Interferon-gamma gene diplotype (AA-rs2069716 / AG-rs2069727) may play an important role during secondary outcomes of severe dengue in Brazilian patients: Interferon-gamma gene diplotype (AA-rs2069716 / AG-rs2069727) may play an important role during secondary outcomes of severe dengue in Brazilian patients

Dengue is a global and growing health threat, especially in Southeast Asia, West Pacific and South America. Infection by the dengue virus (DENV) results in dengue fever, which can evolve to severe forms. Cytokines, especially interferons, are involved in the immunopathogenesis of dengue fever, and so may influence the disease outcomes. The aim of this study was to investigate the association between severe forms of dengue and two single nucleotide polymorphisms (SNPs) in the interferon-gamma gene (IFNG): A256G (rs2069716) and A325G (rs2069727). We included 274 patients infected with DENV serotype 3: 119 cases of dengue without warning signs (DWoWS), and 155 with warning signs (DWWS) or severe dengue (SD). DNA was extracted, and genotyped with Illumina Genotyping Kit or real time PCR (TaqMan probes). We estimated the adjusted Odds Ratios (OR) by multivariate logistic regression models. When comparing with the ancestral AA/AA diplotype (A256G/A325G), we found a protective association of the AA/AG against DWWS/SD among patients with secondary dengue (OR 0.51; 95% IC 0.24-1.10, p = 0.085), adjusting for age and sex. The variant genotype at locus A325G of the IFNG, in combination with the ancestral genotype at locus A256G, can protect against severe clinical forms of secondary dengue in Brazilian DENV3-infected patients

Assessment of clinical characteristics and viral load in individuals infected by Delta and Omicron variants of SARS-CoV-2

In late 2021, a new variant of SARS-CoV-2 called Omicron emerged, replacing Delta worldwide. Although it has been associated with a lower risk of hospitalization and severe forms of COVID-19, there is little evidence of its relationship with specific symptoms and viral load. The aim of this study was to verify the relationship between Delta and Omicron variants of concern, viral load, and the occurrence of symptoms in individuals with COVID-19. Nasopharyngeal swab samples were collected and sequenced from patients with COVID-19 from the Northeast Region of Brazil between August 2021 and March 2022. The results showed a gradual replacement of the Delta variant by the Omicron variant during the study period. A total of 316 samples (157 Delta and 159 Omicron) were included. There was a higher prevalence of symptoms in Delta-infected individuals, such as coryza, olfactory and taste disturbances, headache, and myalgia. There was no association between viral load and the variants analyzed. The results reported here contribute to the understanding of the symptoms associated with the Delta and Omicron variants in individuals affected by COVID-19