ABSTRACT
This study aimed to investigate the effect of different environmental disinfection methods on reducing contaminated surfaces (CSs) by the Omicron BA.2.2 variant of SARS-CoV-2 in the fever clinic between March 20 and May 30, 2022, and to analyze the influences and related factors of CSs. This study includes survey data from 389 positive patients (SPPs) and 204 CSs in the fever clinic, including the CS type, disinfection method, length of time spent in the clinic, cycle threshold (CT) value, name, age, weight, mask type, mask-wearing compliance, hand-mouth touch frequency and sex. Associations between study variables and specified outcomes were explored using univariate regression analyses. Mask-wearing compliance had a significant negative correlation with CSs (r = - 0.446, P = 0.037). Among the 389 SPPs, 22 SPPs (CRP, 5.66%) caused CSs in the separate isolation room. A total of 219 SPPs (56.30%) were male. The mean age of SPPs was 4.34 ± 3.92 years old, and the mean CT value was 12.44 ± 5.11. In total, 9952 samples with exposure history were taken, including 204 (2.05%) CSs. Among the CSs, the positive rate of flat surfaces was the highest in public areas (2.52%) and separate isolation rooms (4.75%). Disinfection methods of ultraviolet radiation + chemical irradiation significantly reduced the CSs in both the public area (0% vs. 4.56%) and the separate isolation room (0.76% vs. 2.64%) compared with the chemical method alone (P < 0.05). Compared with ordinary SPPs, CRPs were older (6.04 year vs. 4.23 year), and the male proportion was higher (72.73% vs. 55.31%). In particular, it was found that SPPs contaminated their surroundings and therefore imposed risks on other people. Environmental disinfection with ultraviolet radiation + chemical treatment should be emphasized. The findings may be useful to guide infection control practices for the Omicron BA.2.2 variant of SARS-CoV-2.
Subject(s)
COVID-19 , SARS-CoV-2 , Humans , Male , Infant , Child, Preschool , Child , Female , Disinfection , Fomites , Ultraviolet Rays , ChinaABSTRACT
The historically dominant SARS-CoV-2 Delta variants and the currently dominant Omicron variants carry a T492I substitution within the non-structural protein 4 (NSP4). Based on a combination of in silico analyses, we predicted that the T492I mutation increases the transmissibility and adaptability of the virus. We confirmed this hypothesis by performing competition experiments in hamsters and in human airway tissue culture models. Furthermore, we show that the T492I mutation also increases the replication capacity and infectiveness of the virus, and improves its ability to evade antibody neutralization induced by previous variants. Mechanistically, the T492I mutation increases cleavage efficiency of the viral main protease NSP5 by enhancing enzyme-substrate binding, resulting in increased production of nearly all non-structural proteins processed by NSP5. Importantly, T492I mutation suppresses the viral RNA associated chemokines in monocytic macrophages, which may contribute to the attenuated pathogenicity of Omicron variants. Our results highlight the importance of the NSP4 mutation in the evolutionary dynamics of SARS-CoV-2 and identify a novel target for the development of broad-spectrum antiviral agents.
ABSTRACT
In order to investigate the clinical features of pregnant women and their neonates with coronavirus disease 2019 (COVID-19) and the evidence of vertical transmission of COVID-19, we retrieved studies included in PubMed, Medline and Chinese databases from January 1, 2000 to October 25, 2020 using relevant terms, such as 'COVID-19', 'vertical transmission' et al. in 'Title/Abstract'. Case reports and case series were included according to the inclusion and exclusion criteria. We conducted literature screening and data extraction, and performed literature bias risk assessment. Total of 13 case series and 16 case reports were collected, including a total of 564 pregnant women with COVID-19 and their 555 neonates, of which 549 neonates received nucleic acid test for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and 18 neonates was diagnosed with COVID-19. The positive rate is 3.28%. Amniotic fluid of one woman was tested positive for SARS-CoV-2. The majority of infected neonates were born under strict infection control and received isolation and artificial feeding. Up till now, there is no sufficient evidence to exclude the possibility of vertical transmission for COVID-19 based on the current available data.