A mass vaccination site in Commerce City, Colo., suspended operations Wednesday after almost a dozen people reported adverse reactions after getting their COVID-19 shots.

At least 11 people who received a Johnson & Johnson injection at the city's Dick's Sporting Goods Park said they experienced nausea and dizziness minutes after their jabs.

Medical staff determined that two people needed additional observation and were taken to nearby hospitals for further aid. The nine others who became sick were given juice and water before being cleared to go home.

State health officials quickly reassured the public, saying there's no reason for further concern for other people who were vaccinated that same day. The decision to pause operations at the site was done out of an abundance of caution, city officials said.

"We know it can be alarming to hear about people getting transported to the hospital, and we want to reassure Coloradans that the CDC and public health are closely monitoring all the authorized vaccines continually," said Scott Bookman, COVID-19 incident commander at the Colorado Department of Public Health and Environment. "From what we know, today's side effects were consistent with what can be expected."

A spokesman for Centura Health, which is administering the vaccination site with the state of Colorado, said the number of people who fell ill amounted to less than 1% of the 1,700 patients receiving shots that day.

The site had administered the Johnson & Johnson vaccine before, and problems are rare. The federally run Vaccine Adverse Event Reporting System reports there have been 10 previously documented reactions at community vaccine sites.

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