Detection of the omicron variant in international travellers and their family contacts in India

HighlightsWith the emergence of the Variant of Concern, omicron (B.1.1.529), India has enhanced genomic surveillance in international travellers. The omicron variant was detected in 59 cases from different States; 40 from Maharashtra, 17 from Rajasthan and one each from Gujrat and Tamil Nadu. The positive cases and their contacts were asymptomatic and genomic surveillance could identify two clusters, one from Maharashtra and another from Rajasthan.

SARS-CoV-2 Delta variant pathogenesis and host response in Syrian hamsters

B.1.617 lineage is becoming a dominant SARS-CoV-2 lineage worldwide and was the dominant lineage reported in second COVID-19 wave in India, which necessitated studying the properties of the variant. We evaluated the pathogenicity and virus shedding of B.1.617.2 (Delta) and B.1.617.3 lineage of SARS-CoV-2 and compared with that of B.1, an early virus isolate with D614G mutation in Syrian hamster model. Viral load, antibody response and lung disease were studied. No significant difference in the virus shedding pattern was observed among these variants studied. A significantly high SARS-CoV-2 sub genomic RNA could be detected in the respiratory tract of hamsters infected with Delta variant for 14 days. Delta variant induced lung disease of moderate severity in 40% of infected animals. The neutralizing capability of the B.1, Delta and B.1.617.3 variant infected animals were found significantly lower with the B.1.351 (Beta variant). The findings of the study support the attributed disease severity and the increased transmission potential of the Delta variant.

Comparison of SARS-CoV-2 VOC 202012/01 (UK variant) and D614G variant transmission by different routes in Syrian hamsters

Many SARS-CoV-2 variants of concern has been reported recently which were linked to increased transmission. In our earlier study on virus shedding using VOC 202012/01(UK variant) and D614G variant in hamster model, we observed significantly higher viral RNA shedding through nasal wash in case of UK variant. Hence, we compared the transmission of both the UK and D614G variant by various routes in Syrian hamsters to understand whether the high viral RNA shedding could enhance the transmission efficiency of the variant. The current study demonstrated comparable transmission efficiency of both UK and D614G variants of SARS-CoV-2 in Syrian hamsters.