Tuberculosis: Why Haven’t We Eliminated TB Yet?

According to WHO, in 2021, just eight countries were responsible for more than two-thirds of global TB cases:

• India: 28%
• Indonesia: 9.2%
• China: 7.4%
• Philippines: 7%
• Pakistan: 5.8%
• Nigeria: 4.4%
• Bangladesh: 3.6%
• Democratic Republic of the Congo: 2.9%.
  

Image: Worldwide Tuberculosis (TB) cases 1956-2019. Copyright © GIDEON Informatics, Inc.

With so many people affected by TB each year, what are the global strategies to detect, treat, and prevent TB infections?

WHO intends to eliminate TB worldwide by 2030 through its End TB initiative. One key milestone is achieving an 80% drop in tuberculosis cases by 2030.

Unfortunately, progress has been stunted. From 2015-2022, TB cases were reduced by 8.7%—a far cry from the WHO End TB Strategy’s projection of 50% by 2025.

India’s plan to eliminate tuberculosis

India set ambitious goals to eliminate tuberculosis (TB) by 2025 with their TB National Strategic Plan (NSP) 2020 – 2025, despite having the highest number of TB cases and deaths. 

Having missed most of the key milestones along the way, India will most likely not eliminate TB by 2025 (WHO’s ‘Global TB Report 2023’). However, the country has improved how it detects and reports new cases. TB treatment coverage has also increased.

Indonesia’s plan to eliminate tuberculosis

According to WHO, Indonesia is not on track to eliminating TB by 2025, per the End TB Strategy and the Sustainable Development Goals.

WHO notes that TB in Indonesia is mainly due to undernutrition, smoking, diabetes, and HIV. 

China’s tuberculosis eradication efforts

China has made significant progress in reducing the number of tuberculosis (TB) cases. China had reduced the incidence of TB by 24% between 2010-2019 (WHO).

In 2019, China announced another plan to prevent and control TB. Its goal was to reduce the rate of people affected by TB to less than 55 in 100,000 and the mortality rate to less than 3 in 100,000 by 2022.

There are many roadblocks along the path to getting rid of TB worldwide. These include addressing drug-resistant strains, low awareness about the disease, funding, and engaging the private sector to help eliminate the disease. 

Overcoming these obstacles is crucial for a TB-free future. Let’s look at the top issues preventing TB from becoming a thing of the past.  

1. Multidrug-resistant tuberculosis (MDR-TB) and Extensively drug-resistant TB (XDR TB) on the rise

Multidrug-resistant tuberculosis (MDR TB)

Multidrug-resistant tuberculosis (MDR TB) is a grave danger to public health because strains of mycobacterium tuberculosis become resistant to the two drugs most commonly used to treat TB, isoniazid and rifampicin. This form of TB is practically incurable by standard treatment, leading to increased morbidity and mortality rates. There were about 450,000 MDR TB cases globally in 2021 (WHO data).

Extensively Drug-Resistant Tuberculosis (XDR TB)

Apart from MDR TB, there is the danger of extensively drug-resistant TB (XDR TB). This type of infection is resistant to the most powerful drugs used against TB. While XDR TB is rare, infected patients are left without many treatment options or are treated with medication that is not as effective.

The biggest risk of developing XDR TB is for people with HIV or other immunocompromising health conditions. This group of people is also at a higher risk of dying from the infection.

2. Myths in developed countries that TB is no big deal

In many parts of the world, people are not well-informed about TB, its symptoms, prevention, and treatment, which leads to delayed diagnosis and the further spread of the disease.

• The perception might stem from the fact that TB is more prevalent in low- and middle-income countries, leading some in developed nations to believe it is not a significant concern.
• Advanced healthcare systems and effective treatments in developed countries may create a false sense of security. After all, when people are diagnosed and treated early, and preventive measures are in place, many communities do not see many TB cases, leading them to think it may not be a huge concern. 

3. Limited funding for TB-related awareness initiatives

There is a lack of funding for (TB) elimination efforts compared to cancer and heart disease. 

For the End TB 2023-2030 plan, WHO estimated that US $249.98 billion would be needed.

However, funding has been significantly lower than the amount required. For example, WHO notes that in 2020, global spending on TB-related services dropped (for the first time since 2016) to $5.3 billion—an 8.7% reduction from 2019-2020.

This can be due to factors like:

• People in developed countries may think of TB as a thing of the past, which means there is minimal urgency or prioritization for this infectious disease. 
• TB mainly affects low- to middle-income countries in Asia and Africa. These regions tend to receive less attention and resources. 

4. Inadequate disease surveillance and reporting

In India, for example, which has the highest number of TB cases and deaths, 70% of healthcare is provided by a fragmented private sector. Without universal healthcare, it is challenging to ensure accurate and early diagnosis and reporting, poor patient compliance with treatment protocols (since TB treatment takes months), and a high drop-out rate.

5. Poor living conditions

Overcrowded living conditions and poor sanitation, often seen in developing countries and among refugees or homeless populations, facilitate the spread of the TB bacteria. 

Without nutrition, adequate living conditions, and effective and easy access to affordable healthcare, many communities are at a higher risk of getting a bacterial infection like TB and spreading the disease. Overcrowding and poorly ventilated work or home environments make things worse.

6. A lack of effective vaccination 

Currently, the TB vaccine in circulation is the Bacillus Calmette-Guérin (BCG). Developed over 100 years ago, the vaccine effectively prevents 120,000 deaths in children each year.

However, to eradicate TB, we need to address issues with the BCG vaccine:

• It does not provide lifelong immunity against tuberculosis.
• It does not protect against severe TB.
• BCG is not indicated for people with HIV or other immunocompromised conditions. However, this group of individuals is at a higher risk of getting severe TB.
• It is not effective against adult pulmonary TB and the infection in adolescents.
• It is Ineffective against drug-resistant strains of TB.

However, developing a new vaccine has proved challenging. While a few TB vaccine candidates are in trials, none have been approved for widespread use.

Image: Tuberculosis vaccine.

Recent years have witnessed significant breakthroughs in TB vaccine research, offering hope for improved protection against this deadly disease. Scientists have identified several promising vaccine candidates that show potential in preventing TB infections and reducing disease severity.

M72 TB vaccine

One such candidate is the M72 vaccine. M72 has shown potential in lowering the risk of active TB in adolescents and adults, including people living with HIV.

In a large-scale clinical trial conducted in South Africa, the M72 vaccine demonstrated an efficacy of around 50%, providing protection against active pulmonary TB. While the M72 vaccine was first developed by GSK (GlaxoSmithKline), it had been discontinued due to a lack of commercial viability.

However, the Bill & Melinda Gates Foundation and the Wellcome Group are funding a Phase 3 clinical trial of the M72 vaccine in African countries with a high rate of TB. 

VPM1002 TB vaccine

Another promising vaccine candidate is the VPM1002, a genetically modified version of the BCG vaccine. 

Early clinical trials have shown that VPM1002 is safe and induces a stronger immune response than the conventional BCG vaccine. Further research is underway to assess its efficacy in different populations and determine its potential as an improved TB vaccine. 

Initiated by the Max Planck Society and licensed to Vakzine Projekt Management (VPM) and the Serum Institute of India to produce, the vaccine is in ongoing phase 3 trials.

MTBVAC TB vaccine

A new TB vaccine, MTBVAC, developed by India-based Bharat Biotech in partnership with Biofabri, is about to enter Phase 3 trials in 2023. This vaccine aims to be more effective in newborns, adolescents, and adults. 

Based on early results, the company notes that the vaccine may also prevent the spread of TB.

These promising candidates bring hope for better protection against TB, especially for regions with high TB burdens. 

While the search for an effective TB vaccine continues, early detection through testing and prevention strategies remains crucial in controlling the spread of the disease. TB testing involves the tuberculin skin test and the more modern interferon-gamma release assays. These tests help identify individuals who may be infected with TB and require further evaluation and treatment.

TB prevention strategies include infection control measures, such as proper ventilation and personal protective equipment in healthcare settings. Additionally, targeted testing and treatment of individuals with latent TB infection can help prevent the progression of active TB disease.

Tuberculosis (TB) remains a global health challenge, causing millions of deaths each year. Despite efforts to eliminate the disease, progress has been slow, with TB cases reducing by only 8.7% from 2015-2022. 

Key countries like India and Indonesia are not on track to meet their elimination goals. Challenges such as drug-resistant strains, limited awareness, funding issues, and inadequate surveillance hinder the eradication of TB. 

Multidrug-resistant TB and extensively drug-resistant TB pose significant threats, and misconceptions in developed countries contribute to delayed diagnosis. Insufficient funding and a lack of prioritization further impedes TB elimination, along with the need for a new TB vaccine. 

Increased awareness, international collaboration, an effective vaccine, and adequate resources are crucial to overcome these obstacles. Only through concerted efforts can we hope to end TB in the near future.

GIDEON is one of the most well-known and comprehensive global databases for infectious diseases. Data is refreshed daily, and the GIDEON API allows medical professionals and researchers access to a continuous stream of data. Whether your research involves quantifying data, learning about specific microbes, or testing out differential diagnosis tools– GIDEON has you covered with a program that has met standards for accessibility excellence.

Learn more about rare infectious diseases on the GIDEON platform.