By Talal Ansari


A mass-vaccination site in Colorado was closed Wednesday after some people experienced adverse effects after being given a shot of the Johnson & Johnson Covid-19 vaccine.

A total of 11 patients were affected, according to Centura Health, one of the largest healthcare networks in the region, which runs the site along with the state of Colorado.

"Medical staff on site determined two individuals required additional observation and out of an abundance of caution, they were transported to a nearby hospital," Centura Health said in a statement.

It is unclear whether the adverse reactions were related to the vaccine.

Johnson & Johnson didn't immediately comment. The Colorado Department of Public Health and Environment didn't immediately respond to a request for comment.

The vaccination site at Dick's Sporting Goods Park, a stadium in Commerce City, just outside of Denver, was closed for the remainder of the day and existing appointments were rescheduled. The site is normally closed from Thursday to Saturday. Normal operations will resume on Sunday, a Centura Health spokesperson said.

More than 1,700 individuals had received vaccinations Wednesday, Centura Health said. The patients who experienced adverse reactions accounted for 0.62% of those vaccinated, it said.

Federal health regulators authorized]( Johnson & Johnson's [one-shot vaccine ( in late February, saying it was safe and effective. It is one of three vaccines authorized for use in the U.S., along with those from Pfizer and partner BioNTech, and Moderna.

Early safety monitoring of Covid-19 vaccines has found rare reports ( of severe allergic reactions after vaccination, according to the Centers for Disease Control and Prevention.

The Food and Drug Administration says people who are allergic to the ingredients of a vaccine shouldn't take it. The vaccines from Pfizer and Moderna contain, among other ingredients, the genetic material RNA and a substance called polyethylene glycol, which has been associated with rare allergic reactions. The J&J vaccine contains an adenovirus, a virus that can cause the common cold, which is rendered harmless; polysorbate and other ingredients.


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April 08, 2021 13:50 ET (17:50 GMT)

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