Tuberculosis Is Treatable. So Why Is It Still An Epidemic?

Since the COVID-19 pandemic emerged in 2020, it has been the center of attention in public health and politics. However, an ancient infectious disease continues to cause almost as many deaths as COVID-19.

According to the World Health Organization (WHO), a total of 1.5 million people died from tuberculosis (TB) worldwide in 2020. As a reference point, the official COVID-19 death toll reported by the WHO in 2020 was 1.8 million (although the true death toll could be closer to three million).¹ ²

Before COVID-19, TB was one of the deadliest infectious diseases.³

But if TB is such a major public health issue, why don’t health authorities issue daily updates about infection rates? And why don’t journalists discuss the death toll on their evening news bulletins?

Perhaps it’s because 95% of TB cases and deaths occur in developing nations. In 2020, two in three new cases were found in eight countries: India, China, Indonesia, the Philippines, Pakistan, Nigeria, Bangladesh, and South Africa.

Socioeconomic factors, including poverty and overcrowding, are the main drivers for TB spreading in developing nations. Malnutrition and crowded housing (which hastens the spread of TB) are also common. Cases are rarely picked up as TB can present late or may not be treated appropriately through weakened public health systems.⁴

But even though the burden of TB is low in developed nations, it still remains a global concern, given its transmissibility and growing drug resistance.

In the US, for example, there were 7,163 reported cases of TB in 2020. The current yearly rate of TB decline is too slow to reach the TB elimination goal (one case per million people) within this century. Furthermore, the gains we made over the past decade to reduce TB’s spread have been partially reversed because of COVID-19 complications.⁵ ⁶

If treatment options do not keep up with the modern challenges of TB, we could be facing a resurgence of the disease. In this article, we uncover all you need to know about the TB pandemic and why it should still be a concern.

What is tuberculosis?

TB is a disease caused by a bacteria called Mycobacterium tuberculosis. This bacteria most commonly infects the lungs and destroys tissue. It can also attack other parts of the body, including the kidneys, spine, and brain.

Droplets can spread between people when a person with TB coughs or sneezes. This causes the bacteria to linger in the air. When a nearby person inhales these droplets, they can become infected. Therefore, healthcare providers and close contacts need to adhere to proper isolation measures and mask-wearing.⁷

TB symptoms include coughing for over three weeks, coughing up blood, chest pain, weight loss, fatigue, and fever. The infection can be fatal when left untreated.⁸

The good news is that TB is now a highly curable disease when detected and treated early.

Active and inactive tuberculosis

There are two forms of TB: active and inactive (or latent).⁹

People with active tuberculosis experience symptoms and can spread the disease to others.

Latent tuberculosis is when a person is infected with the bacterium but does not have any symptoms and is not infectious. The bacteria can lay dormant in the person’s body for a whole lifetime without issue in many cases.

However, if the bacteria become active (reactivated) because of a weakened immune system, the person may develop TB disease. People with latent TB usually get a positive result in the TB skin or blood test.¹⁰

Who is the most vulnerable to tuberculosis?

Tuberculosis is most commonly seen in adults but can affect people across all age groups.

The disease is most likely to spread in developing countries, as poverty, overcrowding, and poor healthcare make it difficult to control. However, other risk factors can also increase your chances of developing TB.

It’s particularly dangerous if your immune system is weakened — for example, if you are HIV-positive. This is because your body is less capable of fighting off infection.

People living with HIV are approximately 18 times more likely to be infected with TB compared to those without HIV. TB claims the lives of one in four people with HIV. The two conditions are also syndemic, meaning they interact with one another to increase their progress.¹¹

Smoking and drinking alcohol have also been linked to an increased risk of developing TB and poorer response to treatment. This is because of how both behaviors affect the immune system.

One study found the risk of death from TB among smokers without a previous TB infection is nine times greater than among those who have never smoked before.¹²

A cohort analysis in Singapore found participants who drank two or more alcoholic drinks per day and smoked were at greater risk of TB infection compared to those who neither smoked nor drank.¹³

The history of tuberculosis

We know a lot about tuberculosis because the disease’s history is long and complicated.

Experts believe TB has been around for at least 70,000 years. Early references to the disease date back to ancient Egypt. It was even called “Captain of All These Men of Death” in the 18th century because around one in four deaths was attributed to the disease in Europe and North America.¹⁴

The modern era of tuberculosis began in 1882 when a French doctor named Robert Koch discovered the bacterium that causes the disease. This discovery led to the development of effective treatments and vaccines, and TB rates began to decline in developed countries.

Tuberculosis is highly curable

About 85% of people infected with TB can be cured with treatment. More than 60 million TB deaths have been avoided since 2020 because of treatment, which also helped reduce the disease’s spread.¹⁵

Isoniazid (an antibiotic) with rifampin, pyrazinamide, and ethambutol is currently the most common multidrug TB treatment. You would need to take a full prolonged course of these medications, usually over 6–12 months. Symptoms usually start to improve a few weeks after starting treatment, as TB takes a long time to cure compared to other infections.

However, you must continue taking the medication for the course’s complete duration. Not doing this could make you vulnerable to reinfection while also creating wider drug resistance at a population level.¹⁶

The modern challenges we face with tuberculosis

Although tuberculosis has been around for many centuries, we are now facing new challenges.

Tuberculosis has become more resistant to drugs

TB strains becoming unresponsive to drug treatment is one of the biggest challenges we face with the disease today.

Multidrug-resistant tuberculosis (MDR-TB) is now the most common strain. It’s resistant to treatment with at least two of the most effective first-line drugs: isoniazid and rifampicin.⁹

Extensively drug-resistant tuberculosis (XDR-TB) is a strain that’s resistant to the four most-used TB drugs.

TB drug resistance originally emerged as a result of improper use of TB drugs. When the bacteria isn’t fully eradicated from the body due to improper drug use, new strains emerge that are more resistant to treatment.

Improper drug use may have come about due to individuals not taking their prescribed dosage or stopping treatment before they completed the full course. Poorly trained healthcare providers who prescribed the wrong dosage or treatment length may also have contributed.¹⁷

MDR-TB is a public health concern because it is more difficult and expensive to treat than drug-sensitive TB. It can lead to death in up to half of cases. The Centers for Disease Control and Prevention (CDC) estimates about 500,000 people get infected with MDR-TB globally each year, which results in approximately 200,000 deaths.¹⁸

MDR-TB medication requires up to two years of treatment, while non-resistant TB only requires 6–12 months of treatment. A full course of treatment requires the person to take up to 15,000 pills compared to fewer than 750 for regular TB.

The drugs used are also more toxic and cause long-term side effects. These include adverse effects on neurological and kidney function.

Being infected with drug-resistant TB may also result in surgery to remove the infected tissue.¹⁹ ²⁰

In 2015, it was estimated that MDR-TB would cause over 75 million deaths over the next 35 years. The global economic cost is estimated to be $16.7 trillion.²¹

Fortunately, researchers made breakthroughs in the fight against MDR-TB in 2019. The US Food & Drug Administration (FDA) approved one of three new drugs developed by the TB Alliance. This drug shortens the MDR-TB treatment duration from two years to six months.²² ²³

The new BPaL regimen consists of three medications: bedaquiline, pretomanid, and linezolid.

The trial was conducted across three areas in South Africa. It included 109 participants with XDR-TB and MDR-TB. 95 of the first 107 patients had positive outcomes after six months of undergoing the BPaL regimen. This equates to a success rate of around 90%.

The 100-year-old tuberculosis vaccine needs an update

A TB vaccine has helped combat the disease over the last century, but its efficacy is limited, and a better vaccine is needed.

2021 marked the 100th anniversary of the discovery of the Bacille Calmette-Guérin (BCG) vaccine. It is a live, attenuated vaccine used to protect against tuberculosis. The vaccine was first developed in 1921 and has been used for over a century.

However, recent studies have called the efficacy of the vaccine into question. Experts claim it only protects young children from very severe forms of TB and that it stops being effective once they reach adolescence.

As a result, the BCG vaccine is most commonly administered in nations or communities with a high number of TB cases. Vaccine policies in low-burden countries vary greatly.

Despite its long history, little is known about why the BCG’s effectiveness wanes over time. This is why many leaders in the public health and research communities have called for more international collaboration and investment in developing a new, more effective vaccine.²⁴ ²⁵ ²⁶

The COVID-19 pandemic has caused an increase in tuberculosis cases

Our latest challenge with TB comes from another disease — COVID-19. Health resources and services have been diverted over the past few years, leaving TB efforts by the wayside.

The WHO reports a significant decline in the number of people being diagnosed and treated for TB. It estimates that reported cases dropped by 25–30% across three high-burden countries: India, Indonesia, and the Philippines.

Other experts have reported that 2020 was the first year with a year-over-year increase in TB deaths since 2005.

As the impact of COVID-19 on TB is expected to be long-lasting, the WHO has appealed to countries to ensure TB services remain accessible. This includes taking steps to increase remote support and consultations by focusing on at-home treatments and ensuring patients have enough drugs between medical consultations.⁶ ¹⁵

Poverty remains a primary driver of tuberculosis

While evolving TB strains and resource competition from other pandemics present new challenges in the fight against TB, poverty remains a strong driver of the TB pandemic.

The WHO advises that US$13 billion is needed each year to achieve global TB targets for prevention, diagnosis, and access to treatment. These funding targets are not being met. In 2020, there was a US$7.7 funding gap.

Global TB spending fell by 8.7% between 2019 and 2020. The majority of this funding (81%) was raised locally in countries with the highest burden of disease (including Brazil, Russia, India, China, and South Africa). International donors have invested US$0.9 billion yearly over the past decade.

Despite these efforts, more money is needed. The WHO is urgently asking nations to provide more domestic and international funding to end the TB pandemic.¹ ²²

The lowdown

As time passes, new challenges will emerge in the fight against TB. But the core solutions remain the same. These include continuing to fund vaccine and treatment research while working to improve access to healthcare in developing countries.

Health authorities have the tools to execute these solutions, but more coordinated international efforts are needed to bring them to fruition. Only by taking these steps can we hope to finally bring an end to this ancient, deadly disease.

Sources:

1. Fact sheets: Tuberculosis | World Health Organization

2. The true death toll of COVID-19: Estimating global excess mortality | World Health Organization

3. Tuberculosis remains one of the deadliest infectious diseases worldwide, warns new report (2022)

4. Tuberculosis is the oldest pandemic, and poverty makes it continue (2022)

5. TB in the United States: A snapshot | Centers for Disease Control and Prevention (CDC)

6. COVID-19’s devastating effect on tuberculosis care — A path to recovery (2022)

7. How TB spreads | Centers for Disease Control and Prevention (CDC)

8. Signs & symptoms | Centers for Disease Control and Prevention (CDC)

9. Global pandemic | TB Alliance

10. Latent TB infection and TB disease | Centers for Disease Control and Prevention (CDC)

11. HIV and tuberculosis: A deadly human syndemic (2011)

12. Risk factors for tuberculosis: diabetes, smoking, alcohol use, and the use of other drugs (2018)

13. Alcohol drinking and cigarette smoking in relation to risk of active tuberculosis: prospective cohort study (2017)

14. The history of tuberculosis: from the first historical records to the isolation of Koch’s bacillus (2017)

15. WHO: Global TB progress at risk (2020)

16. Treating and managing tuberculosis | American Lung Association

17. Drug-resistant TB | Centers for Disease Control and Prevention (CDC)

18. The urgent threat of TB drug resistance (2016)

19. The medical and surgical treatment of drug-resistant tuberculosis (2014)

20. Side effects associated with the treatment of multidrug-resistant tuberculosis at a tuberculosis referral hospital in South Korea (2017)

21. Drug-resistant TB threatens to kill 75 million people by 2050, cost $16.7 trillion (2015)

22. FDA approves new treatment for highly drug-resistant forms of tuberculosis (2019)

23. Bedaquiline, pretomanid and linezolid for treatment of extensively drug resistant, intolerant or non-responsive multidrug resistant pulmonary tuberculosis (2020)

24. Investing in new TB vaccines: It’s time to end the century-long wait! (2021)

25. Tuberculosis, the forgotten pandemic relying on a 100-year-old vaccine (2021)

26. Tuberculosis kills as many people each year as COVID-19. It’s time we found a better vaccine (2021)

27. WHO: Increased funding can end global TB epidemic (2022)

Dawn Teh is a health writer and former psychologist who enjoys exploring topics about the mind, body, and understanding what helps humans thrive.