ABSTRACT
Background: The incidence of breakthrough infection with the emergence of new variants of concern of SARS?CoV?2 is posing a threat, and it is pertinent to understand the role of vaccines in protecting the elderly and people with comorbidities. Objective: The present study was undertaken to understand the natural history of SARS?CoV?2 infection in a closed cohort of the elderly population in an old?age home who have received two doses of COVID?19 vaccination. The study has also undertaken genomic sequencing to identify SARS?CoV?2 variants of concern from an academic perspective. Materials and Methods: A prospective observational study was conducted from March to August 2021 among residents of 11 old?age homes in Kerala who were vaccinated with 2 doses of the COVID?19 vaccine, from 2 weeks following vaccination. Samples with a threshold cycle value of <25 were subjected to targeted sequencing of the spike protein receptor?binding domain coding region. Results: Among the 479 vaccinated individuals, 86 (17.95%) turned positive during the follow?up period. The mean duration of symptoms was 3–5 days, and no hospitalization was required. A phylogenetic analysis of the nucleotide sequences from the samples indicated B.1.617.2 lineage representing the Delta strain. Conclusion: The evidence supports maximizing the vaccine coverage among vulnerable groups to prevent hospitalization and death rate on the verge of the emergence of new variants of SARS?CoV?2.
ABSTRACT
Foot-and-mouth disease virus (FMDV) serotype O is the most predominant among the endemic serotypes in India. A stable, full-length cDNA clone of FMDV type O 1 BFS 1860 preceded by a bacteriophage T7 polymerase promoter was assembled in a plasmid vector pGEMR-7Zf(–). An ~8.2 kb PCR product was amplifi ed from the cDNA clone and a full-length RNA was generated from it by in vitro transcription. Transfection of BHK-21 cells with the in vitro transcripts resulted in the production of infectious recombinant FMDV particles as evidenced by cytopathic effects (CPE). Further, characterization of the recombinant virus by immunofl uorescence, microneutralization test (MNT), antigen ELISA, RT-PCR, plaque assay and electron microscopy revealed similarity to the parental strain. The immunogenicity of an oil-adjuvant vaccine prepared using the inactivated recombinant virus was tested in guinea pigs and cattle. Neutralizing antibodies were produced in both vaccinated guinea pigs and cattle. Vaccinated animals were protected on challenge. The results demonstrated that the recombinant virus was as stable and effective as the parental strain for the preparation of inactivated vaccine, suggesting the potential application of this strategy to make genetically engineered FMDV vaccines.