About 10 million people contract and over one million die from tuberculosis every year, most in countries far away from the wealthy West. But yesterday’s World Tuberculosis Day serves as a reminder that this very curable disease is a global problem – one that’s getting worse. The Covid-19 pandemic shows communicable diseases respect no borders, and TB remains a stubborn feature of Western cities, not just developing nations. With 150 cases per 100,000 people, parts of London in the recent past had higher TB rates than Iraq or Rwanda, areas of New York City such as Sunset Park or West Queens in 2019 had rates six times the national average, and French experts last year have worried again about “hotspots” in northern Paris.
Three things compound this problem. Before becoming active and infectious, usually attacking the lungs, TB can lie dormant for years. Experts estimate that about one in four people alive today – roughly two billion – carry latent TB and around 10 percent of them will develop active TB over a lifetime. That means the 10 million people who develop active TB every year represent only the tip of the iceberg. The world has many people enduring active TB – and is teeming with latent TB cases constantly morphing into infectious ones.
The second problem is that Covid-19 forced us to take our eye off the ball. As the world has concentrated on testing for and tracing the SARS-CoV-2 pathogen, testing for and tracing TB plummeted. Deaths from this bacterial disease had fallen from 1.7 million in 2000 to 1.2 million in 2019. But our recent inattention means TB numbers are expected to rise again. The Stop TB partnership of governmental and non-governmental groups reckons we could easily face an extra 1.4 million deaths and 6.3 million active cases over the next five years. It’s safe to assume that the number of additional, new latent TB cases is many multiples higher.
Thirdly, we have to contend with this enlarged reservoir of latent TB just as the world limbers up again after various waves of Covid-19-induced lockdown. People all over the world will travel again and they will congregate to study, do business or enjoy just being together again. As the world begins to teem again, millions of people will develop active TB after months or years of carrying the latent disease undetected in their bodies. Their symptoms may be mild and go undiagnosed and untreated for months. The World Health Organization (WHO) reckons such sufferers can infect 10–15 other people over a year.
The confluence of these factors means the 1500 organizations of the Stop TB partnership fear that the fight against TB could be set back by five to eight years. The governments in the WHO want to cut annual TB deaths by 90 percent from 2015 levels and annual new cases by 80 percent by 2035 – by screening for latent TB and preventing cases from becoming active, by testing for and treating active cases and tracing contacts. If Stop TB’s warnings prove correct, its resolute actions over recent years will have been undone.
Luckily, the sterling work of the WHO, Stop TB and their partners, which work under the umbrella of the United Nations, means this worst case is not a foregone conclusion. The world can redouble its anti-TB measures to identify and treat people with TB and quickly shrink the recently enlarged pool of undiagnosed cases. That would require a resounding return to screening for and treating latent cases, as well as ramped-up testing for active cases alongside community engagement and contact tracing. That means we have to make sure that as many latent and active TB sufferers as possible get access to the right treatment as quickly as possible.
Ironically, there are two legacies of our response to Covid-19 that should give us hope for TB. Many health systems now have unprecedentedly large testing and tracing infrastructures that we can use to test for TB. Equally, ordinary people the world over have in the past year come to understand, support and even undergo tests for disease. This “testing mindset” allows governments to create unprecedented momentum for screening campaigns against latent TB. TB is one of the oldest infectious diseases whose traces have been found in ancient Egyptian pharaohs’ mummies. It has been haunting mankind for millennia. We still have a chance to finally get it under control.
Photo: ThitareeSarmkasat, Getty Images