While we share many of the concerns voiced about the Star’s portrayal of the safety of HPV vaccination, we wish to emphasize the importance of investigative journalism in protecting Canadians from drug-related harm.

Most new drugs are approved after being studied in a few hundred or perhaps a few thousand study participants. These same drugs may then be prescribed to hundreds of thousands or even millions of patients. Sometimes safety concerns only come to light after a drug has enjoyed this kind of widespread use. When a problem with a drug is suspected, anyone can submit a report describing the issue to a regulator such as Health Canada.

The spontaneous reporting that springs from first-hand observation can be important, as illustrated by the notorious case of thalidomide. That thalidomide might cause birth defects was first proposed in a 15-line letter to the editor of The Lancet.

This report was nothing more than an obstetrician’s observation that some babies born with unusual malformations had been exposed to thalidomide in the womb. Aware that this could reflect coincidence but might also herald a serious threat to public health, the doctor concluded his letter with a question: “Have any of your readers seen similar abnormalities in babies delivered of women who have taken this drug during pregnancy?” Similar reports from others would later confirm that thalidomide was highly toxic to the developing fetus.

In recent decades, drugs used by tens of millions have been removed from the market because of concerns not appreciated at the time of approval. Indeed, the recently passed Protecting Canadians from Unsafe Drugs Act is often referred to as Vanessa’s Law, in memory of a young woman who died suddenly while taking cisapride, a drug widely perceived as “safe” but eventually pulled from the market after it was shown to trigger fatal heart rhythms.

In many instances, the first inkling of a problem with a new drug comes from spontaneous reports. It is likely that doctors are prescribing drugs today that are destined to be removed from the market once serious adverse effects are better appreciated. The sooner we know about these harms, the better.

Unfortunately, most adverse drug effects are never reported. The lack of an effective system for tracking the harms of treatments is a widely recognized failure of the health-care systems in Canada, the United States and elsewhere. Even clear patterns in reported adverse effects may not result in action because of the ways in which the data are stored and used.

Conversely, many reported adverse effects do not actually represent drug-related problems at all. Key information required to make that determination is often missing in reports submitted to Health Canada, and sometimes the information provided is biased by the beliefs of the individual filing the report.

For example, when a young person dies shortly after receiving a drug or vaccine, a family member may file a report indicating a causal connection, even when the link is tenuous or non-existent. Although such reports can create the illusion of harm, we believe there is merit in a culture that encourages rather than suppresses the reporting of suspected drug-related harms by the public and health-care professionals. Making sense of these reports is primarily the responsibility of Health Canada.

Investigative journalism can help uncover adverse drug reactions that might otherwise go unnoticed. The Star has conducted important investigations of this sort, raising awareness about serious concerns regarding the safety of stimulants for childhood attention deficit-hyperactivity disorder (ADHD), the overuse of antipsychotics in nursing homes, the dangers of drugs prescribed for unapproved indications and the disgraceful culture of secrecy at Health Canada.

We applaud the Star for those stories and believe that media coverage of legitimate adverse events can foster a culture of cautious reflection. Stories such as these encourage others to file reports and contribute to public safety, particularly when they expose dangerous patterns of medication use, corporate malfeasance or the ways in which regulators like Health Canada fail to protect public safety.

Nav Persaud is a family physician and lecturer at the University of Toronto. @navpersaud. David Juurlink is professor and Head of the Division of Clinical Pharmacology at the University of Toronto. @davidjuurlink