We need a global roadmap to vaccinate the world — and we need it now. The scenes emerging from India are a harrowing reminder that unequal distribution of vaccines puts everyone at risk. More contagious forms of the virus are already evolving, increasing the risk of a new mutation that resists current vaccines. Global access to vaccines is the fastest way to end the pandemic, but if rich countries monopolise supply and only vaccinate themselves, twice as many people could...