ABSTRACT
Background: The continuous evolution of SARS-CoV-2 in the diverse immune landscape (natural, vaccine, hybrid) is giving rise to novel immune escape mutations. So far, the resulting new variants (BA.1, BA.2, BA.2.12.1) were observed to cause mild infections, however, BA.5 infections are associated with an increased risk of hospitalization.1 Therefore it is essential to investigate the pathogenesis of BA.5. Method(s): Here we compared the pathogenicity of Pre-Omicron (B.1.351) and Omicron (BA.1, BA.2.12.1, and BA.5) variants in wild-type C57BL/6J mice and K18-hACE2 mice. The virus replication kinetics was also studied in human Calu3, pulmonary alveolar type 2 (AT2) cells, and airway organoids (HAO). Cell-to-cell spread of virus was measured by syncytia formation assay and immunohistochemistry (IHC) of infected lungs. Result(s): In the results, infection in C57BL/6J mice showed severe weight loss ( >15%) for B.1.351 infected mice and moderate ( >5%) for BA.5 infected. C57BL/6J mice showed higher virus replication of B.1.351 followed by BA.5, BA.1, and BA.2.12.1. At the peak of virus replication (2 days) plaque-forming units from lung extract of BA.5 infected mice were two, and three logs higher compared to BA.1 and BA.2.12.1 respectively. BA.5 infection was lethal to 80% of infected K18-hACE2 mice, whereas the mice looked normal after infection with BA.1 and BA.2.12.1. BA.5 infected mice showed high virus replication in brain tissue. Surprisingly the syncytia formation assay and IHC for BA.5 was comparable to that of B.1.351, indicating the higher cell-to-cell spread of BA.5 and B.1.351 compared to BA.1 and BA.2.12.1, which is one of the measures of pathogenicity. Calu3 and HAO showed the same trend of virus replication as was observed in-vivo experiments however AT2 cells were found to be resistant to BA.5 replication. Conclusion(s): These results suggest that the BA.5 variant (lineage) of Omicron has the potential to regain the pathogenicity as it shows increased virulence compared to other Omicron sub-variants. Lethal infection of BA.5 in K18-hACE2 mice may be attributed to catastrophic encephalitis and increased cell-to-cell spread.
ABSTRACT
Background: Knowledge attitude practice study helps in improving the knowledge of the public, their awareness and promote positive message which could help in combating against Corona virus disease (COVID-19) or similar pandemic in future. Objectives: The objectives of the study were to assess knowledge, attitude and practices of residents and students towards COVID-19 pandemic in Chhindwara, Madhya Pradesh. Material and methods: This cross-sectional survey conducted in Chhindwara, Madhya Pradesh, from February 2021 to March 2021. Data was collected using Google form as an online survey. A self-designed questionnaire with four parts general instructions, knowledge, attitude and practice was prepared comprising of 07 questions on knowledge, 08 for attitude, and 08 for practice. Results: Out of the 164 participants, 48.78 % males, 51.21% females, 82.31% of 18-30 years and 15% ≥31 years. 71.34% were medical students and 28.65% paramedical staffs. 98.78% had correct knowledge about the spread of COVID-19, 97.53% about use of washing hands with soap and water and hand sanitizer. 97.54% avoided crowded places, 87.80% agreed vaccination can prevent spread of COVID-19 infection. 68.71% said they have not visited crowded places, 99.38% said spread of COVID-19 was social responsibility, 95.67% were wearing masks, 75.92% said vaccination will overcome the COVID-19. 92.40% avoided unnecessary travel, 94.93% wearing mask, 94.93% showed good practice, 94.87% encouraged social distancing at office, 89.74% avoided hand shaking. Significant difference found in practice score of different genders (P<0.004). Conclusion: The present study showed that participants had higher knowledge, positive attitude and good practices regarding COVID-19.