Countries phasing out AstraZeneca’s Covid vaccine appear to be responding to citizens’ personal fears, not scientific data to support such a move, said Dr. Ezekiel Emanuel told CNBC on Tuesday.

Germany, France and a growing list of other European nations have in the past few days stopped using the AstraZeneca vaccine, which was co-developed with Oxford University, for blood clots.

AstraZeneca’s two-shot vaccine has not been approved in the United States. Only Pfizer and Moderna’s two-shot Covid therapies and Johnson & Johnson’s single-dose vaccine have been approved by the FDA for emergency use in America.

“It may be that … governments are trying to respond to people’s concerns about the vaccine and not necessarily to the data,” Emanuel, former Covid advisor to President Joe Biden, told Squawk Box. “Actions don’t necessarily follow data. They follow more emotional responses to things like this,” added Emanuel, a bioethicist and oncologist who serves as the vice provost of global initiatives at the University of Pennsylvania.

Countries that have stopped giving AstraZeneca’s vaccine say the move is temporary while they investigate a possible link between the shot and a possible increased risk of blood clots. Some analysts fear that the decisions could permanently damage the reputation of the vaccine, and therefore public willingness to take it, even if no link is found.

AstraZeneca has defended its vaccine, saying in a statement on Sunday that it has reviewed safety records on more than 17 million people in the European Union and the UK who have received the vaccine. It was found that “there is no evidence of an increased risk of pulmonary embolism, deep vein thrombosis (DVT) or thrombocytopenia in any particular age group, gender, group or country”.

As of Sunday, AstraZeneca reported 15 cases of DVT and 22 cases of pulmonary embolism in people who took the Covid vaccine.

“The data are not overwhelming,” Emanuel said, explaining that it is difficult to know if the blood clots were caused by the shot in recipients, as the vaccine is now being given on a large scale to people without control, as in a clinical trial or mere coincidence.

“Remember, if you give it to a lot of old people, there will be a lot of other health problems these people have, and figuring out what the vaccine is from the background condition is a challenge,” said Emanuel, who also works as a health advisor of former President Barack Obama. “We are not seeing any increase in the proportion from what we would expect given the patient population receiving the vaccine,” added Emanuel. “Getting to the bottom of this will be the crucial problem.”

The European Medicines Agency approved the vaccine against Oxford-AstraZeneca at the end of January. Moderna’s vaccine was approved for use in the EU earlier this month. The vaccine developed jointly by Pfizer and BioNTech received the green light in the EU in December. The Johnson & Johnson vaccine was the last to receive EU approval on Thursday.

The pause in AstraZeneca’s vaccine delivery in some countries comes at a critical time in the pandemic. Some European nations, like Italy, are seeing a surge in new coronavirus cases and reinstating stricter public health precautions.

However, according to the European Center for Disease Prevention and Control, only around 9% of people aged 18 and over in the EU and the European Economic Area have had at least one Covid shot. According to ECDC data, around 4% of the vaccine-eligible population is fully vaccinated.

For comparison, 27.5% of the 18-year-old US population have received at least one dose of a coronavirus vaccine, according to the Centers for Disease Control and Prevention, with 14.8% fully vaccinated.

“It is a major concern that not so many people are being vaccinated in Europe,” said Emanuel, especially given the emerging virus variants. “It’s another reason we need to be concerned about the situation of Covid in other countries, not just the United States. Of course, we need to get people vaccinated in the US … but we need to be concerned be about other countries. “

The coronavirus situation in Europe no longer necessarily predicts what will happen in the US, said Dr. Scott Gottlieb told CNBC on Monday.

“I don’t think that the conditions in Europe and the situation in Europe inevitably predict what will happen here, as we in our population have much more immunity, both against previous infections – which they have – and now against vaccinations” added Gottlieb, a board member at Pfizer, which makes a Covid vaccine.