ABSTRACT
Objective: Understanding the minimum infective dose is significant for risk assessment in the performance of suitable infection control strategies in healthcare centers. However, the literature lacks strong evidence regarding this value for severe acute respiratory syndrome coronavirus 2. Therefore, the aim of this study was to investigate the minimum infectious dose of coronavirus disease 2019. Methods: We searched the databases of PubMed, Scopus, Web of Science, and Cochrane and retrieved all the relevant literature by 25 July 2021. The records were downloaded into the EndNote software and underwent title/abstract and full-text screenings. A summary of included studies was organized into tables for further analysis, interpretation, and drafting of the results. Results: Nineteen studies including the laboratory data on human and animal hosts were selected based on the eligibility criteria. All the literature reported on the infective dose, particularly in humans. The main methods for measurement of infection were through tissue culture infectious dose (TCID50) and counting plaque-forming units. The range of minimum infective was 1.26-7 × 106.25 PFU. Conclusion: In this study, we have presented a range of minimum infective doses in humans and various animal species. Such numbers can possibly vary between the individuals based on numerous demographic, immunologic, or other factors.
ABSTRACT
Introduction: Airborne transmission is the most â¯crucial mode of COVID-19 transmission. Therefore, disinfecting the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) aerosols float can have important implications in limiting COVID-19 transmission. Herein, we aimed to review the studies that utilized various disinfectants to decontaminate and inactivate the SARS-CoV-2 aerosols. Methods: This study was a review that studied related articles published between December 1, 2019 and August 23, 2022. We searched the online databases of PubMed, Scopus, Web of Science, Cochrane, on August 23, 2021. The studies were downloaded into the EndNote software, duplicates were removed, and then the studies were screened based on the inclusion/exclusion criteria. The screening process involved two steps; first, the studies were screened based on their title and abstract and then their full texts. The included studies were used for the qualitative analysis. Results: From 664 retrieved records, only 31 met the inclusion criteria and were included in the final qualitative analysis. Various materials like Ozone, H2O2, alcohol, and TiO2 and methods like heating and using Ultraviolet were described in these studies to disinfect places contaminated by COVID-19. It appeared that the efficacy of these disinfectants varies considerably depending on the situation, time, and ultimately their mode of application. Conclusion: Following reliable protocols in combination with the proper selection of disinfectant agents for each purpose would serve to achieve desired elimination of the SARS-CoV-2 transmission.
ABSTRACT
Introduction: C-reactive protein (CRP) and cytokines levels could alter in patients with coronavirus disease (COVID-19) due to the inflammatory response caused by the virus. This analysis aimed to assess the relationship between the CRP levels and the levels of various cytokines in COVID-19 patients. Materials and Methods: We searched the databases of PubMed, Cochrane, and Web of Science for relevant articles on May 29th, 2021. Applying the inclusion/exclusion criteria, the retrieved records underwent two-phase screenings; first, a title/abstract screening process, and then, a full-text screening to find the eligible studies. Data for study variables were extracted, including the CRP levels and the levels of all reported cytokines. A strong and significant relationship between Interleukins and CRP was defined as: p ≤ 0.05, 0.7 ≤ r ≤ 1. Results: In this study, 103 studies were included for systematic review and correlation analysis. The aggregate mean and SD of study variables were calculated and reported. The correlation between Interleukins and CRP was measured using correlation coefficient (r). It appeared that interleukin (IL)-10 has a moderate and significant relationship with CRP (p ≤ 0.05, r = 0.472). IL-10 predicted almost 10% of CRP changes. Conclusion: This correlation analysis suggests IL-10 is moderately correlated with CRP levels in patients with COVID-19 infection. A better understanding of the pro-inflammatory markers could contribute to the implementation of therapeutic and preventive approaches. More prospective studies are suggested to explore the relationship between CRP and cytokines as potential markers for the early identification of COVID-19 progression and severity.
ABSTRACT
Objective: Understanding the minimum infective dose is significant for risk assessment in the performance of suitable infection control strategies in healthcare centers. However, the literature lacks strong evidence regarding this value for severe acute respiratory syndrome coronavirus 2. Therefore, the aim of this study was to investigate the minimum infectious dose of coronavirus disease 2019. Methods: We searched the databases of PubMed, Scopus, Web of Science, and Cochrane and retrieved all the relevant literature by 25 July 2021. The records were downloaded into the EndNote software and underwent title/ and full-text screenings. A summary of included studies was organized into tables for further analysis, interpretation, and drafting of the results. Results: Nineteen studies including the laboratory data on human and animal hosts were selected based on the eligibility criteria. All the literature reported on the infective dose, particularly in humans. The main methods for measurement of infection were through tissue culture infectious dose (TCID50) and counting plaque-forming units. The range of minimum infective was 1.26–7 × 106.25 PFU. Conclusion: In this study, we have presented a range of minimum infective doses in humans and various animal species. Such numbers can possibly vary between the individuals based on numerous demographic, immunologic, or other factors.
ABSTRACT
INTRODUCTION: Patients with COVID-19 may present different viral loads levels. However, the relationship between viral load and disease severity in COVID-19 is still unknown. Therefore, this study aimed to systematically review the association between SARS-CoV-2 viral load and COVID-19 severity. METHODS: The relevant studies using the keywords of "COVID-19" and "viral load" were searched in the databases of PubMed, Scopus, Google Scholar, and Web of Science. A two-step title/abstract screening process was carried out and the eligible studies were included in the study. RESULTS: Thirty-four studies were included from the initial 1015 records. The vast majority of studies have utilized real-time reverse transcription-polymerase chain reaction of the nasopharyngeal/respiratory swabs to report viral load. Viral loads were commonly reported either as cycle threshold (Ct ) or log10 RNA copies/ml. CONCLUSION: The results were inconclusive about the relationship between COVID-19 severity and viral load, as a similar number of studies either approved or opposed this hypothesis. However, the studies denote the direct relationship between older age and higher SARS-CoV-2 viral load, which is a known risk factor for COVID-19 mortality. The higher viral load in older patients may serve as a mechanism for any possible relationships between COVID-19 viral load and disease severity. There was a positive correlation between SARS-CoV-2 viral load and its transmissibility. Nonetheless, further studies are recommended to precisely characterize this matter.