The hospital closed its operating rooms twice, first in May and again this month after discovering the mold Aspergillus in the air. One patient died and six more fell ill with the first mold outbreak.
But these seven patients were not the first to develop the infection. Jeff Sperring, the CEO, in a statement on Tuesday. Between 2001 and 2014, seven Seattle Children developed the same Aspergillus infection, and five of them died, Sperring said.
"At the time, we believed most of these were isolated infections," he said. "However, we believe these infections were probably caused by the ventilation systems operating our operating theaters."
During the temporary closure, the hospital plans to install new filtration systems in contaminated operating and service rooms to remove nearly 100% of the airborne particles that filter them.
Sperring said Seattle Children's will also examine his culture and leadership to examine how mold infections have remained uncontrolled for many years.
In the meantime, operations were moved to nearby partner hospitals until the contaminated areas were reopened in late January, he said.
Mold infections are more dangerous for already ill people.
Mold spores are present everywhere and only a few can cause serious infections. In people with weakened immune systems or lung disease, mold infections are a dangerous risk, according to the Centers for Disease Control and Prevention.
Aspergillus mold rarely suffers from healthy people. But its symptoms reflect those of other respiratory diseases – fever, hemoptysis, shortness of breath – and that's part of what makes it so dangerous for sick patients. It may go undetected before the infection spreads from the lungs to other parts of the body, according to the CDC.
Mold infections were associated with at least six deaths in three hospitals in Pittsburgh between 2014 and 2017. The hospital's laundry was the likely source of the longtime outbreak.
But these infections have been linked to Mucor, a mold that can cause a rare but serious infection that usually occurs outdoors, Pennsylvania health officials reported in 2016. Like Aspergillus, it is more dangerous for people with weakened immune systems, so the CDC.