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Minor breach, major problem: Toronto medical workers find SARS unforgiving’
CDC sends team of investigators to Canada
Despite use of full-barrier precautions, Canadian health care workers treating severe acute respiratory syndrome (SARS) patients for prolonged periods became infected with the emerging virus after minor lapses in infection control, a Toronto epidemiologist tells Hospital Infection Control.
"This virus, particularly in certain settings, appears to be relatively unforgiving," says Andrew Simor, MD, infectious disease consultant at Sunnybrook and Women’s College Health Sciences Centre at the University of Toronto. "If you end up being exposed to someone who is critically ill and producing large inoculum of virus — and you have a minor breach [in infection control] — that’s when it appears transmission most likely occurs."
The infection control community was shocked when reports began coming in that 15 to 20 Toronto health care workers occupationally acquired SARS even after donning gowns, gloves, goggles, and N-95 respirators. The Centers for Disease Control and Prevention (CDC) dispatched a team of investigators to Toronto that included Julie Gerberding, MD, MPH, CDC director, and experts in health care epidemiology, occupational safety, and environmental engineering.
"The CDC team in Toronto [went] there at the invitation of Health Canada to help assess with, really, a fresh set of eyes,’" she says. "After very good infection control precautions were implemented, there were still a few cases of transmission of SARS to health care personnel. When you are doing everything right, you have to back up a little bit and say, Is there absolutely anything that we’re overlooking?’ And sometimes getting a fresh set of consultants in can really see things that the people, front and center, miss."
CDC investigators spent close to a week in Toronto, investigating cases and designing a very detailed worker questionnaire to try to determine how transmission occurred, Simor says.
Though the investigation continues, the emerging theory in many of the cases is that minor breaches reaped major consequences, he says.
"In cases where there is no particular [exposure] incident that comes to mind, we know that there were minor breaks by individuals who had been working with SARS patients for weeks at a time," Simor says. "They were getting fatigued and recognized that there were momentary lapses where they forgot to put on their goggles, forgot to change their mask, or whatever. That may have contributed."
The cases all occurred after March 28, 2003, when strict standards were set for all Toronto hospitals treating SARS patients. The standards include placing all SARS patients in private, negative-pressure rooms that have restricted access. Anyone entering the room wears gloves, gowns, N-95 respirators, and goggles or some other kind of eye protection.
"Despite those precautions we had transmission occur in a number of Toronto hospitals, including our own," he says. "This has happened in about five or six hospitals in the city."
Confused, combative, and infectious
Some of the cases of SARS transmission to workers are being traced to high-risk procedures such as intubation, which can create aerosolization of respiratory secretions from the infected patient. Combine such procedures with a recalcitrant, SARS superspreader and you have a worse-case scenario for transmission.
"In particular, in our hospital, there was a very difficult intubation with a hypoxic patient who was confused and combative throughout the procedure," Simor says. "We believe he was one of these hypershedders."
The patient initially was given BYPAP ventilation, an aerosol-generating procedure that is commonly done in intensive care units to try to prevent or delay the requirement for intubation.
"He was on BYPAP for a number of hours, and huge amounts of fluid from respiratory secretions were discharged into the environment and aerosol-ized," Simor says.
"Also, during the [intubation] procedure, someone’s mask slipped. So there were a number of things around this particular difficult intubation that led to the exposures and subsequent infection of health care workers," he says.
After that, the hospital adopted a policy forbidding nonemergency aerosol-generating procedures on SARS patients.
"We are recommending that if they do require intubation, then only the most experienced personnel do it," he says. "The patient [must] be sedated, and if need be paralyzed, in order to make it a quick smooth intubation."
The cases of occupational transmission have heightened fears, but all in all, health care workers in Toronto have been nothing short of courageous in dealing with the SARS situation, he adds.
"The level of anxiety of all of the health care workers is heightened as a result of this experience," he says. "And we have been dealing with it in Toronto for weeks so there is a certain amount of fatigue as well. But with all that, I have been impressed with the heroic efforts that all of our health care workers have made under this difficult situation. They continue to go above and beyond the call of duty to provide excellent care for our patients despite personal risk."
Lessons from Canada
The seriousness with which Toronto has taken its situation — quarantining more than 10,000 people during an outbreak that appeared to be subsiding as this issue went to press — was impressive to the CDC visitors.
"I learned the steps that were taken in Canada and in Ontario to contain the epidemic in hospitals and in the community," Gerberding says. "We haven’t had to move outside of our regular infection control precautions so far, but if we needed to, if we had a situation where there was a leak in our containment, we need to be prepared to take additional steps. We would much rather have the plans in place to initiate those steps now, learning lessons from everyone else who’s already had to invent those processes on the fly."
In that regard, the CDC recently held a meeting to begin gearing up states and public health partners to develop plans for a quarantining hospitals and residential facilities, including apartment complexes.
"One of the specific lessons I learned in Canada was that if you’re going to take a step like that — if it becomes necessary — you have to be bold and you have to do it quickly," Gerberding adds.
"You have to be aggressive in the implementation. There is not a lot of time for a lot of committee meetings or discussion and debate. You’ve got to get the job done. And so we have brought back from Canada that experience and the protocols and plans that they developed there in a hurry. We intend to vet those with the stakeholders in the state, and local and hospital community to make sure that we’re ready," she says.
But while planning for the worst, she acknowledges the best from the U.S. perspective.
"The containment in the United States has been successful. We still do not have a complete understanding of why, so far at least, we’ve not had spread into the community, but I do want to specifically acknowledge the tremendous contribution that our health officials have been making at the local and state level, " she says. People have stepped up to the plate, have developed locally relevant infection control guidelines, have worked aggressively to identify and respond to patients, and I think a large part of our success so far is due to the incredible efforts that these individuals are making. I salute them."
Indeed, that story is being played out all over the country by individual ICPs such as Noell McKernan, RN, CIC, infection control practitioner at Buffalo (NY) General Hospital.
McKernan may be a little more vigilant than some, since her hospital sits only a routine commute away from Toronto.
"But we don’t just automatically [suspect people] coming from Toronto, because there are hundreds of people who go back and forth from Toronto on a daily basis," she says. "[The question] has to be, have they been in actual contact with a patient who has had SARS?"
Personnel throughout the hospital — including in admissions, security, emergency room, and outpatient clinics — have been instructed regarding SARS, the latest CDC case definition, and measures to take for suspect cases.
"If someone comes in who is symptomatic, until we have questioned them as to where they have traveled and who they have been in contact with, we give them a mask and tissues until we have ruled them out," McKernan says.
Patients admitted with an atypical pneumonia may be triaged into SARS rule-out, meaning they will remain in isolation in a negative-pressure room until the clinical call is made.
"We have had several come in that are rule-out cases — mainly though the emergency room," she says. "We have not had a case that has proven to be SARS."
Are we dealing with the same strain?
The striking contrast between Toronto and the United States, where SARS cases have been stamped out as they appeared, has led some to suggest that there may be more virulent strains of the virus in some regions.
"Our experience certainly mirrors that of Hong Kong and Singapore in terms of the ease and pattern of spread and also the clinical course of mortality," Simor says.
"Our experience seems to be similar to that in Asia, and it does seem to be a little different from the American experience at least to this point in time. It is difficult to understand why that should be true," he points out. "One explanation is perhaps different stains of the virus; alternatively, it might be because different patient populations have become infected. Clearly, the load of organisms plays a role here. The concept of the heavy shedder appears to be borne out by our observations, and that may also be a factor."
Indeed, the United States and, for that matter, any other relatively unaffected country may be only one undetected superspreader away from moving suddenly from calm to storm.
"We have been fortunate in that a particularly infectious patient has not slipped through the cracks or had a long period of time to be exposed to others in the home or in the health care setting," Gerberding says.
"We need to appreciate and acknowledge that we are fortunate and, at the same time, that [this] is not a permanent state. As we saw in Taiwan, just a single highly infectious individual who is not picked up through the public health system or the clinical system can set off a cascade of transmission with very serious consequences in the community," she adds.
Thus vigilance is the watchword in the United States, even as Toronto seems to be breaking the SARS stranglehold. But the fire burns on in China, heightening concerns that if SARS reaches Third-World nations in regions such as Africa it will gain a global foothold that will be impossible to eradicate.
"That is an enormous concern," Simor says. "In those settings, they have even fewer resources to deal with it as a public health calamity. The potential for widespread dissemination is very real."