When a cluster of patients develops the same serious infection after treatment by the same physician at the same clinic, the medical evidence is sometimes able to point to a specific Infection Prevention and Control failure as the cause. More often, it cannot. The pathogens are everywhere, the procedures involve sterile technique that is hard to reconstruct after the fact, and the chain of transmission is invisible by the time the cluster is detected.
The Court of Appeal’s decision in Levac v James, 2023 ONCA 73, provides important guidance on how plaintiffs can prove causation in those cases. The court affirmed Ontario’s first medical malpractice class action common issues trial, in which the trial judge used powerful circumstantial and epidemiological evidence to draw a rebuttable, class-wide inference that a physician’s breach of the standard of care for IPAC caused infections in his patients. No single procedural deficiency could be scientifically demonstrated to have caused the spread. The statistics did the work.
The facts
Between roughly 2012 and 2014, an outbreak of Staphylococcus aureus and other serious infections was identified among patients of Dr. Stephen James, an anesthesiologist who administered epidural injections for pain management at the Rothbart Centre for Pain Care in Toronto. Some patients developed meningitis. Some developed abscesses in or around the spinal canal. Others developed deep tissue infections.
Toronto Public Health investigated and concluded that the outbreak was caused by inadequate IPAC during the injection procedures. Two pieces of evidence pointed firmly at Dr. James.
First, the rate of infection associated with his injection practice was many times higher than the published rate for the procedure when proper IPAC is in place. Second, Dr. James himself was found to be colonized with a rare strain of Staph aureus called CC59. That same strain was found in six of his infected patients. The investigators called these the Genetically Linked Patients.
Anne Levac, one of the infected patients, brought a class action in 2014 on behalf of approximately twenty former patients of the Rothbart Centre.
The trial decision
After a five-week common issues trial, the trial judge found Dr. James liable to the class on every common issue: duty of care, standard of care and its breach, causation, fiduciary duty, limitation period, and entitlement to punitive damages.
For the Genetically Linked Patients, causation was proved directly. The genetic match between Dr. James’s CC59 strain and the bacteria infecting those patients made it more likely than not that he was the source.
For the remaining class members, direct genetic proof was not available. But the trial judge drew a rebuttable inference of causation from circumstantial evidence, in particular the epidemiological evidence showing that Dr. James’s patients faced a risk of infection that was either 49 or 69 times higher than the baseline risk for properly performed epidural injections. Against the 2.0 risk ratio benchmark that earlier Ontario authority (Andersen v St. Jude Medical, Inc., 2012 ONSC 3660) had treated as a meaningful threshold for inferring causation, the Levac numbers were not close. The trial judge described them as “overwhelming.”
From that gap, the judge inferred that for any class member who developed an infection following an injection by Dr. James, the infection was more likely than not caused by his negligent IPAC. The inference was rebuttable. At the individual issues phase, Dr. James can still try to show, for any specific class member, that their infection arose from some other source. But the burden has shifted. The plaintiffs do not have to prove causation from scratch in each individual case.
The appeal
Dr. James appealed essentially every liability finding. His most pointed argument was that the trial judge had effectively revived the common law doctrine of res ipsa loquitur, retired by the Supreme Court of Canada in Fontaine v British Columbia (Official Administrator), 1998, and used the class action framework to relieve the plaintiff of her burden of proof.
The Court of Appeal unanimously rejected those arguments and dismissed the appeal. The trial judge had not revived res ipsa loquitur. He had drawn an inference from circumstantial evidence, which is permitted, and had been explicit that the inference was rebuttable. The class proceedings framework had not been used as a shortcut. The common issues had been answered on a common evidentiary record, and the individual issues, including individual causation defences, remained for later determination.
The Court of Appeal’s reasons clarify the conditions under which epidemiological evidence can support an inference of causation: a proven breach of the standard of care, a proven injury, powerful statistical evidence linking the two, and the absence of a plausible alternative non-negligent cause.
Why this case matters
For plaintiffs and their counsel. Levac is significant precedent for cases in which direct evidence of the causal mechanism is impossible to obtain. Infection outbreaks are the obvious example, but the same logic can apply to medication errors at scale, defective medical device claims, pharmaceutical mass torts, and any cluster injury where the harm is observable but the exact transmission mechanism is not. Where the statistical pattern is striking enough, a rebuttable inference of causation is available. Class certification of common issues including causation is also confirmed as a viable path.
For physicians, clinics, and their insurers. The decision underscores that the absence of a demonstrable smoking-gun deficiency is not, by itself, a defence. Where the rate of harm associated with a physician’s practice is dramatically out of step with the baseline, that gap is itself evidence. IPAC obligations are real, contemporaneous documentation of compliance matters, and infection control protocols at private clinics will be scrutinized as they would be in a hospital.
For patients. If you or a family member developed a serious infection after a procedure performed at a clinic or hospital, particularly if there were reports of other patients in the same period developing similar infections, Levac now exists as a route to compensation that did not look as well established before. Patients in those situations should be asking whether a public health investigation was conducted and whether anyone has commenced or is contemplating a class action.
For more on how medical malpractice cases are built and tried in Ontario, see Suing for Medical Malpractice in Ontario: What You Need to Know. For information specific to Hospital Negligence claims, see the relevant practice page.
Decision Date: February 2, 2023
Jurisdiction: Court of Appeal for Ontario
Citation: Levac v. James, 2023 ONCA 73 (CanLII)
