LONDON (AP) — German officials have decided to limit the use of AstraZeneca’s coronavirus vaccine in people under 60 after more unusual blood clots were reported in a small number of people who received the shots. Earlier this month, more than a dozen countries, including Germany, suspended their use of AstraZeneca over the blood clot issue. After Europe’s drug regulator said the benefits of the vaccine outweighed the risks, most restarted, though some imposed the kinds of restrictions Germany has. The seesawing back and forth on who can take the vaccine has raised concerns that its credibility could be permanently damaged.