Some Canadians may be looking at the reopening in the U.K. with some envy but not so fast, says U.K. epidemiologist Dr. Deepti Gurdasani. The delta variant, also known as B1617, first identified in India, is driving a new COVID wave in the U.K. — and it's spreading quickly around the world, including in Canada. Gurdasani has stark advice to Canadian officials: act now to contain this variant or a fourth wave is likely coming.