Some 140 cancer patients at two healthcare facilities in Seattle have been advised to seek testing for tuberculosis after a healthcare worker with latent tuberculosis infection developed active disease that went undiagnosed for some time.
The University of Washington Medical Center and the Seattle Cancer Care Alliance announced that an oncology worker with TB cared for the patients from May to July 2016. In addition, 47 healthcare workers were exposed and all have thus far tested negative for TB, which is not thought to be a drug-resistant strain.
The worker, who was not identified by name or gender, acquired TB five years ago from a patient, but had been successfully treated with isoniazid (INH), Steven Pergam, MD, director of infection control at Cancer Care, said at a recent press conference.
“There are a lot of healthcare workers that have latent TB and it is really important to understand that latent TB is not infectious,” he said. “Cases where [a healthcare worker] with latent disease goes on to develop active TB are exceedingly rare.”
The cancer patients may be immune compromised due to chemotherapy and other treatments, making it more likely for TB to progress if the patients become infected.
“Though they may not be more likely to acquire TB, the difference is that once they acquire it, they are more likely to develop active disease in a faster time frame than a normal person would with an adequate immune system,” Pergam said.
An immunocompetent person may manifest TB symptoms after exposure within the first two years, but cancer patients may develop active disease in a matter of weeks and months. The patients treated by the infected worker were contacted via letter offering free testing, and a hotline has been set up to field questions from the public. They will be tested initially and then again in two to three months.
“What made this challenging is that this [healthcare worker] has a health condition that led to a cough,” Pergam said. “They went to see a primary care doctor and were evaluated appropriately and received treatment for that.”
However, at some point the cough raised suspicions about TB and the worker was correctly diagnosed.
“TB can be difficult to sort out in its early phases,” he said. “Oftentimes it can be very subtle, particularly in a situation where someone has another condition that leads to a cough.”
Officials at both facilities said all protocols were followed, but will review the case to see if there were opportunities for earlier intervention. The local media at the Seattle press conference questioned why a healthcare worker with latent TB would be treating cancer patients.
“Healthcare workers that have latent TB don’t have active disease and are not infectious to anyone, so there really is no risk for them to work with cancer patients or any other immune compromised patients,” Pergam said. “We continue to screen them on a regular basis for the development of symptoms.”
The healthcare worker is being treated with INH and should be able to return to work in less than six months.
“I think it is really important that we don’t forget the healthcare worker in this and the challenges they have been through,” he said.
To further complicate the case, a close community contact of the worker tested positive for latent TB, which may have been from recent transmission or from a history of travel to areas where TB is common.