By Ethan Covey
Supply chain disruptions hindering the availability of drugs used to treat tuberculosis delayed treatment initiations, changed regimens and restricted implementation of short-course regimens for both latent TB infection (LTBI) and active infection, according to a new report (MMWR Morb Mortal Wkly Rep 2024;72:1390-1391).
The study was conducted in California, which reports approximately one-fifth of all U.S.-based TB cases each year.
“TB cure relies on the use of effective medications that must be taken for several months,” an official at the California Department of Public Health (CDPH) told Infectious Disease Special Edition. “There is currently no vaccine available in the U.S. to prevent TB infection, and TB medications are also used as TB prevention.”
Shortages of TB drugs have been common in recent years, with the FDA declaring shortages of rifapentine in March 2020, rifampin in December 2021, and isoniazid (INH) during May 2023.
To assess the impact of these shortages, the CDPH and the California TB Controllers Association distributed an internet survey to TB controllers and program managers of all 61 of California’s TB programs. In the survey, representatives from the TB programs ranked the importance of addressing TB drug instability relative to other TB control priorities on a priority scale ranging from 1 (lowest) to 10 (highest).
With a response rate of 89%, ensuring a stable supply of TB drugs was ranked a level of 8.6 among all programs and 9.4 among those with high case counts.
Fifty of the California TB programs reported at least one case during 2016 through 2021. Of these, 64% experienced a delay in availability or unavailability of an oral first-line TB medication. These interruptions caused delays in initiations or temporary pauses in treatment of TB disease or LTBI among 37% of all programs and 55% of high case count programs.
They also resulted in permanent changes in the choice of drugs to treat TB disease or LTBI and in the duration of treatment for 33% of all programs and 65% of those with high case counts.
“This report helps to quantify TB medication access problems across California, the U.S. state with the largest TB burden,” said the CDPH spokesperson, who asked not to be identified. “It also identified the disruptions in care TB drug shortages can have on people affected by TB.”
The spokesperson added: “TB programs in California have engaged in longstanding efforts to mitigate the effects of TB drug shortages. Intensified mitigation strategies, such as the development of a statewide buffer supply of TB medications, may help to avoid treatment interruptions. Proactive solutions at the national level are also needed."
One question raised by this study is how the full impact of drug supply interruptions can be captured over time.
“Because the survey assessed the experience of TB programs over a single time period, it did not reflect the recurrence of TB drug interruptions,” the spokesperson said. “In addition, the impact to programs such as the significant time needed to track down alternatives when supplies are limited can affect other key activities, such as prevention efforts. Finally, the survey was conducted prior to the announcement of the INH shortage by FDA, and therefore the study probably underestimates the breadth of recent INH interruptions experienced in California.”
