The Drug Controller General of India (DCGI) has authorised vaccine-maker Biological E’s Corbevax for emergency use among children aged 12-17, making a third shot available in the Covid inoculation drive for youngsters. The Centre has already placed a purchase order for 5 crore doses of Corbevax, likely to be available in all the states by February-end. This is the third vaccine to be given an emergency use nod for 12-17 year-olds after Bharat Biotech’s Covaxin and Zydus Cadila’s ZyCov-D.