AstraZeneca announced Thursday it had doubled its annual profit in 2020 as the World Health Organization approved its coronavirus shot for over-65s, boosting the global immunisation effort against Covid-19.Mass vaccination programmes are being ramped up in many countries, but have been hampered by limited supplies as rising infections force governments to tighten virus restrictions.Also Read | Inside the Mindtree makeover strategyAstraZeneca was at the centre of a diplomatic spat between the EU and Britain earlier this year over supply problems, and also faced a setback when a number of European nations did not authorise its coronavirus shot for the over-65s -- the demographic most vulnerable to Covid-19."Despite the significant impact from.