EXPLAINER: What we know about AstraZeneca blood clot reports

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. Most restarted — some with the kinds of restrictions Germany imposed Tuesday — after Europe's drug regulator said the benefits of the vaccine outweighed the risks of not inoculating people against COVID-19.

The seesawing back and forth on who can take the vaccine has raised concerns that its credibility could be permanently damaged. Here's a look at what we know — and what we don't.

WHAT HAPPENED IN GERMANY?

Earlier this week, Germany's medical regulator released new data showing a rise in reported cases of unusual kinds of blood clots in people who recently got a dose of the AstraZeneca vaccine. In response, Health Minister Jens Spahn and state officials agreed to only give the vaccine to people aged 60 or older, unless they are at high risk of developing serious complications from COVID-19 and have agreed to take the shot.

"It’s about weighing the risk of a side effect that is statistically small, but needs to be taken seriously, and the risk of falling ill with corona,” Spahn said.

Germany's medical regulator said its tally of the rare blood clots reported by March 29 had increased to 31. Some 2.7 million doses of AstraZeneca have been administered in Germany so far. Nine of the people died and all but two of the cases involved women, who were aged 20 to 63, the Paul Ehrlich Institute said.

Some clots have also been reported elsewhere, among the tens of millions of people who have received the AstraZeneca...