【明報專訊】When I left home in January to go back to the US, I hoped that I wouldn't have to spend another fourteen days in expensive hotel quarantine. Five months on, the world is generally in a better place; in much of the rich world, a sizable portion of the population has been vaccinated. For example, more than one in two Americans has received at least one dose of the vaccine, and people are once again revelling in pleasures that would have been unthinkable during the pandemic. NBA stadiums bursting with the deafening cheers and jeers of fans; students back in classrooms; audiences back in cinemas chomping on popcorn; restaurants, once on the cusp of shutdown, are once again brimming with life. A headline in a French newspaper shouts ''On revit!'' (''We live again!''). While we should not disregard the huge disparities in access to vaccines between countries, as well as the inevitable threat of new variants, there is room for optimism.