IU: No Evidence of Blood Clots from AstraZeneca Vaccine Trial

(photo courtesy of the IU School of Medicine)

The leader of the clinical study of the COVID-19 vaccine from AstraZeneca plc (Nasdaq: AZN) at the Indiana University School of Medicine says there has been no evidence of any blood clot-related side effects from the vaccine in Indiana or throughout the country. The school last year was one of many sites selected to conduct the double-blind study and Associate Professor of Clinical Medicine Dr. Cynthia Brown says more than 530 Hoosiers have participated. The news comes on the same day health officials in Canada recommended halting the use of the vaccine in adults under 55 due to rare cases of serious blood clots.

During a virtual press briefing Tuesday morning, Brown noted that data is still being collected.

“None of these side effects were particularly picked up in the clinical trial,” said Brown. “But as you go from tens of thousands to hundreds of thousands or even millions of people receiving the vaccine, it is possible a rare, but serious side effect could show up and I think potentially honing in for the cause of a rare, but serious side effect, as well as any potentially risk factors that may be disposed for that will be important.”

Brown says it is important to let the scientific community try to determine if there are any risks of the vaccine before determining if it is something that should not be used worldwide.

The European Medicines Agency earlier this month ruled the AstraZeneca vaccine was “not associated with an increase in the overall risk of blood clots (thromboembolic events) in those who receive it,” after rollout of the vaccine was halted due to concerns.

“I think that this vaccine, because of the information not just collected in the clinical trials, but in the UK where it’s already being rolled out showing that in England and in Scotland that the decline in hospitalizations is significant after use of this vaccine and equivalent to individuals who receive the Pfizer vaccine, I think that there is a strong role for this vaccine around the world, particularly as we try to get it into low-income countries,” said Brown.

Brown says as AstraZeneca looks for a possible Emergency Use Authorization from the U.S. Food and Drug Administration, it will be important for the FDA to look at the data from the study and around the world.

“This particular vaccine is in a unique situation with the FDA because it has been rolled out in so many countries worldwide that there is additional data that’s not just from clinical trials,” she said. “So we have a lot of both real-world efficacy data, as well as real-world potential side effects data that the FDA is going to be able to scrutinize, which has not been available for any of the other vaccines that underwent EUA.”

Brown adds an EUA approval in the U.S. would provide confidence worldwide that the vaccine can be used.

When the study was first announced, the research team said its goal was to enroll Hoosiers who were representative of the demographics of Indianapolis. Brown says they were able to strongly recruit Latinx participants and individuals over the age of 65, but there is still work to do to better recruit participants from the Black community.

“Perhaps we should’ve done a better job up front in connecting with community leaders, our diversity and inclusion committees here at Indiana University that could have helped improve our enrollment. I think it’s really important, as the flagship university and medical school here in this state, that as a research community, we understand the potential barriers to enrollment, as well as how to make those connections.”

Brown says the research team will continue to follow up with participants for up to two years.