Within-host dynamics of SARS-CoV-2 infection: A systematic review and meta-analysis.

Within-host model specified by viral dynamic parameters is a mainstream tool to understand SARS-CoV-2 replication cycle in infected patients. The parameter uncertainty further affects the output of the model, such as the efficacy of potential antiviral drugs. However, gathering empirical data on these parameters is challenging. Here, we aim to conduct a systematic review of viral dynamic parameters used in within-host models by calibrating the model to the viral load data measured from upper respiratory specimens. We searched the PubMed, Embase and Web of Science databases (between 1 December 2019 and 10 February 2022) for within-host modelling studies. We identified seven independent within-host models from the above nine studies, including Type I interferon, innate response, humoral immune response or cell-mediated immune response. From these models, we extracted and analyse seven widely used viral dynamic parameters including the viral load at the point of infection or symptom onset, the rate of viral particles infecting susceptible cells, the rate of infected cells releasing virus, the rate of virus particles cleared, the rate of infected cells cleared and the rate of cells in the eclipse phase can become productively infected. We identified seven independent within-host models from nine eligible studies. The viral load at symptom onset is 4.78 (95% CI:2.93, 6.62) log(copies/ml), and the viral load at the point of infection is -1.00 (95% CI:-1.94, -0.05) log(copies/ml). The rate of viral particles infecting susceptible cells and the rate of infected cells cleared have the pooled estimates as -6.96 (95% CI:-7.66, -6.25) log([copies/ml]-1 day-1 ) and 0.92 (95% CI:-0.09, 1.93) day-1 , respectively. We found that the rate of infected cells cleared was associated with the reported model in the meta-analysis by including the model type as a categorical variable (p < .01). Joint viral dynamic parameters estimates when parameterizing within-host models have been published for SARS-CoV-2. The reviewed viral dynamic parameters can be used in the same within-host model to understand SARS-CoV-2 replication cycle in infected patients and assess the impact of pharmaceutical interventions.

Reproduction numbers of SARS-CoV-2 Omicron subvariants.

HIGHLIGHT: Estimating the effective reproduction number of Omicron subvariants is crucial for evaluating the effectiveness of control measures, and adjusting control measures promptly. We conducted a systematic review to synthesize the evidence from estimates of the reproduction numbers for Omicron subvariants, and estimated their effective reproduction number.

Antiviral Drugs Screening for Swine Acute Diarrhea Syndrome Coronavirus.

Coronaviruses as possible cross-species viruses have caused several epidemics. The ongoing emergency of coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 has posed severe threats to the global economy and public health, which has generated great concerns about zoonotic viruses. Swine acute diarrhea syndrome coronavirus (SADS-CoV), an alpha-coronavirus, was responsible for mass piglet deaths, resulting in unprecedented economic losses, and no approved drugs or vaccines are currently available for SADS-CoV infection. Given its potential ability to cause cross-species infection, it is essential to develop specific antiviral drugs and vaccines against SADS-CoV. Drug screening was performed on a total of 3523 compound-containing drug libraries as a strategy of existing medications repurposing. We identified five compounds (gemcitabine, mycophenolate mofetil, mycophenolic acid, methylene blue and cepharanthine) exhibiting inhibitory effects against SADS-CoV in a dose-dependent manner. Cepharanthine and methylene blue were confirmed to block viral entry, and gemcitabine, mycophenolate mofetil, mycophenolic acid and methylene blue could inhibit viral replication after SADS-CoV entry. This is the first report on SADS-CoV drug screening, and we found five compounds from drug libraries to be potential anti-SADS-CoV drugs, supporting the development of antiviral drugs for a possible outbreak of SADS-CoV in the future.

Sub-lineages of the SARS-CoV-2 Omicron variants: Characteristics and prevention.

Since the start of the coronavirus disease 2019 (COVID-19) pandemic, new variants of severe acute respiratory syndrome coronavirus 2 (SARS­CoV­2) have emerged, accelerating the spread of the virus. Omicron was defined by the World Health Organization in November 2021 as the fifth "variant of concern" after Alpha, Beta, Gamma, and Delta. In recent months, Omicron has become the main epidemic strain. Studies have shown that Omicron carries more mutations than Alpha, Beta, Gamma, Delta, and wild-type, facilitating immune escape and accelerating its transmission. This review focuses on the Omicron variant's origin, transmission, main biological features, subvariants, mutations, immune escape, vaccination, and detection methods. We also discuss the appropriate preventive and therapeutic measures that should be taken to address the new challenges posed by the Omicron variant. This review is valuable to guide the surveillance, prevention, and development of vaccines and other therapies for Omicron variants. It is desirable to develop a more efficient vaccine against the Omicron variant and take more effective measures to constrain the spread of the epidemic and promote public health.

Surveillance and Response to Imported Malaria During the COVID-19 Epidemic - Anhui Province, China, 2019-2021.

What is already known about this topic?: China was certified malaria-free on June 30, 2021. However, imported malaria continuously threatens the effort to prevent re-establishment of malaria in China. What is added by this report?: Measures such as international travel restrictions, entry quarantine, and screening in fever clinics during the coronavirus disease 2019 (COVID-19) period were associated with a significant decrease of imported malaria cases in Anhui Province, a higher proportion of non-Plasmodium falciparum (non-P. falciparum) malaria reported infections, and a higher proportion of cases requiring medical attention at their initial visit. What are the implications for public health practices?: It is necessary to be vigilant about imported malaria during the COVID-19 epidemic, especially for non-P. falciparum infections which are more difficult to detect, and to promote research, development, and introduction of more sensitive and specific point-of-care detection methods for non-P. falciparum species.

Cepharanthine: A Promising Old Drug against SARS-CoV-2.

Recently, the inhibiting effects of a clinically approved drug Cepharanthine on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have attracted widespread attention and discussion. However, the public does not understand the relevant research progress very well. This paper aims to introduce a brief history of studies on the effects of cepharanthine against SARS-CoV-2, including "discovery of anti-SARS-CoV-2 activity of cepharanthine in vitro", "potential mechanisms of cepharanthine against SARS-CoV-2", "confirmation of cepharanthine's anti-SARS-CoV-2 activity in vivo", "potential approaches for improving the druggability of cepharanthine" and "clinical trials of cepharanthine treating SARS-CoV-2 infection". Taken together, cepharanthine is believed to be a promising old drug for coronavirus disease-19 (COVID-19) therapy.

Overview of Breastfeeding Under COVID-19 Pandemic.

During the global pandemic of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), pregnant and lactating women are at higher risk of infection. The potential of viral intrauterine transmission and vertical transmission by breastfeeding has raised wide concerns. Breastmilk is rich in nutrients that contribute to infant growth and development, and reduce the incidence rate of infant illness and death, as well as inhibit pathogens significantly, and protect infants from infection. Although it is controversial whether mothers infected with COVID-19 should continue to breastfeed, many countries and international organizations have provided recommendations and guidance for breastfeeding. This review presents the risks and benefits of breastfeeding for mothers infected with COVID-19, and the reasons for the absence of SARS-CoV-2 active virus in human milk. In addition, the antiviral mechanisms of nutrients in breastmilk, the levels of SARS-CoV-2 specific antibodies in breastmilk from COVID-19 infected mothers and vaccinated mothers are also summarized and discussed, aiming to provide some support and recommendations for both lactating mothers and infants to better deal with the COVID-19 pandemic.

Reproduction Number of the Omicron Variant Triples That of the Delta Variant.

COVID-19 remains a persistent threat, especially with the predominant Omicron variant emerging in early 2022, presenting with high transmissibility, immune escape, and waning. There is a need to rapidly ramp up global vaccine coverage while enhancing public health and social measures. Timely and reliable estimation of the reproduction number throughout a pandemic is critical for assessing the impact of mitigation efforts and the potential need to adjust for control measures. We conducted a systematic review on the reproduction numbers of the Omicron variant and gave the pooled estimates. We identified six studies by searching PubMed, Embase, Web of Science, and Google Scholar for articles published between 1 January 2020 and 6 March 2022. We estimate that the effective reproduction number ranges from 2.43 to 5.11, with a pooled estimate of 4.20 (95% CI: 2.05, 6.35). The Omicron variant has an effective reproduction number which is triple (2.71 (95% CI: 1.86, 3.56)) that of the Delta variant.

Structural features of an acidic polysaccharide with the potential of promoting osteoblast differentiation from Lycium ruthenicum Murr.

The enhanced osteoblast differentiation is beneficial to the prevention of osteoporosis. In this study, a homogeneous polysaccharide (LRP-S2A) with the potential of promoting osteoblast differentiation was obtained from the fruits of Lycium ruthenicum, a traditional herb for treatment of postmenopausal metabolic disorders. Structural identification indicated that LRP-S2A, with a relative molecular weight of 2.65 × 106 Da and an uronic acid content of 41.8%, contained Rha, Ara, Gal, Glc and GlcA in a molar ratio of 1.00 : 2.07 : 0.57 : 2.59 : 4.33 and was composed of a backbone consisting of 6-O-Me-α-(1→4)-D-GlcpA, 2-O-acetyl-α-(1→4)-D-Glcp, α-(1→2,4)-L-Rhap, ß-(1→3)-D-Galp andα-(1→3,5)-L-Araf, and some branches consisting of 6-O-Me-α-(1→4)-D-GlcpA and terminal α-L-Araf. These results suggested that LRP-S2A with the potential of promoting osteoblast differentiation was a new acidic polysaccharide.

Tocilizumab among patients with COVID-19 in the intensive care unit: a multicentre observational study.

BACKGROUND: Tocilizumab, a monoclonal antibody directed against the interleukin-6 receptor, has been proposed to mitigate the cytokine storm syndrome associated with severe COVID-19. We aimed to investigate the association between tocilizumab exposure and hospital-related mortality among patients requiring intensive care unit (ICU) support for COVID-19. METHODS: We did a retrospective observational cohort study at 13 hospitals within the Hackensack Meridian Health network (NJ, USA). We included patients (aged ≥18 years) with laboratory-confirmed COVID-19 who needed support in the ICU. We obtained data from a prospective observational database and compared outcomes in patients who received tocilizumab with those who did not. We applied a multivariable Cox model with propensity score matching to reduce confounding effects. The primary endpoint was hospital-related mortality. The prospective observational database is registered on ClinicalTrials.gov, NCT04347993. FINDINGS: Between March 1 and April 22, 2020, 764 patients with COVID-19 required support in the ICU, of whom 210 (27%) received tocilizumab. Factors associated with receiving tocilizumab were patients' age, gender, renal function, and treatment location. 630 patients were included in the propensity score-matched population, of whom 210 received tocilizumab and 420 did not receive tocilizumab. 358 (57%) of 630 patients died, 102 (49%) who received tocilizumab and 256 (61%) who did not receive tocilizumab. Overall median survival from time of admission was not reached (95% CI 23 days-not reached) among patients receiving tocilizumab and was 19 days (16-26) for those who did not receive tocilizumab (hazard ratio [HR] 0·71, 95% CI 0·56-0·89; p=0·0027). In the primary multivariable Cox regression analysis with propensity matching, an association was noted between receiving tocilizumab and decreased hospital-related mortality (HR 0·64, 95% CI 0·47-0·87; p=0·0040). Similar associations with tocilizumab were noted among subgroups requiring mechanical ventilatory support and with baseline C-reactive protein of 15 mg/dL or higher. INTERPRETATION: In this observational study, patients with COVID-19 requiring ICU support who received tocilizumab had reduced mortality. Results of ongoing randomised controlled trials are awaited. FUNDING: None.