BERLIN (AP) — German Chancellor Angela Merkel held a crisis meeting Thursday with state governors amid fresh concern over unusual blood clots reported in people who received AstraZeneca’s coronavirus vaccine.

Several German regions suspended use of the shots in people under 60, and the country’s independent vaccine expert panel recommended restricting them to people above that age after reviewing the latest data on the rare side-effects released by Germany’s medical regulator.

The news is a further blow to the vaccine, which is critical to Europe’s immunization campaign and a linchpin in the global strategy to get shots to poorer countries. It comes less than two weeks after the EU drug regulator said the vaccine does not increase the overall incidence of blood clots following a similar scare. The European Medicines Agency said at the time that the benefits of vaccination outweigh the risk, but it could not rule out a link between the shot and some unusual kinds of clots and recommended adding a warning about possible rare side-effects.

Authorities in Berlin, Munich, Brandenburg state and the country’s biggest state, North Rhine-Westphalia, made the decision to temporarily halt vaccinations for younger people after the country’s medical regulator said it had received additional reports of an unusual form of a blood clot in the head, known as sinus vein thrombosis, in recent recipients of the AstraZeneca vaccine.

Altogether, those areas are home to almost a third of the German population.

The Paul Ehrlich Institute said a total of 31 such blood clots were reported by March 29 out of some 2.7 million doses of AstraZeneca that have been administered across the whole of Germany so far. Nine of the people died and all but two of the cases involved women, who were aged 20 to 63, it said.

In a statement, AstraZeneca said that tens of millions of people worldwide have received its vaccines and noted the EMA’s conclusion that the benefits of the shot outweigh the risks.

The company said it would continue to work with German authorities to address any questions they might have, while also analyzing its own records to understand whether the rare blood clots reported occur more commonly “than would be expected naturally in a population of millions of people.”

The suspensions come as Germany, along with other European countries, is scrambling to ramp up its vaccine program, which lags far behind those in Britain and the United States. By Monday, some 13.2 million people in the country had received at least one dose of vaccine, while nearly 4 million had received both shots.

Use of the AstraZeneca vaccine was temporarily halted in several European countries earlier this month over concerns about the rare blood clots. After a review by medical experts at the European Medicines Agency, most European Union countries, including Germany, resumed use of the vaccine on March 19.

On Monday, Canada suspended use of the AstraZeneca vaccine in people under 55, citing new concerning data from Europe.

“There is substantial uncertainty about the benefit of providing AstraZeneca COVID-19 vaccines to adults under 55 given the potential risks,” said Dr. Shelley Deeks, vice chair of Canada’s National Advisory Committee on Immunization.

Deeks said the updated recommendations come amid new data from Europe that suggests the risk of blood clots is now potentially as high as one in 100,000, much higher than the one in one million risk believed before.

Two state-owned hospitals in Berlin announced Tuesday that they had stopped giving the AstraZeneca vaccine to female staff members under 55. The heads of five university hospitals in western Germany called for a temporary halt to the vaccine for all younger women, citing the blood clot risk.

Berlin state’s top health official, Dilek Kalayci, said the suspension of AstraZeneca vaccines for younger people was done as a precaution.

“We have not had a case of serious side-effects in Berlin yet,” she said, adding that all of those who had received the AstraZeneca shot already could rest assured that it provides good protection against the coronavirus.

“Still, we need to treat it carefully and wait for the talks taking place at the federal level,” said Kalayci.

The decision could affect appointments for tens of thousands of teachers and people with preexisting conditions who received invitations to get vaccinated in Germany’s capital in recent days. Appointments for the AstraZeneca shot were available sooner than ones for the vaccines made by Pfizer-BioNTech and Moderna.

German news agency dpa quoted a spokesman for Munich, the country’s third-largest city, saying that the suspension of AstraZeneca vaccinations for people younger than 60 would last “until the issue of possible vaccine complications for this group of persons has been resolved.”

Scientists at the University of Greifswald, Germany, this week published the results of their investigation into the possible causes of the blood clots, saying the condition is similar to a side-effect seen in some patients who receive the blood-thinning medication heparin.

The study, which hasn’t been peer-reviewed yet, doesn’t provide a conclusive explanation for why some people vaccinated with the AstraZeneca shot develop the rare blood clots. Still, experts not involved in the study said it offers important information to doctors.

Alice Assinger, a specialist in vascular diseases and blood clot research at the Medical University of Vienna, said there is a treatment for the rare clots.

A further concern is that the latest hitch may further dent the shot’s reputation in the public eye.

The leader of the Norwegian Association for General Practice, Marte Kvittum Tangen, told Norway broadcaster NRK last week that while “there is no report of a general vaccine resistance … people clearly say that they do not want the AstraZeneca vaccine. There is a lot of uncertainty and skepticism.”

Initially, several European countries hesitated to give the AstraZeneca shot to older people, citing a lack of data from the company about the vaccine’s effectiveness in those aged 65 and over. Subsequent studies showing it works in older people prompted most countries to approve it for those age groups.


AP medical writer Maria Cheng in London contributed to this report.