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Omicron variants are still the dominant SARS-CoV-2 viruses worldwide, therefore determining the level of protection from infection and severe disease is essential. Here, we investigated humoral and cellular immunity of individuals immunized by ChAdOx1, BNT162b2 and mRNA-1273 and our results show that IgG and neutralization titers wane over time. However, strongest neutralization against Omicron BA.1 and T cell responses were detected in ChAdOx1 vaccinees six months after the second dose, while no long lasting neutralization was shown against BA.2 in any cohort. Crucially, our investigation revealed that immunity against variants of concern is heterogenic and dependent on the immunization status. [ABSTRACT FROM AUTHOR]

Although much is already known about the exaggerated host immune response in severe COVID-19 disease, little is known about the relationship between this dysregulated immune response and the extent of brain injury. This scientific commentary refers to 'Brain injury in COVID-19 is associated with dysregulated innate and adaptive immune responses' by Needham I et al. i (https://doi.org/10.1093/brain/awac321). [Extracted from the article]

A letter to the editor is presented in response to the article "Commentary: Raising the Bar on Telomere Epidemiology," by A. Aviv which was published in the Volume 38, 2009 issue of the "International Journal of Epidemiology."

Background. Molecular mechanisms involved in the pathogenesis of severe Plasmodium falciparum malaria—specifically, cerebral malaria—are still unclear. Transforming growth factor b (TGF-b) family members are important regulators of inflammation that influence malaria pathogenesis. The soluble form of the auxiliary receptor endoglin (sEng) may play a role in malaria pathogenesis. Methods. Serum levels of sEng were measured using enzyme-linked immunosorbent-assay in Gabonese children with cerebral malaria (n = 7), severe malaria (n = 43), or uncomplicated malaria (n = 43) and were compared with levels in healthy control subjects (n = 25) and in another infectious disease group (n = 8). Results. Serum sEng levels were higher in patients with cerebral malaria and all patients with severe malaria when compared with levels in patients in the other infection group and the healthy control group. Furthermore, sEng correlated significantly with disease severity. Only 7% of patients with uncomplicated malaria and none of the control patients (patients in the other infection group or the healthy control group) had serum levels higher than 12 ng/mL, whereas this was found in 85.7% of patients with cerebral malaria and 46.5% of patients with severe malaria. Conclusions. High sEng levels may attenuate anti-inflammatory response resulting in clinical deterioration of patients with P. falciparum malaria. Our results further corroborate the role of the vascular compartment, especially the endothelium, in severe malaria pathogenesis. [ABSTRACT FROM AUTHOR]

Background Telomeres play a key role in the maintenance of chromosome integrity. Short telomeres are linked to age-associated diseases and cancer. Our aim was to determine the decrease rate of relative telomere length (RTL) over 10 years and whether this rate was influenced by age, sex and smoking behaviour. [ABSTRACT FROM PUBLISHER]

Background. Molecular mechanisms involved in the pathogenesis of severe malaria caused by Plasmodium falciparum are not fully understood. Matrix metalloproteinases (MMPs) are enzymes that proteolytically degrade both the extracellular matrix and nonmatrix substances with various functions in the modulation of immune response. The key inhibitors of MMPs are the tissue inhibitors of metalloproteinases (TIMPs). Methods. We studied levels of MMP-8, MMP-9, TIMP-1, and TIMP-2 on admission and after 24 h, using an enzyme-linked immunosorbent assay, in serum specimens from 50 Gabonese children with severe malaria, 43 children with uncomplicated malaria, and 27 healthy control children. Results. Serum MMP-8 and TIMP-1 levels were significantly higher in the severe malaria and uncomplicated malaria groups, compared with those in the control group (P < .001). TIMP-1 levels were significantly higher in patients with severe malaria, compared with those in patients with uncomplicated malaria (P < .001). High TIMP-1 levels were significantly correlated with malaria severity, as determined by the simplified multiorgan dysfunction score (Spearman rank-correlation coefficient, 0.55; P < .001). Conclusions. TIMP-1 is associated with signs and symptoms of severe malaria. MMP-8 levels are elevated in patients with severe or uncomplicated P. palciparum malaria. MMPs and TIMPs may be relevant in the pathogenesis of severe malaria, either as proteolytic enzymes that degrade the extracellular matrix or as effectors and regulators of the immune response. [ABSTRACT FROM AUTHOR]