Authored by: Venkat Rao
Yes. A recent study published in the latest issue of Lancet reports a remarkable finding of a 2021 nationwide Tuberculosis (TB) outbreak in the USA linked to a commercial bone graft product.
As a communicable disease, TB bacteria (Mycobacterium tuberculosis) in the normal course spreads from one person to the other, when a person infected with TB bacteria in the lungs or throat coughs, sneezes, speaks or sings, releasing the bacteria into the air and people in close proximity may breathe in these TB bacteria-laden air and become infected. This is the normal mode by which infection spreads from person-to-person.
The health security-relevant observation in the Lancet study is that an outbreak of TB in the United States was made possible through a transplanted tissue, a bone graft product, which contained live cells derived from a single diseased donor. As a result, the bone graft product became the source of TB in the bone graft-recipient patients.
In this fascinating report on how the bone graft product became the source for a 2021nationwide TB outbreak in the US, investigators reported of an 80-years old tissue donor with clinically manifested symptoms of TB as the source of bones procured and processed into 154 units of bone allograft product containing live cells (infected with TB bacteria), which was then distributed to 37 hospitals and ambulatory surgical centers in 20 US states between March 1 and April 2, 2021. During the three-month period ending June 2021, a total of 136 bone grafts were implanted into 113 recipients aged 24 to 87 years in 18 states, with some individuals receiving multiple bone graft units. Of these 113 recipients, 87 (or 77%) were subsequently diagnosed with microbiological and lung imaging evidence of TB disease. Eight of these recipients died 8-99 days post bone graft product implantation. All 105 living recipients were put on TB therapy around 69 days post-bone graft product implantation.
Why is this a Health Security Issue?
TB is a communicable disease that is a major global public health and health security challenge of the 21st century. With much of the media conversation centered on the COVID-19 pandemic and other sensational, but less prevalent diseases such as Ebola and Zika, the growing threat of TB in general and the multi-drug resistant strains of the disease remains unnoticed. With very few drugs currently available to treat the drug-resistant version of the disease, TB is regarded as the major global public health challenge of the 2n1st century. According to the 2021 WHO report, 5.8 million people were newly diagnosed with TB without a reliable estimate on the number of multidrug resistant TB.
According to CDC, 1.7 billion people were infected with TB bacteria, representing roughly 23% of the world’s population and TB remains the leading infectious disease killer claiming 1.5 million lives globally each year. A total of 7,860 TB cases were reported in the United States in 2021 alone, at the rate of 2.4 per 100,000 persons.
TB is a growing public health challenge in the United States and several new studies points to the multi-drug resistant TB endemic in certain communities within the US. According to a 2021 TB surveillance report, a total of 615 out of 45,209 TB cases were confirmed multi-drug resistant TB and, in most cases, due to disease transmission or reactivation.
However, in Africa and Asia, a much higher proportion of reported TB cases are multi-drug resistant version. For example, a recent East African surveillance study report nearly 4% of all newly diagnosed and 21% of reactivated (meaning, previously treated) cases were found to be multidrug resistant TB, which was attributed to several risk factors prevalent in the East African study population.
Remarkably, this is the first time a tissue donor-derived transmission of TB bacteria resulted in a nationwide outbreak of TB in the United States causing significant mortality and morbidity. The risk of transmission of dangerous infectious diseases through tissue transplant and other human tissue-derived products require additional substantial review of product biosafety and biosecurity by the national regulating authorities. Additionally, a better and more careful TB and other communicable pathogen screening procedure and sourcing biological materials is crucial to meet the biosafety standards for organ donors.
Developing world with a much larger TB disease burden and relatively limited public health capacities require a more stringent tissue donor safety assessment before products derived from such sources end up as a major contributor to TB disease outbreak. If the outbreak involves a multidrug resistant version of TB, prevalence of which is on the ascent, these public health agencies will face deleterious health security consequences both nationally and globally.