CORONAVIRUS | New US coronavirus cases could more than double to 100,000 per day if the current surge spirals further out of control, the government’s top infectious disease expert warned on Tuesday, although he was “cautiously optimistic” a vaccine would be available early next year.

California, Texas and Arizona have emerged as new epicentres of the pandemic, each reporting record increases in Covid-19 cases, adding to pressure on scores of potential vaccines being rushed into trials...