Delta, now a 'variant of concern,' accounts for 10 percent of new U.S. cases, CDC says
By Erika Edwards & Sara G. Miller
Boris Johnson extends current lockdown rules in England due to concerns over delta Covid variant
By Elliot Smith
Headache and runny nose linked to Delta variant
By Michelle Roberts
Delta variant doubles risk of COVID hospitalisation - Scottish study
By Nick Macfie & Alistair Smout