In November 2021, an outbreak of multidrug-resistant tuberculosis (TB) occurred in Kansas, involving multiple children who were born in the U.S. and became infected in the state. The outbreak lasted for a year and affected 13 people across four households in Kansas City. This article aims to critically analyze the outbreak, its implications, and the response by public health officials.
The CDC researchers who reported on the outbreak emphasize that it serves as a cautionary tale for low TB incidence jurisdictions. The outbreak challenged the assumption that sustained declines in TB incidence are assured. It highlights the ongoing need for identification and treatment of latent TB infections, as well as a swift and multifaceted public health response for each newly diagnosed TB case.
An Overview of the Outbreak
The outbreak involved seven adults and six children. Interestingly, while most of the adults were born outside the U.S. and had experienced a multidrug-resistant TB outbreak with the same genotype in their home countries, the majority of the children were U.S.-born. This indicates that the children acquired the infection locally within the community.
The Spread of Infections
The outbreak started with an infant who was hospitalized with pulmonary and meningeal TB. Further investigation revealed four latent infections and four active infections in the same household. The infective strain was resistant to all four first-line drugs. Subsequently, another case emerged in a young child living in a different household in the same apartment building. Members of the two families had close social contact, shared a car, and commuted together to the same workplace.
Connections to Other Households
The investigation identified two additional households with connections to the initial two households. Household C had two latent cases and two active cases, including a teenager who had spent time in both households. Household D had three adults with latent infections. This suggests that the outbreak spread beyond the primary households and had a significant impact on the community.
Public health officials conducted investigations among contacts, a school, and a workplace to contain the outbreak. Contacts underwent testing to detect TB infection. Individualized treatment regimens were established for each person based on their age and condition. Most adults received a 26-week treatment regimen of multiple drugs, while children aged 9-13 received a different combination of drugs. The length of treatment varied for each case, but by September 2023, 13 out of 14 patients had completed treatment.
Challenges in Treatment
The treatment of children presented a unique challenge as the drugs used had not been extensively studied in children aged <15 years. The FDA granted a compassionate use authorization for the use of delamanid, a multidrug-resistant TB medication used in Europe, in three children. This highlights the need for further research and development of treatment options specifically tailored for children with TB.
Monitoring and Future Implications
The patients diagnosed with latent TB infections were successfully treated, and no complications or disease development occurred. However, public health officials will continue to monitor all patients every 6 months for at least 2 years to ensure that the infection remains under control. This demonstrates the importance of long-term surveillance and follow-up in managing TB outbreaks.
Genetic Analysis and Source of Infection
Genetic analysis of the TB isolates revealed that they were very similar, with only minimal differences. This finding supported the hypothesis that the outbreak was locally transmitted within the social setting of the affected families. Furthermore, the analysis showed a genetic link to previous outbreaks in other regions, indicating that at least some of the adults had been infected overseas and experienced disease progression after moving to Kansas.
The multidrug-resistant TB outbreak in Kansas serves as a cautionary tale and a reminder that sustained declines in TB incidence are not guaranteed. It highlights the importance of ongoing identification and treatment of latent TB infections and the need for a swift and multifaceted public health response in each newly diagnosed TB case. The outbreak also underscores the challenges in treating children with TB and the need for further research in this area. Continued monitoring and surveillance are crucial to ensure the long-term control of TB and to prevent future outbreaks.
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