Dr Abena Jean-Louis is the regional public health expert at WHO AFRO, who is leading efforts to combat tuberculosis and strengthen laboratory systems across Africa. In this interview with SADE OGUNTOLA, he talks about what individuals need to know about the disease and its importance to human health and the economy. Excerpts:
What is the economic burden of Tuberculosis (TB) in Nigeria and globally?
In Nigeria, TB creates significant financial hardship. Patients and families often struggle with high costs for treatment, travel, and food. Many cannot afford care on their income. Nigeria also faces a large funding shortage for its TB programs – about 60 per cent of the needed budget for 2024 was unfunded. This lack of funds makes it harder to control the disease. Globally, TB mostly affects adults during their working years, causing major losses in income for families and impacting national economies. The burden includes healthcare costs and the wider effects on society.
Drug resistance is an issue with TB. Why is this, so, and what is its implication?
Sometimes, the TB germs change (mutate) so that the usual, most effective medicines no longer work against them. This is called Drug-Resistant TB (DR-TB). It can happen if people don’t finish their full TB medicine course, get the wrong treatment, or catch TB from someone who already has a resistant type. Nigeria estimated thousands of new cases of TB resistant to standard drugs in 2023.
DR-TB is a serious problem. It’s much harder, takes longer (months or even years), and is more expensive and difficult to treat. The medicines used have more side effects, and the chances of a cure are lower, while the risk of death is higher. People with DR-TB can also spread these hard-to-treat germs to others.
Can you assess individuals’ TB treatment access in Nigeria?
Nigeria has improved access. In 2023, about three out of four people estimated to have TB were officially reported and likely started treatment. For those who start treatment, the cure rate is quite good for first-time patients (around 93 per cent). However, it’s lower for those who have had TB before or who also have HIV.
Still, challenges exist. Not everyone who needs treatment gets it. Problems include weaknesses in the health system, difficulties finding all TB cases, insufficient involvement from private clinics, and costs that stop patients from completing treatment.
What will you consider the topmost risk factor for TB in Nigeria?
While several things increase TB risk, HIV infection is a major one in Nigeria. HIV weakens the body’s defences, making people much more likely to get sick with TB. Many thousands of new TB cases in Nigeria each year are among people living with HIV. Other key risks include poor nutrition (malnutrition), which weakens the body’s defenses, and poverty, which is linked to poor living conditions and difficulty accessing healthcare.
Children are given BCG, why then do we still have cases of TB in adults and sometimes children?
The BCG vaccine given at birth helps protect young children from the most severe forms of TB (like TB affecting the brain). However, it doesn’t work very well to prevent TB in the lungs (the most common type) in older children and adults. The protection also fades over time. So, even if someone got the BCG vaccine as a baby, they can still get infected with TB germs later and develop the disease, especially if their body’s defenses are weak.
Is TB still of concern, and why?
Yes, definitely. TB is still a very serious health threat in Nigeria and globally. TB remains a significant concern both in Nigeria and globally. It is a very serious health threat due to several critical factors. Nigeria experiences a high volume of TB cases; in 2023, it was estimated that nearly half a million people contracted the disease, and over 70,000 deaths occurred, equating to hundreds of deaths daily. Drug-resistant TB (DR-TB) poses a growing challenge, making treatment more complex. Furthermore, TB is a leading cause of death among individuals living with HIV. The spread of TB is also fueled by poverty and poor nutrition. Lastly, insufficient funding hinders the ability to effectively combat the disease.
What are the challenges surrounding TB treatment in Nigeria?
Nigeria is fighting an uphill battle against tuberculosis (TB), but major obstacles are slowing progress. Money is a big problem—the country relies heavily on international aid to fund TB programs, with only 15 per cent of the needed budget coming from local sources. In 2024, Nigeria’s TB plan was left 60 per cent unfunded, meaning clinics, medicines, and outreach efforts are stretched thin.
Finding everyone with TB is another hurdle. Experts estimate half a million Nigerians get TB each year, but nearly a quarter of cases go undiagnosed. Many people don’t get tested due to a lack of awareness, stigma, or limited access to health centres. Even when diagnosed, treatment isn’t always smooth—hospitals sometimes run out of drugs, and health workers are in short supply.
Drug-resistant TB makes things even harder. These tougher strains require expensive, lengthy treatments, and while 84 per cent of patients recover, the costs and side effects push many to abandon care. At the same time, seven in 10 families dealing with TB face financial crisis from medical bills and lost income, forcing impossible choices between health and survival.
The good news is that more people living with both TB and HIV are getting life-saving antiretroviral therapy (93 per cent coverage), and better diagnostics are helping. But without more funding, stronger health systems, and efforts to tackle poverty and stigma, TB will keep spreading needlessly.
A study linked under-nutrition to the occurrence of new TB cases. How do you explain this?
Not getting enough food or the right nutrients weakens the body’s natural defenses, making it harder to fight off germs. Normally, a strong immune system can keep TB germs under control even after infection. However, when someone is malnourished, their weakened defenses make them more likely to get infected with TB if exposed, and also more likely for a hidden (latent) TB infection they already have to turn into active sickness. Therefore, good nutrition is very important in preventing TB and helping the body fight it.
Disease patterns are not static; they keep changing. Are there things that are now increasing the spread of the infection in Nigeria?
Yes, several things contribute to the ongoing spread of TB in Nigeria. The high number of people living with HIV makes more individuals vulnerable to TB. Poverty is also a major factor, as poor living conditions like overcrowding and lack of access to good food and healthcare help TB spread easily. Additionally, the rise of drug-resistant TB means some people can remain infectious for longer, spreading these harder-to-treat germs. The growth of cities can also play a role by leading to crowded living, and widespread poor nutrition weakens people’s ability to fight off the infection.
TB is said to be the leading killer of people with HIV. Why is the disease still killing people even though it is treatable?
It’s tragically true that even with treatments available, TB remains a top killer for people living with HIV. There are several reasons for this. HIV severely damages the body’s defenses, and even with HIV treatment, it can take time for these defenses to recover, leaving people vulnerable to TB. Often, either TB or HIV isn’t diagnosed until the person is already very sick. Managing both diseases at once is also challenging, involving complex medical routines, potential side effects, and drug interactions. Furthermore, drug-resistant TB is even harder to cure in people with HIV. Sometimes, as HIV treatment starts to restore the immune system, it can cause a strong, potentially harmful reaction to the TB germs. Finally, difficulties in accessing regular healthcare and sticking to long treatment plans contribute to poorer outcomes and continued deaths.
How does TB kill?
TB usually attacks the lungs first, where the germs damage the tissue. If it’s not treated, this damage can get so bad that the lungs stop working properly, meaning the body can’t get enough oxygen. TB germs can also spread from the lungs to other parts of the body, like the brain or kidneys, causing serious harm there. In very severe cases, the infection can overwhelm the body, leading to a life-threatening condition called septic shock. TB can also make other existing health problems worse.
There are different types of TB. So, which one is the most dangerous?
While any active TB is serious, the most dangerous types are those that are resistant to medicines, known as Drug-Resistant TB (DR-TB). This includes TB that doesn’t respond to the main drugs (MDR-TB) and, even worse, TB that resists backup drugs too (XDR-TB). These types are so dangerous because treatment options are very limited, the treatment takes much longer, the medicines have more side effects, and the chances of being cured are lower.
How will undernutrition, forced displacement, and homelessness affect the 2035 TB targets?
The world aims to dramatically reduce TB deaths and new cases by 2035. However, problems like poor nutrition, people being forced from their homes, and homelessness make reaching this goal much harder. People in these difficult situations are more likely to get sick with TB because of weakened body defenses, poor living conditions, and stress. It’s also extremely hard for them to get diagnosed and complete the long treatment; for example, homeless people often have very low cure rates. These conditions can also help TB spread more easily. Unless these social problems are addressed, achieving the 2035 TB targets will be very difficult.
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Meteorological factors are said to contribute to the risk of pulmonary tuberculosis… Can you explain how low temperature, relatively high wind speed, and low relative humidity influence conducive transmission of pulmonary TB?
The link between weather and TB is complex, but researchers are looking into possibilities. Some think TB germs might survive longer in tiny airborne droplets in cold, dry air. Also, people stay indoors more in cold weather, which could increase exposure if someone infectious is present. Low humidity might also affect our breathing passages’ defenses. High winds might scatter infectious droplets outdoors, reducing risk, but indoors, people might close windows, reducing fresh air and potentially increasing risk. It’s important to remember, though, that things like poverty, healthcare access, nutrition, and crowding usually play a much bigger role in TB spread than weather alone.