Blood clot concerns related to AstraZeneca vaccine not present in U.S. trials, UW Health says

MILWAUKEE (CBS 58) -- Dr. Bill Hartman heads the UW Health AstraZeneca clinical trial.

As the trial's principal investigator, he said none of their nearly 400 patients developed blood clots.

Concern of blood clots has caused several countries in Europe to suspend administering the vaccine. Hartman said 35 patients developed clots of the 17 million who received the vaccine globally.

“This is a very small percentage overall," Hartman said. "Smaller than what you would expect in the general public. But enough that the general public has decided to take a pause.”

Astrazeneca has not applied for FDA approval yet. Lisa Grabert, with the Marquette College of Nursing, said the company’s initial research didn’t align with the U.S. emphasis on vaccinating the elderly.

“That’s part of why they weren’t necessarily ready for U.S. approval, because that’s a really important population in the United States," Grabert said. "That’s been one of our first priority populations.”

UW Health joined other trials in recently sending results from the 31 thousand U.S. participants to AstraZeneca, which Hartman said should help answer questions about the 65 and older group.

“That has been given to them, so I would anticipate in the next couple of weeks getting a report indicating what the efficacy was in the United States,” Hartman said.

Grabert said that puts it on track for U.S. use in about a month.

She says the current issues in Europe show there are benefits to the United States' methodical approach toward vaccine approval.

“When you kind of rush the process a little bit, these kind of unintended consequences might come up, and it’s really unfortunate.”

The Biden administration is sitting on more than 10 million AstraZeneca vaccines. If it is approved, those could be rolled out almost immediately.