Is the SARS CoV-2 Omicron Variant Deadlier and More Transmissible Than Delta Variant?

How Nanoparticle Aerosols Transport through Multi-Stenosis Sections of Upper Airways: A CFD-DPM Modelling

Airway stenosis is a global respiratory health problem that is caused by airway injury, endotracheal intubation, malignant tumor, lung aging, or autoimmune diseases. A precise understanding of the airflow dynamics and pharmaceutical aerosol transport through the multi-stenosis airways is vital for targeted drug delivery, and is missing from the literature. The object of this study primarily relates to behaviors and nanoparticle transport through the multi-stenosis sections of the trachea and upper airways. The combination of a CT-based mouth–throat model and Weibel’s model was adopted in the ANSYS FLUENT solver for the numerical simulation of the Euler–Lagrange (E-L) method. Comprehensive grid refinement and validation were performed. The results from this study indicated that, for all flow rates, a higher velocity was usually found in the stenosis section. The maximum velocity was found in the stenosis section having a 75% reduction, followed by the stenosis section having a 50% reduction. Increasing flow rate resulted in higher wall shear stress, especially in stenosis sections. The highest pressure was found in the mouth–throat section for all flow rates. The lowest pressure was usually found in stenosis sections, especially in the third generation. Particle escape rate was dependent on flow rate and inversely dependent on particle size. The overall deposition efficiency was observed to be significantly higher in the mouth–throat and stenosis sections compared to other areas. However, this was proven to be only the case for a particle size of 1 nm. Moreover, smaller nanoparticles were usually trapped in the mouth–throat section, whereas larger nanoparticle sizes escaped through the lower airways from the left side of the lung; this accounted for approximately 50% of the total injected particles, and 36% escaped from the right side. The findings of this study can improve the comprehensive understanding of airflow patterns and nanoparticle deposition. This would be beneficial in work with polydisperse particle deposition for treatment of comprehensive stenosis with specific drugs under various disease conditions.

Assessment of SARS-CoV-2 Infected Patients and Their Clinical Outcomes During the Third Wave in India: A Single-Center Observational Study

Background

The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) that emerged from the Chinese mainland has spread throughout the world affecting the normal lives of the people. Both developed and developing nations have been equally affected and coronavirus disease-19 (COVID-19) resulted in the death of millions of people worldwide. The virus is undergoing mutations and is evolving into variants that are responsible for wave after wave. This study was carried out to assess the clinical outcomes of people infected with the novel virus during the third wave of the COVID-19 pandemic in India.

Methods

The study was carried out between November 2021 and January 2022 and included 100 consecutive patients attending the hospital attached to the BLDE (Deemed to be University) Shri B.M. Patil Medical College, Bijapur, Karnataka, South India. All patients included in the study returned a positive report in a real-time polymerase chain reaction (RT-PCR). The patient details collected included age, sex, cycle threshold (Ct) values for envelope (E)/nucleocapsid (N), and Orf1b (open reading frame 1b) genes, hospitalization status, vaccine status, C-reactive protein (CRP), D-dimer, interleukin-6 (IL-6), and final clinical outcome. The data were entered into Microsoft Office Excel sheets, and statistical inferences were drawn using SPSS 24 (IBM Corp., Armonk, NY).

Results

Of the 100 patients included in the study, only 14 (14%) patients were vaccinated. The patient's mean age was 34.22±17.50. Among the vaccinated patients, the majority had taken COVISHIELD™ (85.71%) compared to COVAXIN^® (14.29%). Only 14% of patients were symptomatic, and the mean Ct values among all the patients were 29.92±3.74 (E gene/N gene) and 27.6±4.78 (Orf1B gene). Eight (8%) patients were hospitalized, and all the patients recovered from the infection. Among the hospitalized patients, six (75%) were vaccinated. The mean age of the hospitalized patients was 43.8±14.25 years. The mean CRP, D-dimer, and IL-6 concentrations among the hospitalized patients were noted to be 22.375±16.58 mg/L, 654.325±577.24 ng/mL, and 5.075±2.15 ng/mL, respectively.

Conclusion

The study results demonstrate that despite unvaccinated status, most patients in the third wave had only suffered from asymptomatic infection. Moreover, people who developed a clinical infection and those who required hospitalization had an uneventful recovery irrespective of their vaccination status.

Epidemiological Trends of Coronavirus Disease 2019 in Sierra Leone From March 2020 to October 2021

Coronavirus disease 2019 (COVID-19), a serious public health challenge the world over, has led to significant health concerns in Sierra Leone. In the present study, epidemic indices, such as the number of cases, positivity rate, reproduction rate (R0), case fatality rate (CFR), age, and sex, were used to characterize the epidemiological trends of COVID-19. As of October 31, 2021, a total of 6,398 cases and 121 related deaths had been confirmed. The total number of COVID-19 reverse transcription polymerase chain reaction (RT-PCR) tests conducted to October 31, 2021, was 249,534, and the average positivity rate was 2.56%. Three waves of COVID-19 were recorded, occurring during weeks 15–46 in 2020 (2,369 cases), week 47 in 2020 to week 16 in 2021 (1,665 cases), and weeks 17–43 in 2021 (2,364 cases), respectively. Remarkably, there was no increase in the numbers of confirmed COVID-19 cases despite rising test numbers throughout the three waves. Moreover, three high R0 values were observed before each wave. The number of positive cases significantly correlated with positive numbers of international arrivals (P < 0.01), deaths (P < 0.01), and the positivity rate of tested samples (P < 0.01). Moreover, all of the deaths occurred during the peak of the three waves. Our results indicate that there was a low level of COVID-19 epidemic in Sierra Leone and that COVID-19's introduction led to local transmission. It is vital to fight against the spread of SARS-CoV-2 from the source of origin by strengthening testing and management of people entering the country. Our findings will provide important clues for expanding sample screening and will contribute to the reasonable allocation of medical resources.

How Effective Is a Traffic Control Policy in Blocking the Spread of COVID-19? A Case Study of Changsha, China

(1) Background: COVID-19 is still affecting people’s daily lives. In the past two years of epidemic control, a traffic control policy has been an important way to block the spread of the epidemic. (2) Objectives: To delve into the blocking effects of different traffic control policies on COVID-19 transmission. (3) Methods: Based on the classical SIR model, this paper designs and improves the coefficient of the infectious rate, and it builds a quantitative SEIR model that considers the infectivity of the exposed for traffic control policies. Taking Changsha, a typical city of epidemic prevention and control, as a study case, this paper simulates the epidemic trends under three traffic control policies adopted in Changsha: home quarantine, road traffic control, and public transport suspension. Meanwhile, to explore the time sensitivity of all traffic control policies, this paper sets four distinct scenarios where the traffic control policies were implemented at the first medical case, delayed by 3, 5, and 7 days, respectively. (4) Results: The implementation of the traffic control policies has decreased the peak value of the population of the infective in Changsha by 66.03%, and it has delayed the peak period by 58 days; with the home-quarantine policy, the road traffic control policy, and the public transport suspension policy decreasing the peak value of the population of the infective by 56.81%, 39.72%, and 45.31% and delaying the peak period by 31, 18, and 21 days, respectively; in the four scenarios where the traffic control policies had been implemented at the first medical case, delayed by 3, 5, and 7 days, respectively, the variations of both the peak value and the peak period timespan of confirmed cases under the home-quarantine policy would have been greater than under the road traffic control and the public transport suspension policies. (5) Conclusions: The implementation of traffic control policies is significantly effective in blocking the epidemic across the city of Changsha. The home-quarantine policy has the highest time sensitivity: the earlier this policy is implemented, the more significant its blocking effect on the spread of the epidemic.

Cleavage of the selective autophagy receptor SQSTM1/p62 by the SARS-CoV-2 main protease NSP5 prevents the autophagic degradation of viral membrane proteins

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused the coronavirus disease 2019 (COVID-19) global pandemic. Omicron, a new variant of SARS-CoV-2, has the characteristics of strong transmission and pathogenicity, short incubation period, and rapid onset progression, and has spread rapidly around the world. The high replication rate and intracellular accumulation of SARS-CoV-2 are remarkable, but the underlying molecular mechanisms remain unclear. Autophagy acts as a conservative cellular defence mechanism against invading pathogens. Here, we provide evidence that the main protease of SARS-CoV-2, NSP5, effectively cleaves the selective autophagy receptor p62. NSP5 targets p62 for cleavage at glutamic acid 354 and thus abolishes the capacity of p62 to mediate selective autophagy. It was further shown that p62 specifically interacted with ubiquitinated SARS-CoV-2 M, the viral membrane protein, to promote its autophagic degradation. In the presence of NSP5, p62-mediated autophagic degradation of the M protein was inhibited. The cleaved products of p62 also cannot facilitate the degradation of the M protein. Collectively, our findings reveal that p62 is a novel host target of SARS-CoV-2 NSP5 and suggest that selective autophagy targets viruses and potential strategies by which the virus evades autophagic clearance. Our results may provide new ideas for the development of anti-COVID-19 drugs based on autophagy and NSP5.

Using unstable data from mobile phone applications to examine recent trajectories of retail centre recovery

The COVID-19 pandemic has changed the ways in which we shop, with significant impacts on retail and consumption spaces. Yet, empirical evidence of these impacts, specifically at the national level, or focusing on latter periods of the pandemic remain notably absent. Using a large spatio-temporal mobility dataset, which exhibits significant temporal instability, we explore the recovery of retail centres from summer 2021 to 2022, considering in particular how these responses are determined by the functional and structural characteristics of retail centres and their regional geography. Our findings provide important empirical evidence of the multidimensionality of retail centre recovery, highlighting in particular the importance of composition, e-resilience and catchment deprivation in determining such trajectories, and identifying key retail centre functions and regions that appear to be recovering faster than others. In addition, we present a use case for mobility data that exhibits temporal stability, highlighting the benefits of viewing mobility data as a series of snapshots rather than a complete time series. It is our view that such data, when controlling for temporal stability, can provide a useful way to monitor the economic performance of retail centres over time, providing evidence that can inform policy decisions, and support interventions to both acute and longer-term issues in the retail sector.