1 in 4 People Scheduled for AstraZeneca Vaccine in Croatia Not Showing Up

One in four people in Croatia who were scheduled to receive the AstraZeneca vaccine did not show up for their appointment on Thursday, after the European Union's medicines regulator said there was a possible link between the vaccine and a rare blood clotting disorder.

On Wednesday, the European Medicines Agency (EMA), said an unusual blood clotting disorder would be added as a "very rare" side effect from the vaccine following an in-depth analysis of the shot.

But despite those possibilities, both the European regulator and the U.K.'s Medicines and Healthcare Products Regulatory Agency stressed that the benefits of the vaccine outweigh the risks.

"The reported combination of blood clots and low blood platelets is very rare, and the overall benefits of the vaccine in preventing COVID-19 outweigh the risks of side effects," the EMA said in a Wednesday statement.

Nonetheless, the news has caused vaccine hesitancy across Europe, and has prompted several governments to implement different policies when administering the shots, the Associated Press reported.

For more reporting from Newsweek's Katherine Fung, see below:

Guidance for younger people as to whether or not they should get the AstraZeneca shot has shifted recently.

Most of the cases of blood clots that have been reported have occurred in women under 60 years of age within two weeks of vaccination. But the EMA's review has not yet determined a clear risk profile in the age and gender of those reporting such adverse reactions.

The EMA said its recommendations for use of the vaccine are not changing and called on those receiving the vaccine "to remain aware of the possibility of very rare cases of blood clots combined with low levels of blood platelets occurring within 2 weeks of vaccination."

The European Union's medicine regulator said that one reasonable explanation for blood clots and low blood platelets, another rare side effect, is that "immune response, leading to a condition similar to one seen sometimes in patients treated with heparin (heparin induced thrombocytopenia, HIT)."

EMA's decision follows last week's news from Germany and Canada, which suspended the use of the AstraZeneca vaccine in people under 60 and 55, respectively.

1 in 4 people in Croatia did not show up for the AstraZeneca shot on Thursday, after the EMA said the vaccine could be linked to a rare blood clotting disorder. Here, medical Staff handle an empty vial of the AstraZeneca vaccine against Covid-19 at a vaccination center at the Messe trade fair grounds during the third wave of the coronavirus pandemic on April 8, 2021 in Erfurt, Germany. Jens Schlueter/Getty Images

For more reporting from the Associated Press, see below:

Poland, too, has also seen people cancel or not appear for appointments to get the vaccine.

French general practitioner Dr. Joel Valendoff said many of his patients were still coming to get their shot, but many others were canceling.

When vaccines first became available, "I was refusing people because I had a lot of demand and not enough vaccines. Today I am facing the opposite. I have vaccines but not enough volunteers."

European Commission spokesman Stefan De Keersmaecker said the EMA's findings were based on its stringent monitoring system and that should promote trust among the bloc's 27 member states.

"We want to avoid, of course, a vaccination hesitancy," he said.

Any such reluctance is worrying since experts say the shots are key to stamping out the coronavirus pandemic, but AstraZeneca's role is especially vital. The vaccine, which is cheaper and easier to store than many others, is critical to immunization campaigns in Europe and the U.K. and is also a pillar of the U.N.-backed program known as COVAX that aims to get vaccines to some of the world's poorest countries.