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Vaccination centers in Germany canceled thousands of appointments this week, after officials suspended use of the AstraZeneca vaccine.

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European countries resume use of AstraZeneca’s COVID-19 vaccine, hoping pause has not dented confidence

Science’s COVID-19 reporting is supported by the Heising-Simons Foundation.

A dozen European countries today said they will resume vaccinations with the AstraZeneca vaccine against COVID-19 after the European Medicines Agency (EMA) said its initial investigation of possible side effects has concluded the vaccine is “safe and effective.” Their decisions came as a relief to many public health experts, who worried about long delays in the COVID-19 vaccination programs at a time when cases are increasing in much of Europe.

At a press conference this afternoon, EMA officials said their inquiry could not rule out a connection between the vaccine and certain unusual clotting and bleeding disorders, but they concluded that the benefits of the vaccine clearly outweigh the risks. The agency will add a warning to the vaccine product information to alert patients and doctors to the potential side effects, which appear to be extremely rare.

More than 20 countries stopped vaccinations earlier this week following reports of mostly young patients who suffered severe clotting disorders and rare types of strokes shortly after receiving the AstraZeneca vaccine. Today, within hours of EMA’s statement, Germany, France, Italy, Spain, the Netherlands, and at least seven other countries said they will restart vaccinations as early as Friday.

EMA said it would continue its examination of the clotting and bleeding disorders. “The evidence we have is, at the moment, not sufficient to conclude with certainty whether these adverse events are indeed caused by the vaccine or not,” Sabina Straus, who chairs EMA’s Pharmacovigilance and Risk Assessment Committee, told the press conference. The committee will continue research on the events, says Peter Arlett, EMA’s head of pharmacovigilance, including further consultation with experts, studies of how common the clotting disorders are, and “lab tests to see if there is anything particular about these patients who are experiencing blood clots.”

EMA also said vaccinees who experience symptoms such as persistent bleeding, pain in the chest or stomach, severe or worsening headaches, or blurred vision should seek prompt medical assistance.

Some researchers have fretted that the pause, which dominated headlines across the continent this week, may further erode confidence in the AstraZeneca vaccine—which surveys suggest was already viewed as inferior to Pfizer’s and Moderna’s messenger RNA vaccines—or in COVID-19 vaccines in general. But the opposite may well be the case, says Stephan Lewandowsky, a risk communication expert at the University of Bristol. “You’ve got to keep the public on board,” Lewandowsky says. “And if the public is risk-averse, as it is in Europe … it may have been the right decision to stop, examine this carefully and then say, ‘The evidence, when considered transnationally, clearly indicates it is safe to go forward.’”

Others are not so sure. “At least in the short term, there have been some negative effects of this whole series of events on general vaccine acceptance with regards to COVID,” says Michael Bang Petersen, a political scientist at Aarhus University in Denmark, one of the first countries to suspend vaccinations. Petersen has been running a study that, for 1 week every month, surveys a representative sample of people in eight countries about their attitudes toward the pandemic, including vaccines. This month’s survey started on 10 March, coincidentally the day before Denmark put vaccinations with AstraZeneca on hold, allowing the researchers to compare attitudes before and after the announcement.

In a preprint posted today, Petersen reported the Danish decision caused vaccine confidence to drop by about 11% in Denmark itself and also to a lesser degree in other countries, and it decreased a little more when those countries themselves suspended vaccination. “What will buffer that short-term impact is trustworthy health communication,” Petersen says, such as clear messaging about the benefits of the vaccine and the small relative risk.

Cornelia Betsch, a psychologist who studies vaccination attitudes at the University of Erfurt in Germany, agrees communication over the next couple of days will be crucial for COVID-19 immunization programs. So far, in Germany at least, authorities have not excelled at that, she says. When the government announced the vaccination pause on Monday, it gave few details on the reasons at first. “They dropped the ball and ran away,” Betsch says.

Most of the cases of rare blood disorders were among young women, the group where vaccine hesitancy already runs highest, Betsch says. She thinks one way to address concerns among this group could be to give them preferential access to other vaccines.

*Correction, 19 March, 4:20 a.m.: An earlier version of this story said vaccine confidence in Denmark dropped by about 5% after the decision to suspend the use of the AstraZeneca vaccine in that country. It was an 11% drop.