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Abstract Background and aims A healthy diet play an important role in the prevention and even treatment of various diseases. Proper nutrition plays an important role in boosting of immune system. These include the consumption of macronutrients such as proteins, lipids, carbohydrates, and also micronutrients including vitamins. Here, we aimed to systematically review the effects of macronutrients and micronutrients on the prevention and treatment of COVID-19. Methods We searched the databases of PubMed, Scopus, Embase, and Web of Science on December 23, 2023. The records were downloaded into an EndNote file, the duplicates were removed, and the studies underwent a two-phase screening process based on their title/abstracts and full texts. The included articles were screened and underwent inclusion and exclusion criteria. We included the English systematic reviews and meta-analyses that concurred with the aim of our study. The selected articles were assessed by Cochrane's Risk of Bias in Systematic Reviews for the quality check. The data of the eligible studies were extracted in a pre-designed word table and were used for the qualitative synthesis. Results A total of 28 reviews were included in this study. Most studies have shown that micronutrients are effective in morbidity and mortality controlling in viral respiratory infections such as COVID-19 but some studies have shown that micronutrients are sometimes not effective in controlling severity. On the other hand, calcifediol was by far the most successful agent in reducing intensive care needs and mortality between studies. Conclusion Individuals without malnutrition had a reduced risk of SARS-CoV-2 infection and severe disease. The administration of Vitamin D is effective in reducing the morbidity and mortality of COVID-19 patients. Patients with vitamin D deficiency were more prone to experience severe infection, and they were at higher risk of morbidities and mortality. Other micronutrients such as Vitamin A, Vitamin B, and Zinc also showed some benefits in patients with COVID-19. Vitamin C showed no efficacy in COVID-19 management even in intravenous form or in high doses.

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 × 10 6.25 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.

• Background: Absence of method for preserving ovarian function, especially in patients with cancer, is still unsolved in reproductive medicine. The aim of this study was to evaluate the effect of ovarian autotransplantion without vascular pedicle on the region of the neck in female rats. • Methods: 31 female rats were divided into three groups: sham (n = 10), ovariectomized (OVx) (n = 10) and transplant (T) (n = 11). In T group, ovaries were removed and transplanted into the neck close to jugular vein. Blood samples were taken on day 0, 7 and 21 after surgery. • Finding: Serum estradiol levels in OVx and T groups were decreased in day 7. The estradiol levels increased on day 21 in T group while in OVx group was decreased further. Serum FSH level in OVx group not in T group was significantly increased after day 7. Serum LH level on 7 and 21 days after surgery was increased in OVx and T groups. • Conclusion: It seems that ovarian autotransplant to the region of the neck without vascular pedicle maintains hormone secretion; however, it needs more study to validate this method.