RBD mutations at the residues K417, E484, N501 reduced immunoreactivity with antisera from vaccinated and COVID-19 recovered patients.

Introduction: It is unclear whether induced spike protein-specific antibodies due to infections with SARS-CoV-2 or to the prototypic Wuhan isolate-based vaccination can immune-react with the emerging variants of SARS-CoV-2. Aim/objectives: The main objective of the study was to measure the immunoreactivity of induced antibodies postvaccination with Covishield™ (ChAdOx1 nCoV-19 coronavirus vaccines) or infections with SARS-CoV-2 by using selected peptides of the spike protein of wild type and variants of SARS-CoV-2. Methodology: Thirty patients who had recovered from SARS-CoV-2 infections and 30 individuals vaccinated with both doses of Covishield™ were recruited for the study. Venous blood samples (5 mL) were collected at a single time point from patients within 3-4 weeks of recovery from SARS-CoV-2 infections or receiving both doses of Covishield™ vaccines. The serum levels of total immunoglobulin were measured in both study groups. A total of 12 peptides of 10 to 24 amino acids length spanning to the receptor-binding domain (RBD) of wild type of SARS-CoV-2 and their variants were synthesized. The serum levels of immune-reactive antibodies were measured using these peptides. Results: The serum levels of total antibodies were found to be significantly (p<0.001) higher in the vaccinated individuals as compared to COVID-19 recovered patients. Our study reported that the mutations in the RBD at the residues K417, E484, and N501 have been associated with reduced immunoreactivity with anti-sera of vaccinated people and COVID-19 recovered patients. Conclusion: The amino acid substitutions at the RBD of SARS-CoV-2 have been associated with a higher potential to escape the humoral immune response.

Dengue encephalopathy - still an enigma?

Dengue encephalopathy or dengue hemorrhagic fever (DHF) with neurological involvement was once considered to be one of the rarer presentations of this infectious agent. In recent years, many such clinical cases have been reported, though they still remain isolated. We hereby report a case of confirmed dengue fever with features of encephalopathy with previously unreported cranial magnetic resonance imaging findings suggestive of extensive involvement of the bilateral cerebellar region, brainstem, and thalami along with peculiar rim enhancement but normal cerebrospinal fluid analysis.