If one thing unites the world, it is the desire for a quick exit from the coronavirus pandemic. Donald Trump shares that goal. But the US president’s reach is considerably longer than his grasp. His focus on antimalarial drugs as a cure for Covid-19 comes increasingly at the expense of the US government’s attention to more practical ends.

In Mr Trump’s view, a cocktail of hydroxychloroquine, the antimalarial drug, and azithromycin, an antibiotic, could be “one of the biggest game changers in the history of medicine”. His hunch is echoed by a motley crew of TV commentators, White House advisers and Rudy Giuliani, his personal lawyer. What they have in common is a lack of scientific credentials. By contrast, Dr Anthony Fauci, the US government’s most senior immunologist, describes the theory as a “majestic leap”. Other medical experts are less polite.

It is possible the cocktail may have some therapeutic benefits. Trials are under way. What we do know for sure is that widespread testing is a prerequisite to dilution of the lockdowns. The US is behind many other nations in making tests available to its people.