In the midst of the all-encompassing coronavirus crisis, focus on the tuberculosis (TB) epidemic has waned. TB has been infecting humans since ancient times, with scientists divided on where it originated from and when it was transferred to humans. What we do know is that on 24th March 1882, German microbiologist Robert Koch discovered Mycobacterium tuberculosis, the bacteria that infects the lungs in the initial stage. To mark this life-changing discovery, World Tuberculosis Day takes place on 24th March each year, with the aim of raising awareness of this deadly disease.
World Tuberculosis Day serves as an important reminder that we should return our attention to TB. In light of the coronavirus pandemic, the situation is now more urgent than ever. This is because, like COVID-19, TB primarily affects the lungs, and patients and survivors often have lung damage as a result. It is therefore supposed that TB sufferers are at a higher risk of more severe symptoms of coronavirus. Although this will likely be taken into account in medical settings, TB will remain a significant threat to human life, even when the COVID-19 situation eases.
With modern scientific advancements, measures have been undertaken to decrease the prevalence of the disease, including the dissemination of the Bacillus Calmette–Guérin vaccine, and treatment of the active disease with phases of drugs. Unfortunately, however, the vaccine has limitations, including only 60%–80% efficacy against severe forms of TB in children. As well as this, in the 1980s, a drug-resistant form of TB was discovered, which caused a rapid increase in infections and fatalities and led the WHO to declare a global health emergency in 1993. This strain is still being spread globally and there is currently no effective cure. The race to produce a more effective vaccine and new targeted drugs is on. Accordingly, the theme of this year’s TB day is “The Clock is Ticking”, reminding us all just how pressing the search for an antidote is.
Currently, it is estimated that around a quarter of the world’s population are infected. According to the WHO, TB is curable and preventable, but in spite of this, 1.4 million people died from the disease in 2019. People at higher risk of contracting TB include those living with HIV, those with poor nutrition, diabetics, smokers and heavy drinkers. People of working age are most likely to be affected, and men are more likely to be affected than women. Crowded living conditions also allow for the disease to spread more quickly, meaning that prisoners are particularly at risk. The risk of contracting TB is also greater depending on country of residence—India, China, the Philippines, Pakistan and Nigeria have the highest rates of TB worldwide. However, TB is a global disease that can affect anyone in any country. Even in the lowest incidence countries, there are often thousands, sometimes tens of thousands, of people infected every year.
There are two different forms of TB—latent TB and active TB. A person with latent TB is someone who has contracted TB from an active TB sufferer, but does not have symptoms, nor can they pass it on to anybody. However, like a dormant volcano, latent TB can be activated, meaning that the sufferer will develop symptoms further down the line. Most people with latent TB develop active TB within five years. Once symptomatic, the sufferer will then become contagious, spreading it to others. As the symptoms can be rather mild at first, the patient is unlikely to realise that they are passing it on. The existence of latent TB arguably makes TB, as a whole, more dangerous and difficult to control, as it is more difficult to keep track of people with latent TB; it can re-emerge years later, and after the patient has moved to a new city or country. Two tests, the tuberculin skin test and Interferon-gamma release assays, can be used to determine whether someone has latent TB, but there are limitations to both of these tests. A patient will test positive for latent TB if they have previously had TB and recovered. The test also struggles to predict which latent TB cases will eventually become active TB cases. The need for smarter testing is clear, and it will help countries to track, treat and prevent TB in the population.
In order to achieve this goal and protect future generations, research on tuberculosis is critical to find new ways to stop the spread of the disease. For example, the discovery of vital information, such as markers that could indicate those people most likely to be at risk of becoming infected with TB, can help halt transmission and save lives. Research related to the development of vaccines, anti-TB drugs and better testing is also crucial to ending the disease.
The United Nations outline, in one of their Sustainable Development Goals (SDGs), the target of ending TB infection completely by 2030. On 26th September 2018, world leaders reaffirmed their commitment to end the TB epidemic by 2030, with USD 13 billion pledged to prevention and care, and USD 2 billion pledged to research.
Sharing this research with other TB scholars will also enable a quick, highly collaborative effort to end infection. It is hoped that open access, which allows readers free and easy access to research, will help in this process. For example, in MDPI journals (all of which are open access), numerous Special Issues and research papers are dedicated to TB, including “Tuberculosis: Clinical Applications in the Diagnosis and Treatment” (https://www.mdpi.com/journal/jcm/special_issues/Tuberculosis_TB) in Journal of Clinical Medicine in 2019, and “Mycobacterium tuberculosis Pathogenesis, Infection Prevention and Treatment” (https://www.mdpi.com/journal/pathogens/special_issues/Mycobacterium_tuberculosis) in Pathogens in 2020.
We are fully committed to publishing important research to end TB’s threat to human life. It is with great hope that we envision a future in which both COVID-19 and tuberculosis are eliminated, and we have been victorious in the war on viruses. MDPI will continue to publish Special Issues related to TB and the UN’s goal of ending the TB epidemic by 2030.