(Bloomberg) -- European drug regulators say there’s some evidence of a link between AstraZeneca Plc’s Covid-19 vaccine and a rare type of blood clots, though occurrences are low. It’s up to individual countries to set guidelines, which means there’s no unified response, something that may confuse, or even worry, people due to receive the shot. Some countries are still using it on all adults for now, others are restricting to certain age groups, and a few have stopped it completely.