As the COVID-19 pandemic claims lives across the planet and eclipses all other news, it is easy to forget that it is not the only pandemic harming people across the globe. Tuberculosis (TB) has been found in the bones of ancient mummies and in the lungs of young children in the present. It has insidiously woven itself into the fabric of humanity over millennia, shaping culture along the way. Although it does not dominate news cycles like the younger pandemic, TB remains a serious global health crisis today.

Tuberculosis Today

Annually, about 10 million people develop TB, and an estimated 1.5 million die from their disease, which makes it the leading infectious killer worldwide, even in the time of COVID-19. Tropical and subtropical countries are most severely affected, but the United States is not immune to TB and its impacts. New York City suffered a TB outbreak in the 1980–90s during which TB rates in the city rose sharply to the levels of endemic countries such as Bangladesh. Almost 4,000 New Yorkers became sick, and containing the epidemic cost more than a billion dollars. Although the United States has a very low incidence of TB (approximately three cases per 100,000 individuals), certain populations such as Pacific Islanders and Native Americans, foreign-born individuals, and people experiencing homelessness remain at higher risk of contracting TB and transmitting this airborne infection.

In our hyperconnected world, TB can rapidly spread from high incidence countries such as South Africa to those with low case burdens such as the US and produce outbreaks such as the one in New York City. Recognizing that TB anywhere is TB everywhere, the World Health Organization’s (WHO’s) End-TB Strategy aims to end the global TB pandemic by 2035. Since its launch in 2015, the strategy has marshalled unprecedented political will, international collaboration, and funding to develop better diagnostic tests, new drugs, and a new vaccine. However, we have not even reached the halfway mark in our goal of reducing new TB cases by 20 percent and TB deaths by 35 percent by 2020. The reason for this disappointing progress might be underinvestment in a therapy we already have: food.

Undernutrition And Tuberculosis

Key factors can significantly increase an individual's risk. In particular, 2.3 million cases of TB were worldwide attributable to undernutrition in 2018: That’s one in five cases. By comparison, 1.2 million cases were attributable to HIV and 0.8 million cases to diabetes—risk factors that receive considerably more attention and funding. Undernutrition blunts the function of the immune system and increases the risk for TB so much so that it is likened to HIV/AIDS and called “nutritionally acquired immunodeficiency syndrome” or N-AIDS. Undernourished patients with TB get sicker, have more extensive lung damage, and are more likely to die from TB. The COVID-19 pandemic has further exacerbated the situation by threatening the financial security of socioeconomically vulnerable individuals and disrupting food distribution networks. Wealthier countries are not immune to the food insecurity wrought by the pandemic.

We can do something about this.

Based on modeling studies, feeding an undernourished individual and increasing their body mass index (BMI) from 16 to 20 would decrease their risk for TB disease by about 50 percent. This would be as beneficial as the new TB vaccine, which is generating great enthusiasm. Of course, feeding people has benefits beyond mitigating TB risk: prevention of complications from vitamin and mineral deficiencies, protection against other infectious diseases, increased economic productivity, and decreased human suffering due to hunger.

Indeed, records from England showed that between the two World Wars, rates of TB dropped to one-third of their level between 1913 and 1940 even before the discovery of any effective medicines for TB. Similar trends were noted in the United States in the nineteenth and early twentieth century due to similar socioeconomic advancement, the rise of sanatoria, and burgeoning public health expertise.

Tuberculosis As A Social Disease

Writing in the early twentieth century, the famed physician Sir William Osler described TB as a “social disease with a medical aspect.” Today, socioeconomic determinants of health continue to keep TB entrenched in society, particularly for the most vulnerable. However, with the discovery of TB medicines, public health efforts have become excessively focused on diagnosing and treating TB once it is contracted. Public health officials and researchers should also focus on prevention, mitigating the risk factors that drive TB, such as undernutrition, which is perhaps the best biomarker of inequity and neglect.

Screening and treatment for undernutrition should be integrated with TB care as has already been done for important comorbidities such as HIV and diabetes. Addressing undernutrition requires stronger international social protection programs—such as India’s Targeted Public Distribution System (TPDS), which provides subsidized food ingredients to impoverished Indians. Programs such as this also support family members of TB patients, who are at a high risk of developing TB.

To be sure, governments, non-governmental organizations, and international aid organizations have consistently supported nutrition programs for children and pregnant women, but there has been limited political appetite for broader nutritional interventions for vulnerable adults. It is time to change that. The first step to doing this is to provide policy makers with evidence that investing in eliminating chronic undernutrition will make a meaningful impact while also being cost-effective. Unlike funding for TB therapeutics and diagnostics studies, research questions at the intersection of nutritional science and TB have not thus far received much funding.

Clinical, policy, and implementation research can answer key questions about expanding nutritional interventions. How much food do TB patients and their families need? How do we deliver food cost-effectively? Are cash transfers better interventions than food baskets? What can we do to buffer the food security of vulnerable individuals during pandemics?

The lack of political will and research funding to address nutrition and TB has been a key barrier to answering these questions. Furthermore, these studies require investments in long-term nutritional supplementation (can be perceived as never-ending), the effects of nutrition can be difficult to tease apart from those of other public health improvements, and the integration of nutrition and TB programs requires cross-disciplinary collaboration that can be challenging. The answers to these questions, however, can help governments and the WHO establish nutritional guidelines and design effective national and international programs. For instance, India could change the composition of the subsidized rations it provides impoverished Indians through the TPDS and target those at highest risk of TB disease.

The COVID-19 pandemic has set global TB elimination efforts back an estimated five to eight years. To meet the goals of the End-TB Strategy, we must take immediate and radical action. Continued investment in diagnostics, drugs, and vaccines is critical, but we must also invest in meals as we do in medicines. The only way to make rapid progress toward TB elimination is extend our work upstream and focus on prevention by addressing socioeconomic factors such as undernutrition. Yes, COVID-19 demands money and attention, but we cannot forget that TB is a persistent threat to the health of millions.

Media Contact
Mercy
Managing Editor
Journal of Food and Clinical Nutrition