What could be the fourth approved coronavirus vaccine is the first to spark a significant debate over side effects.

The AstraZeneca vaccine is cheaper and easier to store than its predecessors, and is awaiting approval from the F-D-A. But several European countries which had approved the vaccine suspended its use after a few dozen cases of a rare blood clotting disorder, some of them fatal. On Tuesday, Canada barred the vaccine for patients under 55, while Germany limited its use to patients over 60.

The I-U School of Medicine was among the clinical-trial sites for the AstraZeneca vaccine. Researcher Cynthia Brown says the disorder hasn’t surfaced among the 530 patients there, nor at about 100 other U-S sites.

Brown says as long as you don’t have a history of clotting issues, she believes the vaccine’s benefits still outweigh any risk. She says it’s not unusual for rare side effects to turn up when a drug transitions from clinical trials to widespread use, as the number of patients receiving it goes from the tens of thousands to the millions.

Brown says the F-D-A will have an advantage in considering the vaccine that it didn’t have when it decided whether to approve the previous vaccines: it has data not just from trials, but from the countries that have already approved it.

I-U is continuing to check in with its test subjects weekly for any sign of either side effects or COVID symptoms.