates were within the normal range, and the C-reactive protein increased slightly in 1 infant. Chest imaging was performed in 2 infants, showing mild focal exudative changes. Nucleic acid turned negative (Ct value ≥35) within 7-15 days after diagnosis. All neonates fully recovered after supportive treatment, and the length of hospitalization was 13 (10, 14) days. In the telephone follow-up 2 weeks after discharge for all 16 cases, no infant showed reoccurrence of clinical manifestations or nucleic acid reactivation. Maternal vaccination was not significantly correlated with symptomatic infection or the persistence of positive nucleic acid result in neonates (all P>0.05). Conclusions: Horizontal transmission is the primary mode for neonatal SARS-CoV-2 Omicron infection. Neonatal infections are usually mild or asymptomatic, with good short-term outcomes. And their clinical manifestations and laboratory examinations are nonspecific.

[Clinical analysis of liver chemistries in children and adolescent with 2019-nCoV infection].

Objective: To describe the clinical features of liver involvement in children and adolescent with 2019-nCoV infection. Methods: The clinical data of 77 hospitalized cases admitted to the Children's Hospital of Fudan University were collected from January 19 to November 28, 2020. The characteristics and risk factors of abnormal liver chemistries in children with laboratory-confirmed 2019-nCoV infection were analyzed. Results: Of the 77 cases, 44 were male (57.1%) and 33 were female (42.9%), with a median age of 10 years. 27(35.1%) were asymptomatic, 28(36.4%) had mild illness, 22(28.6%)had non-severe pneumonia. Hydroxychloroquine was used in 7 cases. Of the 75 children without underlying diseases, alanine aminotransferase was elevated in 1 case (1.5%, during hydroxychloroquine therapy), aspartate aminotransferase was elevated in 7 cases (10.3%), alkaline phosphatase was elevated in 7 cases (28%), and total bilirubin, direct bilirubin, albumin, international normalized ratio were in normal range. There was no statistical difference between the pneumonia group and the non-pneumonia group in term of liver chemistries (P > 0.05), same as between the elevated erythrocyte sedimentation rate group and the normal group. There was no aggravation of liver injury in the child with biliary atresia. The child with epilepsy showed no abnormal liver chemistries after infection. Conclusion: Children with 2019-nCoV infection had mild clinical symptoms with few cases of liver injury. The abnormal liver chemistries in children with COVID-19 infection may be related to the underlying disease and the use of antiviral drugs.