Healthcare Workers Face Up To Six Times the Risk of Drug-Resistant Tuberculosis as General Population
Editor’s note: these studies are being released in the May 15 print edition of a special supplement to the journal Clinical Infectious Diseases titled “Healthcare Workers and Tuberculosis Prevention”. The full supplement is free to view.
New research suggests urgent action needed to combat tuberculosis among healthcare workers in poorer countries
ROCKVILLE, Md., USA (May 4 , 2016)—Globally, healthcare workers face three times the risk of contracting tuberculosis as the general population, and the risks of multidrug-resistant disease is higher still: up to six times higher for healthcare workers in South Africa, according to new reports that are part of a healthcare worker-focused supplement in the journal Clinical Infectious Diseases. Up to one-third of affected healthcare workers die of this airborne disease.
Study authors reported that risks are compounded by the lack of an effective vaccine and facilitated by neglect of basic infection control measures such as adequate ventilation. Furthermore, young, vulnerable healthcare workers often fail to appreciate the risks they face. Therefore, health workers who are crucial to ending the epidemic frequently become both victims and transmitters of the disease.
“A person dies every 21 seconds from tuberculosis, some of whom are frontline caregivers,” said Thomas G. Evans, co-editor of the special supplement of articles and formerly Chief Scientific Officer at Aeras, a nonprofit, global biotech organization developing new tuberculosis vaccines. “Ending the epidemic requires resources, political will, and innovation, starting with protection of our health workforce.”
Co-editor Professor Linda-Gail Bekker, with the Desmond Tutu HIV Centre at the University of Cape Town, South Africa, points to the impact of the tuberculosis epidemic. “The entire 2014–2015 Ebola outbreak killed as many people as die in three days from tuberculosis,” she said. “The majority of TB cases occur in 22 high-burden countries, where healthcare systems are often fragile and under-resourced.”
In 2014, there were an estimated 1.5 million deaths from tuberculosis, and 9.6 million people developed the disease. Nearly half a million of these are multidrug-resistant (MDR) tuberculosis, expensive to treat, difficult to cure—and largely undiagnosed. As such, MDR tuberculosis is a growing threat in high-burden countries, including in their healthcare facilities.
“The need to protect health care workers against tuberculosis, whether by vaccination, infection control or preventive therapy is especially important for national health systems, as they have the specialized role of caring for patients,” said the author of one of the studies, Mark Hatherill with the South African Tuberculosis Vaccine Initiative (SATVI) at the University of Cape Town.
Seven journal articles examine the impact of tuberculosis, MDR and XDR (extremely drug-resistant) tuberculosis on healthcare workers; the major risk factors they face; myths and stigma that fuel its spread; ethical issues underpinning the epidemic among healthcare workers; and the measures needed to end the epidemic.
South African healthcare workers face dual epidemic
South Africa has one of the highest rates of tuberculosis and of HIV in the world. More than six million South Africans are infected with HIV, and there were 450,000 active cases of tuberculosis in 2013, with more than 26,000 multi-drug resistant. Co-infection is common, and healthcare workers living with HIV are at a 20- to 50-fold higher risk of developing tuberculosis disease than those who are HIV-uninfected, according to Arne von Delft, author of one report.
One new study conducted in KwaZulu-Natal, South Africa, reports that HIV was the single greatest risk factor for tuberculosis, and that 11 to 16 percent of healthcare workers in the region had HIV. Study author Carrie Tudor at the School of Nursing, Johns Hopkins University in Maryland, also found that where one worked in a health facility did not impact disease rates. Healthcare workers could be exposed either by diagnosed patients in a tuberculosis ward or undiagnosed patients or staff in other parts of the facility.
Renaud Boulanger at McGill University in Montreal, Canada, and colleagues note the range of ethical issues inherent in the epidemic, and their effects on healthcare workers whose very dedication to protecting the health of others exposes them to serious risks.
Need for vaccine, control measures, for front line health workers
About one-third of the global population is latently infected with the tuberculosis bacterium, and therefore at risk of developing active disease. Among healthcare workers, the proportion is even higher: 50 percent in India, 57 percent in Uganda, and 63 percent in Brazil, writes Mark Hatherill of SATVI.
Although many of these healthcare workers received the existing tuberculosis vaccine, Bacille Calmette-Guérin (BCG), as infants, the vaccine is only moderately effective in preventing severe tuberculosis in infants and young children—and it doesn’t adequately protect teens and adults, who are most at risk for developing and spreading the disease.
Hatherill notes that revaccination with BCG might help protect those relatively few healthcare workers who have not yet been exposed to tuberculosis. On the other hand, because BCG contains live bacteria, it could pose a danger to healthcare workers who are HIV positive and may not know their status.
“A new post-exposure tuberculosis vaccine offers the greatest potential for protection, especially given repeated occupational exposure to tuberculosis,” Hatherill said.
Progress is underway to develop such vaccines. One approach is to develop an inhaled vaccine, delivered into the lungs, where it would stimulate local immune cells. Another would activate immune responses in mucosal membranes to protect against infection by air-borne bacteria.
Yet any vaccination program would need to supplement, not replace, a rapid scale up of control measures. These include managerial oversight, environmental controls such as good ventilation, and personal protective equipment such as masks. Furthermore, Sabine Verkuijl at Columbia University and colleagues note in one of the studies that HIV counseling and testing and antiretroviral therapy could avert almost half of XDR tuberculosis in South Africa. While control measures often overemphasize personal protection, in reality, masks are rarely tested for proper fit and are too frequently unavailable.
Gilles van Cutsem, with Médecins Sans Frontières, and colleagues call for a paradigm shift in how care is delivered, moving from a centralized hospital-based approach to a decentralized approach across communities with high rates of disease. The authors note that centralized care in hospitals often results in long treatment delays, and that the number of patients with diagnosed MDR tuberculosis not initiated on treatment increased from 16 000 to 39 000 between 2012 and 2013, globally.
Complacency, lack of awareness, and stigma exacerbate risks, especially for young healthcare workers who can feel invincible. Verkuijl notes that in one study, almost one-third of workers in two South African hospitals did not feel particularly concerned about the possibility or consequences of developing active TB.
This general finding is borne out in three individual patient case histories, described by Arne von Delft, with the School of Public Health and Family Medicine at the University of Cape Town, and his co-authors.
In one, a husband and wife, both doctors, are infected with an MDR strain of the tuberculosis bacterium. In a second, a young medical student—sick, isolated and confused—receives a phone call conveying her diagnosis of MDR tuberculosis. Worried for her life, she recalls another medical student who tragically died from the disease. In the third, a doctor and mother is informed on a phone call that she has XDR tuberculosis. At the time she is informed, she is in a crowded shopping mall.
Their dilemmas are exacerbated by stigma, which presents high barriers to the utilization and delivery of health services, as patients fear being shamed or isolated. Edwin Wouters at the University of Antwerp, Belgium, and colleagues describe pioneering work to develop and test a range of scales measuring stigma, with the ultimate goal of overcoming these barriers.
“Without a strong healthcare workforce on the front line, this battle against tuberculosis cannot be won,” said von Delft and colleagues.
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Aeras is a nonprofit, global biotech developing new tuberculosis vaccines for the world, in partnership with other biotech, pharmaceutical, and academic organizations. Aeras has 90 employees from over 20 countries around the world, and has offices in the U.S., Africa, and Asia. Aeras receives funding from the Bill & Melinda Gates Foundation, the UK Department for International Development, the Global Health Initiative Technology Fund, and pharmaceutical organizations. Support also is received from the National Institute of Allergy and Infectious Diseases, U.S. National Institutes of Health, and other governments, as well as through partnerships and collaborations with universities and pharmaceutical companies.