Canadian health officials said on Monday they would stop offering AstraZeneca's Covid-19 vaccine to people under age 55 and require a new analysis of the shot's benefits and risks based on age and gender.

The moves follow reports from Europe of rare but serious blood clots, bleeding and in some cases death after vaccination, mainly in young women. No such cases have been reported in Canada, with about 307,000 AstraZeneca doses administered...