Immunity against coronavirus may only last a few months after infection, according to researchers at Imperial College London. They say the number of people testing positive for antibodies fell by around a quarter between June and September, with the biggest drop in those over 65. They’re warning everyone to adhere to guidance on hygiene, social distancing and so on, even if they’ve already had the virus. The researchers say their findings don’t scupper hopes of a vaccine, which may prove more effective than a real infection. Read more on the hunt for a vaccine.