The lines forming outside Asda supermarkets across the UK early last November 9 weren't just for last-minute tea and toast. British consumers were spending their Saturday morning queuing up—some reports suggest even before stores were opened—to get stuck with PowderMed Ltd.'s Fluvirin influenza vaccine, at a cost of £12 ($19) each.
In fact, 35,000 Brits received Fluvirin at Asda stores on October 12. The success of the first stage of this...