After the first few cases of the Omicron Covid-19 variant found in India, we asked Polly Roy, professor of virology at the London School of Hygiene & Tropical Medicine, why there is so much worry about this particular strain, given that the world has known the Covid-19 virus for nearly two years now, and that it was always expected that more variants would emerge. Roy says the variant may not be as dangerous as people fear and that disease outcomes, as with any variant, depend on individual immunity. Vaccination is the best path to beat all variants, she says, and adds that she is confident about the efficacy of existing Covid-19 vaccines against Omicron.