The virtual 52nd Union World Conference on Lung Health (WCOLH) opened Tuesday by announcing three major scientific developments that will potentially impact the global response to tuberculosis (TB), the world´s second biggest infectious disease killer behind COVID-19.
The event takes place against the backdrop of ongoing COVID-19 vaccine inequity, with the pandemic continuing to impact the delivery of TB services in many low- and middle-income countries.
COVID-19 and TB are today the world´s two leading infectious disease killers. The novel coronavirus pandemic has refocused attention on how infectious diseases transmit from person to person and has catalysed innovations in sampling and diagnostics. The disruption to TB services during the pandemic has only highlighted just how important it will be going forward that testing for and treating TB are made simpler and easier to access.
Researchers question assumptions of how TB is transmitted
In the opening press conference, researchers from the University of Cape Town in South Africa announced results from their study of TB positive people carried out in the specially constructed Respiratory Aerosol Sampling Chamber (RASC) which suggest that coughing, thought previously to be the main means of spreading TB, might not be the primary driver of TB transmission. Instead, tidal, or regular, breathing may be a far more significant contributor to the aerosolization of Mycobacterium tuberculosis, the bacterial cause of TB.
“This study is an important step forward in our understanding of aerosol transmission of disease and its findings are as relevant for COVID-19 as they are for TB,” said Guy Marks, President of The Union, convenor of the World Conference. “It will hopefully generate more focus on the topic of airborne spread of respiratory diseases.”
Lead author of the study, Ryan Dinkele of the University of Cape Town, said if tidal breathing is a primary driver, or even as important as cough in TB transmission, then symptomatic screening for TB-transmitters may not be useful in slowing the spread of the disease.
“The current approach, which relies on the testing and treatment of passively identified individuals may not be a reliable response to preventing transmission, as it depends on people feeling sick enough to seek treatment,” said Dinkele. “It may also shed light onto why constructing transmission chains is so challenging in high TB burden settings.”
Fingerstick blood test can detect TB in less than an hour
The development of a fast and accurate, non-sputum-based point-of-care triage test for tuberculosis (TB) would have a major impact on combating the TB burden worldwide. A new fingerstick blood test has been developed by Cepheid (Xpert-MTB-Host Response (HR)-Prototype).
Jayne Sutherland of the MRC Unit The Gambia at LSHTM, reported interim results of the Xpert-MTB-HR prototype trialled in a prospective, multi-site study across Gambia, Uganda, South Africa and Vietnam. The device is the first to meet the WHO target product profile for a Triage test for TB regardless of HIV status or geographical location. It takes under 1 hour and uses fingerstick blood, rather than sputum, which reduces biohazard risk and increases likelihood of diagnosis in individuals who cannot readily produce sputum such as children and people living with HIV.
Face-mask sampling can predict acquired Mycobacterium tuberculosis infection in household contacts
Caroline Williams, Clinical Lecturer in Infectious Diseases at the University of Leicester in the UK, reported on the use of masks to see if bacteria could be detected on the mask and therefore could potentially be used to detect infectiousness earlier than with sputum. Mask sampling could detect viable bacteria and those patients with higher levels on their mask correlated with increased infectiousness determined by new infections in their close contacts.
Earlier in the press conference pediatric TB doctor Uvi Naidoo described his experience of surviving TB a few years ago and two bouts of COVID-19 in 2020.
It took a little over three years of treatment until he was cured of MDR-TB. He sustained numerous life-threatening complications – many due to dated TB tools and drugs still in use today. 10 years later today, Naidoo acquired severe COVID-19 twice from patients he treated within the past year. Like many other nurses, doctors and the general public he has seen death on a personal and heartfelt level.
“While admitted for COVID-19, I saw patients’ demise from COVID19, medical colleagues break down from sheer emotional and physical fatigue and watched my whole family admitted to ICU for COVID19, losing my dear father,” said Naidoo.
“We’ve all been humbled. There have been far too many gaps for too long and too many continue to suffer. From the political realm to basic sciences and clinical bedside, it’s high time we all show we care. It’s time to roll up our sleeves in service to those that really need us.”
Union Ambassador, actor Claire Forlani, said the coronavirus pandemic has highlighted the absence of interest and care from those communities most affected by the virus.
“Is it any wonder that vaccine inequity is front and center,” said Forlani. “The failure to deliver COVID-19 vaccines to low- and middle-income countries and to end tuberculosis are two sides of the same coin – a devaluation of human life in poor countries.”