Matthew J. Saunders, Carlton A. Evans
European Respiratory Journal 2020 56: 2001348; DOI: 10.1183/13993003.01348-2020
The global health community must learn from COVID-19 and take action now on tuberculosis and its social determinants, potentially saving millions from a preventable and curable disease https://bit.ly/2LLgLgA
The coronavirus disease 2019 (COVID-19) pandemic is likely to be the defining global health crisis of our generation. As the United Nations Development Programme highlighted in their recent call to action, the impact of this pandemic will extend beyond the immediate medical consequences to have far-reaching and long-lasting social and economic impacts, threatening to disproportionately affect poorer people in poorer countries. Income losses are anticipated to exceed USD 220 billion in developing countries, where many people live day-to-day without access to social protection, and food security is precarious. Strikingly, a recent United Nations study suggested that the social and economic consequences of the COVID-19 pandemic could increase the number of people living in poverty by as much as half a billion, with the majority of these newly poor people living in Africa, South-East Asia, and Central and South American.
COVID-19 and tuberculosis epidemiology
COVID-19 is likely to have catastrophic effects on tuberculosis, another global pandemic (figure 1). Tuberculosis has long been the world’s leading infectious killer, until on 1 April, 2020 COVID-19 overtook tuberculosis as the infectious disease killing the most people per day. It is no coincidence that the areas of the world predicted to be most affected by the social and economic consequences of COVID-19 are also the areas with the highest tuberculosis burden. This is because tuberculosis is a social as well as infectious disease: poorer, undernourished people living in densely populated areas are at higher risk of tuberculosis, and tuberculosis entrenches poverty by increasing costs, reducing income, and causing stigma and discrimination. Indeed, poverty is the key driver of the tuberculosis pandemic, with several studies demonstrating how tuberculosis incidence rates rise and fall in association with measures of socioeconomic development and social protection. In contrast, measures of biomedical care have had no detectable impact on tuberculosis incidence, despite helping to save millions of lives. If the estimates of impoverishment described above are tragically borne out, history warns us to soon expect a dramatic rise in tuberculosis incidence.
Mechanisms by which the COVID-19 pandemic is expected to worsen the tuberculosis (TB) pandemic.
COVID-19 and tuberculosis diagnosis
The COVID-19 pandemic is also likely to have a significant impact on the provision of biomedical care for tuberculosis-affected households. Access to diagnostic testing is likely to be reduced, partly because of limited human and material resources, but also because of the social stigma of having a cough or being unwell. This stigma has always been important for tuberculosis and has been exacerbated by the COVID-19 pandemic, potentially driving people with tuberculosis to hide their illness from others and delay accessing healthcare until disease and infectiousness are advanced. The World Health Organization (WHO) already estimates that approximately a third of people living with tuberculosis are either not diagnosed, treated, or reported. The COVID-19 pandemic might be expected to increase the number of these “missing” people, who are a major source of ongoing transmission and have a high risk of tuberculosis-related morbidity and mortality.
COVID-19 and tuberculosis treatment and prevention
Provision of appropriate treatment for people who are diagnosed with tuberculosis might also be affected, particularly for people with drug-resistant tuberculosis, due to disruptions in the production and transportation of medicines and supplies, reduced nutritional and mental health support, limited access to healthcare facilities, and reduced clinical care to manage adverse drug reactions and comorbidities, such as HIV, diabetes and cancer. Furthermore, impaired management of these comorbidities is also likely to significantly increase the risk of progression from latent tuberculosis infection to active disease in the general population. Relatedly, tuberculosis preventive treatment for household members is likely to be severely weakened, as strained health systems focus their limited resources on diagnosis and treatment, and visits to health facilities for non-emergencies are minimised. This is particularly alarming because transmission of tuberculosis to household members is likely to be increased by COVID-19, mediated by delayed tuberculosis diagnosis and heavier household tuberculosis exposure during household quarantine. Unfortunately, isolation and quarantine of unwell individuals within households is unfeasible for much of the world’s population living in crowded housing in the densely populated urban areas where most of the world’s tuberculosis occurs. This increased tuberculosis transmission is likely to be worsened by COVID-19-associated economic challenges, such as undernutrition, increasing tuberculosis susceptibility.
Preventing COVID-19 from worsening tuberculosis
Taken together, the social, economic and biomedical consequences of the COVID-19 pandemic are likely to combine to create a perfect storm with respect to tuberculosis. What can be done to address this evolving crisis? Many of us wish that we had done more, sooner to address the current COVID-19 pandemic; what lessons can be learned to prevent COVID-19 from causing a secondary tuberculosis emergency? Already, the WHO has issued an information note urging the continuity of essential services for people with tuberculosis during the pandemic. However, if much of the progress gained in tuberculosis care and prevention is not to be rapidly undone, further steps must be urgently taken to mitigate some of the broader impacts discussed above.
Social protection interventions
It is socioeconomic development and poverty that drive tuberculosis rates globally, so fighting tuberculosis in the context of COVID-19 demands that we address social determinants as well as biomedical care. Whilst people are unable to work, national and local governments need to be able to access funds to provide social protection to vulnerable populations at high risk of impoverishment, and therefore COVID-19 and tuberculosis, to reduce their risk. Provision should also be made for tuberculosis-specific social protection, which could take the form of cash transfers or food parcels for tuberculosis-affected households. Importantly, any economic support should involve engagement with patient civil society organisations, as they have a potentially critical role in providing psychosocial support to tuberculosis-affected households, reducing stigma and discrimination. This may harness digital technology to improve equity and efficiency, and overcome the infection control challenges associated with both tuberculosis and COVID-19. Tuberculosis-specific social protection should improve equitable access to tuberculosis care and prevention, reduce poverty-related tuberculosis risk factors, and therefore improve outcomes.