Officials did not disclose the types of reactions suffered by less than 1 percent of the more than 1,700 people given shots at Dick's Sporting Goods Park in Commerce City, the Denver Gazette reported.
The vaccination effort was being sponsored by the state and Centura Health. More than 600 people with appointments Wednesday were unable to receive their vaccinations after the early closure.
"We followed our protocols and in an abundance of caution, made the decision — in partnership with the state — to pause operations for the remainder of the day," Centura Health officials said in the statement obtained by the newspaper.
People with appointments who were turned away will be rescheduled to receive their shots at a different site on Sunday.