Severity of the Omicron SARS-CoV-2 variant compared with the previous lineages: A systematic review.

The Omicron variant was first detected in October 2021, which evolved from the original SARS-CoV-2 strain and was found to possess many mutations. Immune evasion was one of the notable consequences of these mutations. Despite Omicron exhibiting increased transmissibility, the rates of hospitalizations and deaths among patients infected with this variant were substantially lower when compared to other strains. However, concluding that the Omicron variant is less severe than other variants of SARS-CoV-2 requires consideration of multiple factors, including the vaccination status of infected patients as well as any previous infections with other variants. This review compiled data about any reported indicators of severity in Omicron-infected patients, including studies comparing Omicron with other variants while adjusting for confounders. A comprehensive search was conducted using different databases to target any studies about Omicron. In total, 62 studies met our inclusion criteria and were included in this study. Many studies reported a significantly reduced risk of hospitalization, ICU admission, need for oxygenation/ventilation, and death in Omicron-infected patients compared to patients infected with other variants, such as Delta. Some studies, however, reported comparable severity in Omicron infected patients as to other variants emphasizing a substantial risk for severe illness. Furthermore, the COVID-19 vaccines were less effective against Omicron relative to previous lineages, except after receiving the booster dose. One study recommended vaccination during pregnancy, which may help prevent future cases of severe SARS-CoV-2 pneumonia in neonates and young infants due to the transfer of humoral response from the mother.

Effectiveness of the pre-Omicron COVID-19 vaccines against Omicron in reducing infection, hospitalization, severity, and mortality compared to Delta and other variants: A systematic review.

Despite widespread mass rollout programs, the rapid spread of the SARS-CoV-2 Omicron variant called into question the effectiveness of the existing vaccines against infection, hospitalization, severity, and mortality compared to previous variants. This systematic review summarizes and compares the effectiveness of the COVID-19 vaccines, with respect to the above outcomes in adults, children, and adolescents. A comprehensive literature search was undertaken on several databases. Only 51 studies met our inclusion criteria, revealing that the protection from primary vaccination against Omicron infection is inferior to protection against Delta and Alpha infections and wanes faster over time. However, mRNA vaccine boosters were reported to reestablish effectiveness, although to a lower extent against Omicron. Nonetheless, primary vaccination was shown to preserve strong protection against Omicron-associated hospitalization, severity, and death, even months after last dose. However, boosters provide more robust and longer-lasting protection against hospitalizations due to Omicron as compared to only primary series.

Cancer Patients and the COVID-19 Vaccines: Considerations and Challenges.

Few guidelines exist for COVID-19 vaccination amongst cancer patients, fostering uncertainty regarding the immunogenicity, safety, and effects of cancer therapies on vaccination, which this review aims to address. A literature review was conducted to include the latest articles covering the immunogenicity and safety of COVID-19 vaccination in patients with solid and hematologic cancers receiving various treatments. Lower seropositivity following vaccination was associated with malignancy (compared to the general population), and hematologic malignancy (compared to solid cancers). Patients receiving active cancer therapy (unspecified), chemotherapy, radiotherapy, and immunosuppressants generally demonstrated lower seropositivity compared to healthy controls; though checkpoint inhibition, endocrine therapy, and cyclin dependent kinase inhibition did not appear to affect seropositivity. Vaccination appeared safe and well-tolerated in patients with current or past cancer and those undergoing treatment. Adverse events were comparable to the general population, but inflammatory lymphadenopathy following vaccination was commonly reported and may be mistaken for malignant etiology. Additionally, radiation recall phenomenon was sporadically reported in patients who had received radiotherapy. Overall, while seropositivity rates were decreased, cancer patients showed capacity to generate safe and effective immune responses to COVID-19 vaccination, thus vaccination should be encouraged and hesitancy should be addressed in this population.

Anaphylaxis and Related Events Following COVID-19 Vaccination: A Systematic Review.

The coronavirus disease 2019 (COVID-19), induced by the severe acute respiratory syndrome coronavirus 2, is responsible for a global pandemic following widespread transmission and death. Several vaccines have been developed to counter this public health crisis using both novel and conventional methods. Following approval based on promising efficacy and safety data, the AstraZeneca, Janssen, Moderna, Pfizer/BioNTech, and Sinovac vaccines have been administered globally among different populations with various reported side effects. Reports of life-threatening anaphylaxis following administration were of particular concern for both health care providers and the public. A systematic literature search using PubMed, Embase, Scopus, Web of Science, Science Direct, MedRxiv, and Lens.org databases identified relevant studies reporting anaphylaxis following vaccine administration. This systematic review includes 41 studies reporting anaphylaxis. A total of 7942 cases, including 43 deaths, were reported across 14 countries. Most cases occurred following the administration of the first dose. Importantly, the benefits of vaccination outweigh the risks of anaphylaxis. Subsequently, as populations continue to get vaccinated, it is important for health care providers to be able to recognize individuals at risk of developing anaphylaxis. Furthermore, they must be familiar with both the clinical hallmarks and treatment of anaphylactic reactions to minimize long-term sequalae and prevent death in vaccinated individuals.

Metformin: Is it a drug for all reasons and diseases?

Metformin was first used to treat type 2 diabetes in the late 1950s and in 2022 remains the first-choice drug used daily by approximately 150 million people. An accumulation of positive pre-clinical and clinical data has stimulated interest in re-purposing metformin to treat a variety of diseases including COVID-19. In polycystic ovary syndrome metformin improves insulin sensitivity. In type 1 diabetes metformin may help reduce the insulin dose. Meta-analysis and data from pre-clinical and clinical studies link metformin to a reduction in the incidence of cancer. Clinical trials, including MILES (Metformin In Longevity Study), and TAME (Targeting Aging with Metformin), have been designed to determine if metformin can offset aging and extend lifespan. Pre-clinical and clinical data suggest that metformin, via suppression of pro-inflammatory pathways, protection of mitochondria and vascular function, and direct actions on neuronal stem cells, may protect against neurodegenerative diseases. Metformin has also been studied for its anti-bacterial, -viral, -malaria efficacy. Collectively, these data raise the question: Is metformin a drug for all diseases? It remains unclear as to whether all of these putative beneficial effects are secondary to its actions as an anti-hyperglycemic and insulin-sensitizing drug, or result from other cellular actions, including inhibition of mTOR (mammalian target for rapamycin), or direct anti-viral actions. Clarification is also sought as to whether data from ex vivo studies based on the use of high concentrations of metformin can be translated into clinical benefits, or whether they reflect a 'Paracelsus' effect. The environmental impact of metformin, a drug with no known metabolites, is another emerging issue that has been linked to endocrine disruption in fish, and extensive use in T2D has also raised concerns over effects on human reproduction. The objectives for this review are to: 1) evaluate the putative mechanism(s) of action of metformin; 2) analyze the controversial evidence for metformin's effectiveness in the treatment of diseases other than type 2 diabetes; 3) assess the reproducibility of the data, and finally 4) reach an informed conclusion as to whether metformin is a drug for all diseases and reasons. We conclude that the primary clinical benefits of metformin result from its insulin-sensitizing and antihyperglycaemic effects that secondarily contribute to a reduced risk of a number of diseases and thereby enhancing healthspan. However, benefits like improving vascular endothelial function that are independent of effects on glucose homeostasis add to metformin's therapeutic actions.

Lymphadenopathy post-COVID-19 vaccination with increased FDG uptake may be falsely attributed to oncological disorders: A systematic review.

Coronavirus disease 2019 (COVID-19) has caused a global pandemic that continues to cause numerous deaths to date. Four vaccines have been approved by the Food and Drug Administration as of July 2021 to prevent the transmission of COVID-19: Pfizer, Moderna, AstraZeneca, and Janssen. These vaccines have shown great efficacy and safety profile. One side effect that has been widely reported is post-COVID-19 vaccination lymphadenopathy. Due to the mimicry of the lymphadenopathy for metastases in some oncologic patients, there have been reports of patients who underwent biopsies that showed pathologic confirmation of benign reactive lymphadenopathy secondary to the COVID-19 vaccine. Therefore, understanding the incidence of lymphadenopathy post-COVID-19 vaccinations will help guide radiologists and oncologists in their management of patients, both present oncologic patients, and patients with concerns over their newly presenting lymphadenopathy. A systematic literature search was performed using several databases to identify relevant studies that reported lymphadenopathy post-COVID-19 vaccination. Our results revealed that several cases have been detected in patients undergoing follow-up fluorodeoxyglucose (FDG)-positron emission tomography-computerized tomography scans where lymph nodes ipsilateral to the vaccine injection site show increased uptake of FDG. Thus, knowledge of the incidence of lymphadenopathy may help avoid unnecessary biopsies, interventions, and changes in management for patients, especially oncologic patients who are at risk for malignancies.