MADISON, WI (WKOW/WSIL) -- The COVID-19 vaccine trial underway at multiple locations, including University of Wisconsin Health, is on hold after one participant in the United Kingdom suffered a serious adverse reaction.
A spokesperson for the hospital confirmed to WSIL's sister station, WKOW in Madison, Wisconsin, the trial was put on hold Tuesday and would pause new enrollments in the study.
 reported that the vaccine developed by AstraZeneca and the University of Oxford was the one to cause the reaction. The report did not specify the severity or rarity of the reaction.
The vaccine study at UW Health was in the third and final phase of testing before going to the Food and Drug Administration for approval.
In response, nine pharmaceutical companies, including AstraZeneca, released a joint pledge to prioritize safety in their COVID-19 vaccines.
The pledge included four points:
- Always make the safety and well-being of vaccinated individuals our top priority.
- Continue to adhere to high scientific and ethical standards regarding the conduct of clinical trials and the rigor of manufacturing processes.
- Only submit for approval or emergency use authorization after demonstrating safety and efficacy through a Phase 3 clinical study that is designed and conducted to meet requirements of expert regulatory authorities such as FDA.
- Work to ensure a sufficient supply and range of vaccine options, including those suitable for global access.
"We believe this pledge will help ensure public confidence in the rigorous scientific and regulatory process by which COVID-19 vaccines are evaluated and may ultimately be approved," the companies wrote.
 that it became one of the first sites in the country to begin testing the vaccine. At the time, the hospital said it would recruit 1,600 people to participate in the trail.
Those who joined the study had a one-in-three chance of receiving a placebo instead of the trial vaccine.
