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Omicron replicates 70 times faster than delta in airways, but lung infection appears less severe, study says
By Spencer Kimball
How Omicron spreads so fast is the question of the moment. New research is pointing to the answer
By Lauren Pelley
Lung tissue study sheds light on fast Omicron spread
By Lisa Schnirring
Omicron more likely to reinfect than Delta, no milder -study
By Clara-Læïla Laudette
'No evidence' Omicron less severe than Delta, say UK researchers
By John Burn-Murdoch, Sebastian Payne & Oliver Barnes
Omicron variant: What we know — and don't know
By Denise Chow
Omicron: What can we learn from South Africa's experience so far?
By Rachel Schraer & Peter Mwai
What We Know About the COVID-19 Omicron Variant
By Ashley Abramson
COVID-19 vaccines may be less effective against Omicron - WHO
By Hugh Lawson, Josephine Mason & Michael Shields