Comparison of Omicron and Delta Variants of SARS-CoV-2: A Systematic Review of Current Evidence

INTRODUCTION

Severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) caused the outbreak of coronavirus disease 2019 (COVID-19) in late 2019 in Wuhan, China. In early 2020, the disease spread rapidly around the world. Since the pandemic, SARS-CoV-2 has evolved dramatically into a wide variety of variants endowed with devastating properties. As of March 6, 2022, five SARS-CoV-2 variants of concern, including Alpha, Beta, Gamma, Delta, and Omicron strains have been identified. Due to the crucial importance of understanding the differences between the Omicron and Delta variants, this systematic review was conducted.

METHODS

This systematic review investigated new variants of Omicron SARS-CoV-2 based on cur-rent studies. Online databases were searched for English articles as of January 03, 2023. Selection of publications was a two-step process of title/abstract and full-text assessment against eligibility crite-ria. The relevant data from the included articles were systematically collected and organized in a designed table for analysis. To ensure the quality of the review, the PRISMA checklist and Newcas-tle-Ottawa Scale (NOS) of quality assessment were utilized.

RESULTS

The data extracted from 58 articles were analyzed, including 10003 pieces of evidence. Lower risk of hospitalization, ICU admission, and mortality after vaccination were reported in the Omicron variant compared to the Delta variant. Additionally, the Delta variant led to more severe clinical symptoms in comparison to the Omicron variant.

CONCLUSION

The Omicron variant of SARS-CoV-2 results in less severe disease outcomes as com-pared to Delta. Nevertheless, it remains crucial to maintain ongoing monitoring, implement contain-ment measures, and adapt vaccination protocols to effectively address the evolving variants.

The impact of COVID-19 pandemic on the levels of physical activity: A systematic review

INTRODUCTION

Earlier studies demonstrated a decreased level of physical activity (PA) during the COVID-19 pandemic. Therefore, we aimed to systematically review the relevant studies among various age groups and explore the impact on physical and mental health.

METHODS

We searched and retrieved all relevant articles using the keywords on the online databases of PubMed, Embase, and Cochrane from the start of the pandemic until May 3rd, 2021. A two-phase screening process of identified records was carried out to shortlist the most relevant studies. First, the studies were evaluated based on their title/abstract, and then the full-text of included studies was thoroughly read. The eligible studies based on the eligibility criteria were included in this review.

RESULTS

A total of 57 studies were included based on the eligibility criteria. Lockdowns and infection with SARS-CoV-2 have led to a decreased level of PA in the general population compared to the pre-pandemic era. Men had significantly less PA compared to women in some studies, probably due to higher pre-pandemic PA. The level of PA among those with chronic diseases also significantly diminished, putting them at a higher risk of cardiovascular incidents. Sedentary lifestyles have dominated people's life, including adolescents and university students. The increased levels of mental health issues, such as depression, anxiety, and occupational stress, have been suggested to contribute to the decreased PA. On the other hand, the decreased PA appeared to lead to more mental health issues. Fortunately, the decreasing trend of PA seemed to taper towards the end of the quarantines.

CONCLUSION

Overall, the COVID-19 pandemic and subsequent quarantines reduced PA among all age groups and both sexes and had detrimental effects on people's physical and mental health. We suggest countries implement strategies to alleviate restrictions and encourage people to exercise in safe environments and prepare healthy routines for themselves.

Evaluating the effects of air disinfectants in decontamination of COVID-19 aerosols

Introduction

Airborne transmission is the most  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.

Soluble ACE2 as a Risk or Prognostic Factor in COVID-19 Patients: A Cross-sectional Study

Background: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel severe acute respiratory syndrome coronavirus. The first known receptor for this virus in the human body is angiotensin-converting enzyme 2 (ACE2), the same receptor for the SARS virus. Methods: A total of 38 hospitalized adult (18 years) patients with laboratory or clinically confirmed coronavirus disease 2019 (COVID-19) were identified in the infectious disease ward of Tehran Imam Khomeini hospital complex in this single-center cross-sectional study. A blood sample was taken at the time of hospitalization and a second one was taken 48 hours later. Blood samples are kept frozen at -80 degrees Celsius. After the complete collection of samples, the ACE2 level of the samples was measured using a serum sACE2 detection ELISA kit. The data were analyzed using SPSS v26. P value of 0.05 was considered statistically significant. An analysis of covariance was performed to examine the mean differences in day 7 serum ACE2 concentration among the 2 groups after adjusting for the baseline serum ACE2 concentration. The 1-way multivariate analysis of variance was used to determine whether there were any differences between independent groups (mechanical ventilation yes/no) on serum ACE2 levels at 3 different times. Results: The mean age of patients was 64.13 ± 16.49 years, 21 patients (55.3%) were men, 16 patients (42%) were polymerase chain reaction test positive, and 15 patients (39.5%) died. A total of 35 individuals (92.1%) had chest computed tomography images that indicated lung involvement. A comparison of the 2 groups of patients who died and were discharged revealed that serum ACE2 at the first (p=0.033) and third (7th day) measurements were statistically different (p=0.026). Patients had a mean of serum ACE2. The results indicated that the day 7 serum ACE2 concentration did significantly differ between the 2 groups after controlling for the baseline serum ACE2 concentration (p=0.023). The model explained about 73.61% of the variance in the 7-day serum ACE2 concentration. Specifically, after adjusting for the baseline concentration, survived patients had the lowest level of serum ACE2 concentration (1 ± 0.65) on the 7th day compared with the deceased patient group (2.83 ± 1.12). Conclusion: Soluble ACE2 in the serum of COVID-19 patients who died, later on, was significantly higher than the discharged patients when the samples were taken seven days after admission. It is suggested that serum soluble ACE2 level could be used as a prognostic factor for COVID-19 patients' outcomes and also their need for mechanical ventilation.

Public acceptability of COVID-19 vaccines and its predictors in Middle ‎Eastern/North African (MENA) countries: a systematic review‎

Introduction

COVID-19 vaccines emerged as a worldwide hope to contain the pandemic. However, many people ‎are still hesitant to receive these vaccines. We aimed to systematically review the public knowledge, perception, and acceptability of COVID-19 vaccines in the Middle East and North Africa (MENA) countries and the predictors of vaccine acceptability in this region.

Methods

We systematically searched databases of PubMed, Scopus, Web of Science, and Cochrane and retrieved ‎all relevant studies by 5 August 2021.

Results

There was a considerable variation in the COVID-19 vaccine acceptance ‎rates, from 12% in a study from Israel to 83.3% in Kuwait, although two other studies from Israel mentioned 75% ‎and 82.2% acceptability rates. Concerns about the side effects and safety of the vaccine were the main reasons for ‎the lack of acceptability of taking the vaccine, which was reported in 19 studies. ‎

Conclusion

Several factors, such as age, gender, education level, and comorbidities, ‎are worthy of attention as they could expand vaccine coverage in the target population.‎

Mucormycosis infection in patients with COVID ‐19: A systematic review

Introduction

Several reports previously described mucormycosis co‐infection in patients with COVID‐19. As mucormycosis and COVID‐19 co‐infection might adversely affect patients' outcomes, we aimed to systematically review the related evidence and the subsequent outcomes.

Methods

We conducted a systematic review of relevant articles searching the keywords in the online databases of PubMed, Scopus, Embase, Cochrane, and Web of Science. All the records from the start of the pandemic until June 12th, 2021 underwent title/abstract and then full‐text screening process, and the eligible studies were included. We did not include any language or time restrictions for the included studies.

Results

We found 31 eligible studies reporting 144 total cases of COVID‐19 and mucormycosis co‐infection. The nose, cranial sinuses, and orbital cavity were the most commonly involved organs, although the cerebrum, lungs, and heart were also involved in the studies. Pre‐existing diabetes mellitus (DM), as well as corticosteroid use, were the most commonly identified risk factors, but other underlying conditions and immunomodulatory drug use were also present in several cases. Aspergillus was the most commonly reported micro‐organism that caused further co‐infections in patients with concurrent COVID‐19 and mucormycosis. As most of the studies were case reports, no reliable estimate of the mortality rate could be made, but overall, 33.6% of the studied cases died.

Conclusion

Early diagnosis of mucormycosis co‐infection in COVID‐19 patients and selecting the right treatment plan could be a challenge for physicians. Patients with underlying co‐morbidities, immunocompromised patients, and those receiving corticosteroids are at higher risk of developing mucormycosis co‐infection and it is crucial to have an eye examination for early signs and symptoms suggesting a fungal infection in these patients.

Effect of Chloroquine on Hyoscine-Induced Memory Impairment in Mice: Possible Involvement of Opioids and Nitric Oxide

Supporting evidence suggests the possible neuroprotective potential of chloroquine, an anti-malaria medication. Moreover, reports indicate that endogenous opioids and nitric oxide (NO) play role of a mediator by chloroquine’s effects. In the present study, the effects of chloroquine on hyoscine-induced memory impairment were assessed. Furthermore, the possible involvements of opioids and NO were evaluated. Chloroquine was administered intraperitoneally (i.p.) at doses of 0.1, 0.5, 1, 3, 10, and 20 mg/kg to hyoscine-treated (1 mg/kg, i.p.) mice, and the spatial and fear memories were evaluated using Y-maze and passive-avoidance tasks, respectively. Also, to provide further evidence about chloroquine’s mechanism of action, the opioid receptors and the NO production were blocked using two nonselective antagonist’s naltrexone and L-NAME, respectively. Chloroquine at doses of 0.5, 10, and 20 mg/kg furtherly damaged the impaired memory of hyoscine-treated mice and at doses of 10 and 20 mg/kg impaired the memory of saline-treated mice in the passive avoidance task. Additionally, chloroquine at doses of 0.5 and 1 mg/kg improved the spatial memory in hyoscine-treated mice in the Y-maze test. In addition, naltrexone (3 mg/kg) reversed the neuroprotective effect of chloroquine (1 mg/kg) in hyoscine-treated mice in the Y-maze task. It could be concluded that chloroquine at low doses may improve cognitive performance by involving the opioid receptors; as a result, blocking the opioid receptors may reverse chloroquine’s neuroprotective effect. Notably, chloroquine at high doses did not improve the memory, and in combination with hyoscine, it caused even more damage to long-term memory.

Impact of COVID ‐19 pandemic on routine vaccination coverage of children and adolescents: A systematic review

Background and Aims

Scientists and healthcare workers have expressed their concerns on the impacts of the COVID‐19 pandemic on vaccination coverage in children and adolescents. Therefore, we aimed to systematically review the studies addressing this issue worldwide.

Methods

We conducted a systematic search of relevant studies using the keywords on databases of PubMed, Web of Science, and Cochrane on May 22, 2021. The identified records were imported into EndNote software and underwent a two‐phase screening process consisting of title/abstract and full‐text screenings against inclusion criteria. The data of the included studies were summarized into a table and the findings were analyzed in a systematic approach.

Results

From 26 eligible studies, 21 studies demonstrated decreased vaccination rates in the children during the COVID‐19 pandemic, while three studies found increased or no significant changes only in influenza vaccination. The two remaining studies from Brazil and Sweden also showed no significant changes in vaccination rates in the children during the pandemic.

Conclusion

Most of the reports worldwide reported a decline or delay in vaccination at the time of the COVID‐19 pandemic. A sustained catch‐up program seems to be necessary, especially in low‐income countries, to avoid any vaccine dose missing. Facilitating the vaccination process is recommended, such as decreasing the waiting time for vaccination at the health center, addressing the fear and concerns related to COVID infection for parents, and enhancing vaccine availability, and promoting access in remote areas. Countries should ensure proper vaccination to prevent future pandemics related to vaccine‐preventable diseases.

Early versus Delayed Intubation and Technique in COVID-19: A Review Article

Background: The novel coronavirus 2019 is the cause of the 2020 pandemic that was announced by the world health organization in March 2020. The coronavirus attacks the respiratory system and causes mild to severe hypoxemia. Therefore, a fraction of COVID-19 patients may need intubation and mechanical ventilation. Methods: We conducted a narrative review by searching for articles that mentioned the time of intubation for COVID-19 patients and intubation techniques in PubMed, Google Scholar, Scopus, the Web of scenic, the Cochrane library, and Embase, as well as manual searching. All the selected reviews and studies were limited to humans and the English language. Results: The first data from China shows that 5% of patients require intubation and mechanical ventilation (MV), and there has been considerable debate about the timing of intubation for patients with acute respiratory failure and the technique of intubation. At first, the specialists recommended early intubation. Although we are more familiar with the pathophysiology of coronavirus, the drawbacks and the benefits of early intubation are still controversial. In addition, the intubation process itself is an aerosol-generating procedure and carries a high risk for patients and health care providers. In this review, we aim to review the previous studies and guidelines recommendations related to the time of intubation and intubation technique for COVID-19 patients. Conclusion: Previous research has suggested that early tracheal intubation should be prioritized in severe COVID-19 patients, whereas other studies advocate late intubation due to poor intubation outcomes and weaning difficulties. However, intubation timing should be based on personalized medicine and case-by-case decision making to ensure the best care and benefit of patients. And relying only on theoretical justification may not have good consequences.

Opioidergic and nitrergic systems mediate the anticonvulsant effect of mefloquine and chloroquine on seizures induced by pentylenetetrazol and maximal electroshock in mice

This study was designed to investigate the involvement of opioidergic/nitrergic systems in the anticonvulsant effect of mefloquine, compared with chloroquine, in mice. Seizures were induced by pentylenetetrazol and maximal electroshock. Mice were randomly subjected to receive mefloquine or chloroquine thirty minutes in advance. The role of opioidergic/nitrergic systems was shown by co‑administration of pharmacological intervention and nitrite levels measurement in mice hippocampi. Results indicated that mefloquine (40 mg/kg) and chloroquine (5 mg/kg) significantly decreased the occurrence of tonic hindlimb extension. Also, mefloquine 120 mg/kg and chloroquine 5 mg/kg significantly increased seizure latency and decreased mortality rate. Mefloquine decreased seizure frequency too. Besides, mefloquine (20 mg/kg) and chloroquine (5, 10 mg/kg) significantly increased seizure threshold. Interestingly, L‑NAME, 7‑NI and naltrexone pre‑treatment reversed the anticonvulsant effects of both mefloquine (20 mg/kg) and chloroquine (5 mg/kg). Moreover, co‑administration of minimal‑effective doses of morphine with mefloquine/chloroquine (both 1 mg/kg) potentiated anticonvulsant effects, which was reversed by naltrexone and endorsed the involvement of opioid receptors. Also, nitrite levels in mice hippocampi remarkably increased after treatment with both mefloquine (20 mg/kg) and chloroquine (5 mg/kg). To conclude, mefloquine could protect the central nervous system against seizures in PTZ/MES‑induced models through opioidergic/nitrergic pathways, with similarity to chloroquine effects.

Microfluidic synthesis of retinoic acid-loaded nanoparticles for neural differentiation of trabecular meshwork mesenchymal stem cell

OBJECTIVES

This study aimed to fabricate the PCL-nanoparticles (NPs) loaded retinoic acid (RA) using the microfluidic system for successful cellular uptake and induction of neuronal differentiation of trabecular meshwork mesenchymal stem cells (TMMSCs).

METHODS

A microfluidic system used to synthesize RA-loaded NPs, DLS, FTIR, TEM, and UV-spectroscopy was recruited to characterize and study the release of RA. Also, the toxicity, cellular uptake, and neuronal differential of TMMSCs have been assessed.

RESULTS

According to the obtained results, the spherical NPs (117.6±0.35 nm, ‒19.4±5.3) and RA-loaded NPs (121.6±0.75 nm, ‒23.6±1.3) were synthesized successfully by microfluidic system. 7.8±2.04 % of RA was loaded in NPs, and 25 % was released in the first four hours. Thus, the NPs have been successfully internalized into the stem cells, leading to a significant increase in neural genes and protein (β Tubulin III and Map-2) expression.

CONCLUSION

Our study's harvested results have represented valid data for practical use of microfluidic systems in the term of NPs loaded RA synthesis and its successful function to cellular internalization and euronal differentiation of TMMSCs (Tab. 2, Fig. 10, Ref. 46).

A prospective, observational study of the performance of MEWS, NEWS, SIRS and qSOFA for early risk stratification for adverse outcomes in patients with suspected infections at the emergency department

BACKGROUND

Many patients with suspected infection are presented to the emergency Department. Several scoring systems have been proposed to identify patients at high risk of adverse outcomes.

METHODS

We compared generic early warning scores (MEWS and NEWS) to the (SIRS) criteria and quick Sequential Organ Failure Assessement (qSOFA), for early risk stratification in 1400 patients with suspected infection in the ED. The primary study end point was 30-day mortality.

RESULTS

The AUROC of the NEWS score for predicting 30-day mortality was 0.740 (95% Confidence Interval 0.682- 0.798), higher than qSOFA (AUROC of 0.689, 95% CI 0.615- 0.763), MEWS (AUROC 0.643 (95% CI 0.583-0.702) and SIRS (AUROC 0.586, 95%CI 0.521 - 0.651). The sensitivity was also highest for NEWS⋝ 5 (sensitivity 75,8% specificity of 67,4%).

CONCLUSION

Among patients presenting to the ED with suspected infection, early risk stratification with NEWS (cut-off of ⋝5) is more sensitive for prediction of mortality than qSOFA, MEWS or SIRS, with adequate specificity.

Brain lesions in a patient with rectal cancer: mind your step

Cerebral toxoplasmosis is a potentially fatal infection most commonly seen in immunocompromised patients. We present a patient on long-term immunosuppressive therapy after kidney transplantation and a recent history of oligometastatic rectal cancer, with cerebral lesions as a result of toxoplasmosis. Heightened awareness of the occurrence of opportunistic infections in patients with cancer who are taking immunosuppressive drugs is needed among clinicians.

Comparison of aglycon and glycosidic saponin extracts of Cyclamen coum tuber against Candida spp

BACKGROUND AND PURPOSE

Candidiasis, an important fungal infection, is considered the fourth most common nosocomial blood stream infection. Nowadays, because of increased fungal resistance to antibiotics, the use of herbal medicine has gained particular attention. Cyclamen species are medicinal plants containing triterpenoid saponins, which are shown to have antimicrobial properties.

MATERIALS AND METHODS

Three species of Candida including C.albicans, 10231 C.tropicalis 0750 ,and C.krusei and nine clinical samples were cultured on Sabouraud dextrose agar. Active substances of the tubers were extracted by fractionation method. Susceptibility of Candida to Cyclamencoum tuber extracts was evaluated via minimum inhibitory concentration) MIC( and minimum fungicidal concentration (MFC.(.

RESULTS

Our results demonstrated that ethyl acetate extract had no inhibitory effect on Candida strains, whereas the aqueous and n-butanolic extracts showed considerable activity. MIC and MFC of these extracts varied within the range of 2-32 µg/mL of saponin for different Candida samples. Aglyconic aqueous phase of the extract had the most effective anticandida activity. Glycosidic and aglyconic aqueous extracts were less active on C. albicans strains and C. Tropicalis, respectively.

CONCLUSION

Tuber extract of Cyclamen was rich in triterpenoid saponins and had antifungal effect. Sugar chain structure, as well as type and concentration of the aglycones were effective in this activity.

The evaluation of Candida albicans biofilms formation on silicone catheter, PVC and glass coated with titanium dioxide nanoparticles by XTT method and ATPase assay

Lots of Candida albicans infections involve in biofilm formation on medical devices. This kind of biofilm can impede antifungal therapy and complicates the treatment of infectious diseases particularly in field of chronic diseases associated with implanted devices. This study has investigated the influence of treating silicone catheter, PVC and glass coated with Titanium dioxide (TiO2) nanoparticles on attachment of C. albicans. In this study TiO2 nanoparticles were synthesized from precursor TiCl4 and characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD) which showed TiO2 nanoparticles are 70-100 nm in size. In the simplest model of biofilms formation, C. albicans isolates (ATCC10231) and (ATCC 76615) were grown on the surface of small disks of catheter, PVC and glass in a flat-bottomed 12-well plates and evaluated biofilm formation using ATP bioluminescence and tetrazolium salt (XTT) reduction assays. In addition, morphology of C. albicans biofilms after 48 h incubation was observed by SEM. Results indicated that there is a statistical difference between mean of coated samples especially catheter and glass before and after TiO2 nanoparticles coating (p<0.05). In SEM analysis, C. albicans biofilm was more aggregated on the surface of glass and catheter than PVC and control groups and after treatment by these nanoparticles, catheter and glass both showed most significant decrease of C. albicans attachment in comparison to the control groups (Fig. 4, Ref. 23).

Reproducibility of postural changes in intraocular pressure with the Tono-Pen and Pulsair tonometers

Reproducibility of measurements of postural changes in intraocular pressure was determined by using the Tono-Pen (Mentor O & O, Inc., Norwell, Massachusetts) and Pulsair (Keeler Instruments, Inc., Broomhall, Pennsylvania) tonometers. Thirty subjects had three repeated sitting and reclining measurements performed on three separate visit days. Reproducibility coefficients of 3.3% for the Tono-Pen and 6.3% for the Pulsair were obtained for the within-visit postural change measurements. Across-visit reproducibility coefficients were 7.9% and 26.2% for the Tono-Pen and Pulsair, respectively. The estimated standard deviations for both the within-visit and across-visit postural change measurements were high for both instruments. These results indicate poor reproducibility of measurements of postural changes in intraocular pressure.

[Consequences of a delayed start of therapy in primary irradiated gynecologic malignomas on five-year healing and mortality. A clinical epidemiological study]

The cases of 627 women with gynaecological malignomas, who were primarily irradiated in 1967 to 1969, were interpreted, questioning the temporary difference between clinical and histological diagnosis and beginning of treatment with regard to five-years' healing-results and mortality. The study has demonstrated, that - a delay of only four weeks considered - the part of living patients waas 11,28% of the total number of living patients, the part of dead patients however was 21,62% of the total number of dead patients. We emphasize therefore the urgency of an immediate beginning of therapy following a reliable diagnosis.