25 Mar 2020

A Tale of Two Pandemics: a plea on World TB Day, 24 March 2020

LIV-TB is a cross-campus collaboration between the Liverpool School of Tropical Medicine and the University of Liverpool. In the following post, Dr Tom Wingfield talks about the current TB Pandemic. 

It is the worst of times. We are facing a pandemic.

A quarter of the world’s population is estimated to be infected. By the end of 2020, it is likely that 10 million people will have fallen ill, three million will not have been tested and treated, and over 1 million, mostly vulnerable people, will die.

This pandemic is not caused by the novel coronavirus, SARS-CoV-2, which leads to COVID-19.

It is caused by tuberculosis (TB).

Yesterday, on World TB Day 2020, and amid this unprecedented outbreak, we at LIV-TB and others think it is vital to compare and contrast the TB and COVID-19 pandemics - one old, one new - to remind ourselves why it’s still time to end TB. We have written a related comment that has been published here in Lancet Respiratory Medicine. 

So what is a pandemic? A pandemic is defined as a disease that spreads over a whole country or the whole world. TB and COVID-19 both fit this definition, affecting people across all six continents. No country is TB free and COVID-19 has now reached more than 180 of the nearly 200 countries on the planet.

There are striking similarities between the two pandemics. Both are a huge cause of illness and death around the world. TB is the single biggest infectious diseases killer, ending the lives of 1.2 million people in 2018. This is more than HIV and malaria combined. COVID-19 has infected nearly 250,000 people and caused nearly 10,000 deaths in the first quarter of 2020 alone. Both cause symptoms of fever, cough and shortness of breath. In countries with escalating COVID-19 cases, this is likely to mean that people with TB presenting to clinics and hospitals may go unrecognised or misdiagnosed. A similar pattern emerged in West Africa when cases of malaria were missed during the Ebola outbreak. Another similarity is that those at higher risk of more severe TB and COVID-19 disease and outcomes are older people and those with chronic illnesses. And, as we are discovering for COVID-19, both diseases lead to significant social impact including stigma, discrimination, and isolation; and economic impact related to country productivity losses and catastrophic costs to individuals and households.

There are also stark differences, the first being time. TB has accompanied us for thousands of years even being found in Egyptian mummies. SARS-CoV-2, on the other hand, is a new coronavirus that has spread rapidly around the world since December 2019. TB, previously known as consumption or The White Plague, is used to being labelled a pandemic. This is the first COVID-19 pandemic humankind has ever seen. Second, most children with COVID-19 will have only mild symptoms. The same cannot be said for TB, which in 2018 killed one in five of the 1.1 million children who became ill with TB. Finally, over 90% of TB cases and deaths occur in low- and middle-income countries. In contrast, Europe has been called the second epicentre of COVID-19 after China. Among other factors, this may explain why more funding and person-power will be put into the COVID-19 response in a year than TB has received in decades. However, modelling studies show us that vulnerable countries in sub-Saharan Africa and the Americas will soon be dealing with their own COVID-19 epidemics. We must all act together now to prevent a catastrophe.

There remain many unknowns. How TB and COVID-19 may interact is not understood. Put simply, TB rates could go up due to more people coughing due to COVID-19 who also have TB or go down due to self-isolation and quarantine. The risk factors for getting COVID-19 and having more severe disease appear to overlap and be similar to those for TB. These include being oldera smokermale, having other chronic illnesses such as lung disease, and being poor. Undoubtedly, COVID-19, like TB, will be associated with the medical poverty trap, in which poorer people have a higher likelihood of infection, disease, and adverse outcomes. Also, unemployed people, informal or zero-hour contract workers, will experience further impoverishment, which increases TB risk.

The best of times would be to live in a COVID-19 and TB-free world. But this is a long way off and there is much to do. So, as we work together to control COVID-19, let's not forget the ongoing TB pandemic; still the biggest infectious diseases killer. We need to markedly increase funding to strengthen healthcare systems to address TB and to support research for a vaccine, better tests and medicines, equitable access to care, and socioeconomic support for people affected by TB. We need to continue to inform, advocate for, and empower local communities and to lobby governments and policymakers, to ensure that TB, as well as COVID-19, remain high on the global agenda. The lessons we have been taught by pandemics, old and new, are to be proactive, long-sighted, to plan ahead, and to not become complacent. 

Let's look forward to the best of times.

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