Surveillance of SARS-CoV-2 Antibody of Patients in Local Affected Area During the Lockdown (preprint)

Background: Serosurvalence is crucial in estimating the range of SARS-CoV-2 infections, predicting the possibility of another wave, and decide on a vaccination strategy. To understand the herd immunity after the COVID-19 pandemic, the seroprevalence was measured in 3062 individuals with or without COVID-19. Methods: The levels of SARS-CoV-2 antibody IgM and IgG were measured by the immuno-colloidal gold method.Results: The mean seroprevalence for IgM and IgG in all participants was 2.81% and 7.51%, respectively. The positive rate of IgG was significantly higher in women than in men (P<0.05). The highest positive rate of IgM was observed in 41-60 years of age (3.49%), while the highest seroprevalence for IgG was observed in persons >60 years of age (8.61%). The positive rates of IgM and IgG in the convalescent patients were 31.82% and 77.27%, respectively, which was significantly higher than individuals with suspected syndromes or individuals without any clinical signs (P<0.01). Seroprevalence for IgG in medical staff was markedly higher than those in residents. The seroprevalence in patients with various comorbidity was no significant difference (P>0.05).Conclusions: The low positive rate of the SARS-CoV-2 IgM and NA test indicated that the SARS-CoV-2 outbreak is subsiding after three months, and the possibility of reintroduction of the virus from an unidentified natural reservoir is low. Seroprevalence provides the information for humoral immunity and vaccine in the future.

Environmental contamination of the SARS-CoV-2 in healthcare premises: An urgent call for protection for healthcare workers (preprint)

Importance A large number of healthcare workers (HCWs) were infected by SARS-CoV-2 during the ongoing outbreak of COVID-19 in Wuhan, China. Hospitals are significant epicenters for the human-to-human transmission of the SARS-CoV-2 for HCWs, patients, and visitors. No data has been reported on the details of hospital environmental contamination status in the epicenter of Wuhan. Objective To investigate the extent to which SARS-CoV-2 contaminates healthcare settings, including to identify function zones of the hospital with the highest contamination levels and to identify the most contaminated objects, and personal protection equipment (PPE) in Wuhan, China. Design A field investigation was conducted to collect the surface swabs in various environments in the hospital and a laboratory experiment was conducted to examine the presence of the SARS-CoV-2 RNA. Setting Six hundred twenty-six surface samples were collected within the Zhongnan Medical Center in Wuhan, China in the mist of the COVID-19 outbreak between February 7 - February 27, 2020. Participants Dacron swabs were aseptically collected from the surfaces of 13 hospital function zones, five major objects, and three major personal protection equipment (PPE). The SARS-CoV-2 RNAs were detected by reverse transcription-PCR (RT-PCR). Main Outcomes and Measures SARS-CoV-2 RNAs Results The most contaminated zones were the intensive care unit specialized for taking care of novel coronavirus pneumonia (NCP) (31.9%), Obstetric Isolation Ward specialized for pregnant women with NCP (28.1%), and Isolation Ward for NCP (19.6%). We classified the 13 zones into four contamination levels. The most contaminated objects are self-service printers (20.0%), desktop/keyboard (16.8%), and doorknob (16.0%). Both hand sanitizer dispensers (20.3%) and gloves (15.4%) were most contaminated PPE. Conclusions and Relevance Many surfaces were contaminated with SARS-CoV-2 across the hospital in various patient care areas, commonly used objects, medical equipment, and PPE. The 13 hospital function zones were classified into four contamination levels. These findings emphasize the urgent need to ensure adequate environmental cleaning, strengthen infection prevention training, and improve infection prevention precautions among HCWs during the outbreak of COVID-19. The findings may have important implications for modifying and developing urgently needed policy to better protect healthcare workers during this ongoing pandemic of SARS-CoV-2.

Analysis of false-negative results for 2019 novel coronavirus nucleic acid test and related countermeasures / 中华检验医学杂志

In December 2019, a cluster of patients with pneumonia of unknown cause were linked to a seafood wholesale market in Wuhan, China. Some studies found that the virus was a new kind of virus which had never been found in the human body. Then, the virus was named 2019 Novel Coronavirus (2019-nCoV) by the World Health Organization (WHO). 2019-nCoV nucleic acid detection is one of the essential indicators of NCP (Novel Coronavirus Pneumonia). Recently, some false-negative cases in China-Japan Friendship Hospital and Hangzhou Hospital led the clinical doctors to question the value of the nucleic acid detection. In this paper, more than 3 000 results of 2019-nCoV detection in Zhongnan Hospital, Wuhan University were analyzed. Attention should be paid to the root cause of false-negative results and the related countermeasures should be taken.

Can routine laboratory tests discriminate 2019 novel coronavirus infected pneumonia from other community-acquired pneumonia? (preprint)

Background. The clinical presentation of 2019 Novel Coronavirus (2019-nCov) infected pneumonia (NCIP) resembles that of other etiologies of community-acquired pneumonia (CAP). We aimed to identify clinical laboratory features to distinguish NCIP from CAP. Methods. We compared the ability of the hematological and biochemical features of 84 patients with NCIP at hospital admission and 316 patients with CAP. Parameters independently predictive of NCIP were calculated by multivariate logistic regression. The receiver operating characteristic (ROC) curves were generated and the area under the ROC curve (AUC) was measured to evaluate the discriminative ability. Results. Most hematological and biochemical indexes of patients with NCIP were significantly different from patients with CAP. Nine laboratory parameters were identified to be highly predictive of a diagnosis of NCIP by multivariate analysis. The AUCs demonstrated good discriminatory ability for red cell distribution width (RDW) with an AUC of 0.88 and Hemoglobin (HGB) with an AUC of 0.82. Red blood cell (RBC), albumin (ALB), eosinophil (EO), hematocrit (HCT), alkaline phosphatase (ALP), and white blood cell (WBC) had fair discriminatory ability. Combinations of any two parameters performed better than did the RDW alone. Conclusions. Routine laboratory examinations may be helpful for the diagnosis of NCIP. Application of laboratory tests may help to optimize the use of isolation rooms for patients when they present with unexplained febrile respiratory illnesses.