March 24 is World Tuberculosis (TB) Day, which aims to raise the awareness about the devastating health, social and economic impacts of this infectious disease that primarily affects the lungs and spreads through the air when an infected person coughs or sneezes. Despite being preventable and treatable, TB remains a significant global health challenge.
UHN News sat down with Dr. Sarah Brode, Physician Lead, UHN's West Park Healthcare Centre TB Program and Medical Director of the Toronto Western Hospital TB Clinic, to discuss the status of TB both globally and in Canada.
How serious is tuberculosis (TB) to the patient and to society as a whole?
TB is treatable and it's usually curable. But it's a serious illness, and it has a very high mortality rate if it's not treated.
Worldwide, it's the leading cause of death from an infectious agent. COVID-19 had that distinction for a couple of years, and now TB has that distinction again. It kills more people than COVID. It kills more people than HIV. About 10 million people get TB worldwide every year, and over a million people die from TB. Before the advent of antibiotics, when TB was not treated, about 50 per cent of people with TB would die from TB.
TB tends to be lower in the public consciousness than other diseases affecting the respiratory system such as COVID-19 or respiratory syncytial virus (RSV). Is that because cases are falling?
No. TB rates in Canada have been rising and are at the highest level that they've been in the last 20 years. The latest data we have for the country is from 2023 when there were 2,217 new cases of TB. This translates to a rate of about 5.5 per 100,000 people.
TB rates in Canada are much lower than the rates of COVID-19 and RSV, so that could be partly why it's not as much in the public consciousness. But TB remains an issue in Canada and the rates are not falling.
What is fueling the increase?
The incidence of TB around the world has been going up since 2021. It's believed to be driven mainly by disruptions to TB programs because of the COVID-19 pandemic. A lot of public health efforts and resources that were usually used for TB went to COVID, including screening and treating TB infections.
As well, since people were concerned about contracting COVID in the hospital, there were more delayed TB diagnoses. This likely led to more transmission of TB, because people were sick with untreated, contagious TB for longer periods of time.
Are there different forms of TB and their treatment?
TB comes in two forms. First, there's "TB infection" or what we used to call latent TB infection. This is when the germ is in the patient's body, but it's being controlled by their immune system. It's not active, so people don't feel sick and they can't spread it to other people. But it's there.
In the future, the TB infection could become active. That is when people get sick with "TB disease," which is the second form. This is what most people think of when we say TB. It most commonly involves the lungs, but it can involve other organs. People with TB in the lungs can spread TB to other people and if it's not treated, they get sicker.
The treatments are different for TB infection and TB disease. TB infection is typically treated with a three-to-four-month regimen of one or two drugs. TB disease is treated with a four-drug regimen that's typically given for about six to nine months.
What specifically does UHN offer to treat TB?
UHN offers all of the guideline-recommended treatments for TB, both at Toronto Western Hospital and West Park Healthcare Centre. West Park has the only dedicated inpatient TB unit in the province, and the clinical team there has special expertise in treating drug resistant TB, so patients with drug-resistant TB are usually treated at West Park.
How serious is TB infection or the "sleeping TB?"
TB infection, or what we used to call "latent TB infection," is not contagious. It's estimated that about 25 per cent of the world's population has TB infection and only about 10 per cent of them will go on to get TB disease.
A big part of what we do in the TB clinics is identify people who have TB infection and also identify if they have risk factors for progression to TB disease. Then, we give them a preventive treatment to prevent it from happening.
What is the biggest challenge for you as a clinician and others treating TB?
There are two challenges. The first is access to essential TB medicines in Canada, which was highlighted in a recent report by Stop TB Canada. In order for a medication to have a license in Canada, the manufacturer has to submit an application. However, due to the small market for TB drugs in Canada, many TB drug manufacturers have no motivation to submit a license request.
For example, special pediatric TB medicines are dissolvable forms, which are more palatable for kids. But they are just not available in Canada. It's very hard to treat kids with TB: parents or care providers are crushing these pills that taste bad, and trying to get kids to them take them can affect adherence.
Another example relates to some of the newer second-line drugs that we use to treat drug-resistant TB. We can still access these medicines in Canada, but it requires extensive paperwork, and also often requires that the medications are shipped from other countries, which leads to delays in accessing the medicines when they are needed.
And, even the standard first-line TB medicines, which are licensed in Canada, are often undergoing drug shortages once every year or two.
The second challenge is limited health system capacity for TB in other parts of Canada, including smaller northern communities. Some of these areas lack the resources needed to effectively diagnose and treat TB, as well as screen and treat latent TB infection.
We have been fighting TB for more than 100 years. What has changed?
In the last few years, there's new recognition that we won't be able to eliminate TB without investing in screening and treating TB infection. It was thought 10 or 20 years ago that if we diagnose early and just do a better job of treating TB disease, we will eliminate TB. That is not going to happen.
Modeling studies show that even if you do better treating TB disease, you will never eliminate TB. You have to address TB infection. So there's a growing push to screen and treat people for TB infection (the sleeping form of TB).
Drug-resistant TB is also becoming a larger and persistent challenge that's not going away. Again, there was this perception that if we treated people properly and made sure they took their medicines, we would eliminate drug-resistant TB, and that's not the case.
With every new TB drug that is released, we start to see drug-resistant forms of TB developing a year or two later. Recognizing this problem, we need to keep developing new drugs and focus on creating new drug regimens to prevent drug resistance from happening.
On World TB Day, what does the average Canadian need to know about the disease?
It's important just to be aware that TB remains an issue in Canada. More than 2,000 people get sick with TB every year in Canada, and many more with TB infection are placed on preventive treatment.
It's an enormous issue worldwide. With funding in global health fluctuating, Canadians should advocate for improved TB care and access to TB medicines. Additionally, we need to step up investment in international TB aid, as global TB challenges can directly impact us.
