ABSTRACT
BackgroundThe Omicron variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), designated as a variant of concern by the World Health Organization, spreads globally and was confirmed as the cause of the Omicron wave of the coronavirus disease 2019 (COVID-19) pandemic in Shanghai, China. The viral shedding duration of Omicron variants needs to be determined. MethodsWe retrospectively analyzed 382 patients admitted to a shelter hospital for COVID-19. Of the patients, 8 patients were referred to a designated hospital, 100 were infected asymptomatic patients, and 274 patients had mild COVID-19. ResultsThe vaccination rates (including fully and boosted) in the asymptomatic and mild COVID-19 patients were 92.00% and 94.16%, respectively. Majority of the studied population showed a first reverse transcription-polymerase chain reaction cycle threshold (Ct) value of 20. For 2565 nasopharyngeal swabs from close or sub-close contacts, the Ct value gradually increased to 35 for 8 days, and the median duration of viral shedding time was 10 days after the first positive detection of the SARS-CoV-2 nuclei acid. ConclusionsQuantitative viral RNA load assays in COVID-19 (BA.2.2.1) close or sub-closed contacts could be used to prevent transmissions and control precautions.
ABSTRACT
Objective:To evaluate the detection accuracy of hepatitis B virus (HBV) serological markers among grassroots medical institutions in the demonstration areas of infectious diseases.Methods:A fixed sampling method was used among the followed-up hepatitis B cohort in general population of six infectious disease demonstration areas nationwide. Blood samples of chosen objects were collected, in which HBsAg and anti-HBs were tested by grassroots medical institutions and were also parallely tested by the third-party platform. The test results were compared between the two groups. Statistical analyses were conducted by SAS 9.4 software.Results:A total of 5 756 and 5 263 samples of HBsAg and anti-HBs were successfully tested, respectively. Comparing the results of HBsAg and anti-HBs from grassroots medical institutions with the results from the third platform, the agreement of HBsAg and anti-HBs was 97.13% and 77.33%, respectively. The Kappa value was 0.56 (95% CI 0.50-0.62) for HBsAg and 0.54 (95% CI 0.52-0.56) for anti-HBs, respectively; and the McNemar tests indicated the difference between the results (all P<0.01). There were also significant differences in agreement of testing results with the third platformin among different regions ( P<0.05 or <0.01). The Kappa values indicated that Jiangsu province and Guangdong province had high accordance rates of HBsAg (0.87 and 0.81, respectively), and Gansu province and Guangdong province had high accordance rates of anti-HBs (Both were 0.74). Regarding the results from the third platform as the standard, the sensitivity of HBsAg testing in grassroots medical institutions was moderate (40.51%) and the specificity was well (99.96%). The sensitivity of anti-HBs testing was substantial (73.18%) and the specificity was well (84.31%). Guangdong province (Youden index: 0.69) and Jiangsu province (Youden index: 0.80) had high identification ability for HBsAg, and for indicator of anti-HBs, Gansu province (Youden index: 0.78) and Guangdong province (Youden index: 0.76) had high identification ability. Conclusion:There are certain differences in results of HBV serological markers tests between the grassroots medical institutions in the demonstration areas of infectious diseases and the third platform. Current testing strategies in grassroots medical institutions are suitable for identifying people without hepatitis B infection, while it is necessary to pay attention to the situation of potential false negative error.
