Tuberculosis Preventive Treatment: The next chapter in elimination of TB in India

Tuberculosis is a disease of great antiquity and affects some 10 million people yearly, development of drug resistance and HIV infection, makes Tuberculosis an important public health problem. Recent scientific advances bear out the hope that given the necessary political will, scientific and financial support, time may be ripe to work towards elimination of Tuberculosis as a public health problem.

Tuberculosis (TB) is an infectious disease caused by the bacterium Mycobacterium tuberculosis. It primarily affects the lungs, but can also affect other parts of the body such as the brain, kidneys, and bones. The age old practice in all Indian household is to boil milk, thus blocking any chance of transmission of Mycobacterium bovis from an infected cow.

The natural history of TB varies depending on a number of factors, including the individual's immune system, the strain of the bacterium, and the type and duration of treatment.

Generally, the initial infection with TB may not cause any symptoms and can remain dormant in the body for years. This is known as latent TB infection, and individuals with this form of TB do not feel sick, are not contagious, and do not develop the disease unless the infection progresses to ?active disease. An infected person has about 10% risk of developing TB disease and the risk diseases as time passes, unless the host becomes immunocompromised.

In some cases, the bacterium can become active and cause TB disease, which can present with symptoms such as cough, fever, night sweats, weight loss, and fatigue. Active TB is contagious and can spread from person to person through the air when an infected individual coughs or sneezes.

Without treatment, TB disease can progress and cause serious complications, including damage to the lungs and other organs, as well as death. However, active disease can be diagnosed using very sensitive molecular methods and a number of effective drugs are available, which if taken for the time prescribed, would lead to complete cure.

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When a person (especially child) ?comes into contact with someone who has active tuberculosis (TB), they can potentially become infected with the bacteria that cause TB. However, not everyone who is exposed to TB will develop an infection or disease.

The progression from contact to TB infection to TB disease can be summarized as follows

1. Contact with TB: The first step is contact with someone who has active TB disease. This can occur when a person is in close contact with an infected individual, such as living in the same household or spending prolonged periods of time together. Children below 5 years of age are at special risk.
2. TB infection: When the bacteria that cause TB enter the body, the immune system will attempt to fight them off. In many cases, the bacteria are contained by the immune system and the person will not develop active TB disease. Instead, the bacteria will remain dormant in the body, and this is known as latent TB infection.
3. Active TB disease: If the immune system is unable to contain the bacteria, they will begin to multiply and cause active TB disease. This usually happens within the first few years after infection, but can occur many years later. The symptoms of active TB disease can include cough, fever, night sweats, weight loss, and fatigue.

The End TB Strategy is a global plan developed by the World Health Organization (WHO) to reduce the burden of tuberculosis (TB) and achieve a world free of TB. The strategy was launched in 2015 and aims to reduce the number of TB deaths by 90% and to cut new cases by 80% by 2030, compared to 2015 levels.

The End TB strategy has three pillars:

1. Integrated, patient-centered TB care and prevention: This pillar aims to ensure that all people with TB have access to high-quality diagnosis, treatment, and care. This includes strengthening health systems, engaging communities, and addressing the social determinants of TB.
2. Bold policies and supportive systems: This pillar aims to create an enabling environment for TB control by promoting universal health coverage, social protection, and multisectoral action. This includes measures such as increasing investment in TB research and development, promoting equitable access to TB services, and ensuring that vulnerable populations are not left behind.
3. Intensified research and innovation: This pillar aims to accelerate the development of new tools and strategies to prevent, diagnose, and treat TB. This includes investing in research and development of new TB drugs, diagnostics, and vaccines, as well as promoting the use of digital technologies to improve TB care and prevention.

In the first pillar is included preventive treatment of persons who have been exposed to tuberculosis and have an immune response to specific antigens of the pathogen, but are not having any symptom of disease. This is called tuberculosis?preventive treatment (TPT) should be administered to individuals who are at risk of developing TB disease. LTBI is a condition where a person is infected with the TB bacteria but does not have active TB disease. Without treatment, there is a risk that the LTBI may progress to active TB disease in the future. TB preventive treatment can help reduce this risk.

TB preventive treatment is recommended for people with LTBI who are at high risk of developing TB, such as:

• People living with HIV
• Children under the age of five who have been in close contact with someone with TB
• People who have had recent contact with someone with infectious TB
• People with conditions that weaken the immune system, such as diabetes, chronic renal failure, or cancer
• People receiving immunosuppressive therapy, such as corticosteroids or chemotherapy

TB preventive treatment involves taking medication for a period of 3 to 9 months, depending on the medication used. The medication is highly effective in preventing the progression of LTBI to active TB disease.

In addition to TB preventive treatment, it is also important to implement measures to prevent the transmission of TB, such as early diagnosis and treatment of people with active TB disease, infection control measures in healthcare facilities, and promoting awareness of TB symptoms and transmission.

It is difficult to say whether tuberculosis (TB) would be eradicated in the near future, as there are several challenges that need to be addressed to achieve this goal.

TB is a complex disease that is deeply rooted in social and economic factors, which can make it difficult to control and eliminate. Factors such as poverty, malnutrition, poor living conditions, and weak health systems can contribute to the spread of TB and hinder efforts to control the disease.

Furthermore, the TB bacterium can develop resistance to the drugs used to treat it, making it more difficult to cure and increasing the risk of transmission. This is known as drug-resistant TB, and it is a growing concern worldwide.

Despite these challenges, there have been significant achievements in the fight against TB in recent years. For example, the global TB incidence rate has been declining slowly but steadily, and there has been progress in the development of new drugs and diagnostics for TB.

To achieve TB eradication, there needs to be a sustained commitment from governments, civil society organizations, and the private sector to implement the End TB Strategy and strengthen health systems. This includes ensuring universal access to high-quality TB care, investing in research and development of new tools and strategies, and addressing the social and economic determinants of TB.

In summary, while TB eradication is a challenging goal, significant progress has been made, and sustained efforts can help to reduce the burden of TB and move closer to the goal of TB eradication.