China has sent more than 100 planes to probe Taiwan’s air-defence zone. We explain why Beijing has chosen this moment to send a message across the strait. The WHO has approved a vaccine against malaria—a turning-point in fighting a disease that kills 260,000 African children a year. And if you want a Nobel prize, it helps to be lauded by a laureate.     For full access to print, digital and audio editions of The Economist, subscribe here www.economist.com/intelligenceoffer   See acast.com/privacy for privacy and opt-out information.