Democratic presidential nominee Hillary Clinton is recovering from pneumonia, according to her campaign, but the mysterious virus that they say caused her to collapse in New York City Sunday has made several staffers sick, according to a report from People Magazine.

“Everyone’s been sick,” a campaign source told People, describing “a debilitating bug” that was sickening at least six people including campaign manager Robby Mook.

The source cited a top adviser who had to go to the emergency room, after passing out from “severe dehydration.”

According to ABC News reporter Liz Kreutz, a Clinton aide confirmed the report, saying, “Yes, folks in our office have been sick.”