Analysis on the household secondary attack rates of the SARS-CoV-2 Delta variant and the associated factors / 中华预防医学杂志

Objective: To evaluate the household secondary attack rates of the SARS-CoV-2 Delta variant and the associated factors. Methods: A COVID-19 outbreak caused by the Delta variant occurred in Nanjing in July 2021. A total of 235 cases with current addresses in Nanjing were reported from 171 households. The subjects in this study were selected from household close contact(s) of infected cases. The information on household index cases and their contacts were collected, and the household secondary attack rate (HSAR) and the risk factors were analyzed by the multi-factor logistic regression model. Results: A total of 234 cases of household close contacts and 64 household secondary cases were reported from 103 households, and the HSAR was 27.4% (64/234, 95%CI:22.0% to 33.4%). The proportions of household size for 2 to 3, 4 to 5, and 6 to 9 were 64.1% (66), 26.2% (27) and 9.7% (10), respectively. A total of 35 cases of household cluster outbreaks were reported (35/103, 34.0%). The number of the first case in the household (FCH) was 103 and males accounted for 27.2% (28 cases), with the median age (Q1, Q3) of 49 (9, 56). The number of household close contacts was 234 and males accounted for 59.0% (138 cases), with the median age (Q1, Q3) of 42 (20, 55) and the median exposure period (Q1, Q3) of 3 (1, 3) days. The multi-factor logistic regression model showed that the higher HSAR was observed in the FCH with the features of airport staff (OR=2.913, 95%CI:1.469-5.774), detection from home quarantine screening (OR=6.795, 95%CI:1.761-26.219) and detection from mass screening (OR=4.239, 95%CI:1.098-16.368). Meanwhile, higher HSAR was observed in cases with longer household exposure (OR=1.221, 95%CI:1.040-1.432), non-vaccination (OR=2.963, 95%CI:1.288-6.813) and incomplete vaccinations (OR=2.842, 95%CI:0.925-8.731). Conclusion: The generation interval of the Delta variant is shortened, and the ability of transmission within the household is enhanced. In the outbreak in Nanjing, the associated factors of HSAR are occupation, detection route, vaccination and exposure period.

Detection of lymph node of rabbit thyroid by real-time fluorescence imaging / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To detect the lymph nodes (LN) of rabbit thyroid by fluorescence imaging and to provide experimental evidence for its clinical application.</p><p><b>METHODS</b>Each of 50 lateral thyroid lobes of 25 rabbits was injected with 0.02 ml of indocyanine green (ICG), and 0.02 ml methylene followed. ICG fluorescence was detected using photodynamic eye (PDE). The methylene staining in LN was also observed. The onset time of ICG staining in LN was measured.</p><p><b>RESULTS</b>The detection rate of fluorescence imaging and blue dye imaging were respectively 86.0% (43/50) and 66.0% (33/50), with a significant difference (P = 0.034), and the accuracy were respectively 85.5% (53/62) and 70.7% (41/58). The onset time (x(-) ± s) of ICG staining in LN was (118.3 ± 16.1) s.</p><p><b>CONCLUSIONS</b>Fluorescence imaging showed satisfied detection rate and accuracy. The detection rate of LN by fluorescence imaging was higher than that by blue dye imaging. Fluorescence imaging could be an alternative method for the detection of LN of thyroid in future clinical practice.</p>