Approximately 450 patients were exposed to HIV, hepatitis B or hepatitis C over a two-year period at Salem Hospital in Massachusetts.
These people would have been exposed to these diseases during an endoscopy, CNN reports.
All affected patients were contacted and tested for hepatitis B, hepatitis C and HIV free of charge.
“To date, there is no evidence that anyone has become infected as a result of this incident,” the hospital said in a statement.
The U.S. Department of Health and Human Services says it is working with the hospital to “manage the situation,” adding that the risk of infection following this exposure is “relatively low.”
This is not the first time such mass exposure to serious illnesses has occurred in the United States.
Specifically, in 2018, more than 3,000 patients at a surgical center in Saddle Brook, New Jersey were exposed to multiple pathogens including hepatitis B and C and HIV.
An investigation by the New Jersey Department of Health found that HealthPlus Surgery Center staff did not closely follow procedures, leading to this incident.