Persons who use tobacco or alcohol 40,41 , illegal drugs, including injection drugs and crack cocaine 42—47 , might also be at increased risk for infection and disease. However, because of multiple other potential risk factors that commonly occur among such persons, use of these substances has been difficult to identify as separate risk factors.
Health-care settings should be particularly aware of the need for preventing transmission of M. Persons infected with HIV who are already severely immunocompromised and who become newly infected with M. Because the risk for disease is particularly high among HIV-infected persons with M. Vaccination with BCG probably does not affect the risk for infection after exposure, but it might decrease the risk for progression from infection with M. Exposure to TB in small, enclosed spaces. Inadequate local or general ventilation that results in insufficient dilution or removal of infectious droplet nuclei.
Recirculation of air containing infectious droplet nuclei. Inadequate cleaning and disinfection of medical equipment. Improper procedures for handling specimens. The magnitude of the risk varies by setting, occupational group, prevalence of TB in the community, patient population, and effectiveness of TB infection-control measures.
Health-care—associated transmission of M. Factors contributing to these outbreaks included delayed diagnosis of TB disease, delayed initiation and inadequate airborne precautions, lapses in AII practices and precautions for cough-inducing and aerosol-generating procedures, and lack of adequate respiratory protection.
Multiple studies suggest that the decline in health-care—associated transmission observed in specific institutions is associated with the rigorous implementation of infection-control measures 11,12,18—20,23,95— Because various interventions were implemented simultaneously, the effectiveness of each intervention could not be determined.
After the release of the CDC infection-control guidelines, increased implementation of recommended infection-control measures occurred and was documented in multiple national surveys 13,15,98, A survey of New York City hospitals with high caseloads of TB disease indicated 1 a decrease in the time that patients with TB disease spent in EDs before being transferred to a hospital room, 2 an increase in the proportion of patients initially placed in AII rooms, 3 an increase in the proportion of patients started on recommended antituberculosis treatment and reported to the local or state health department, and 4 an increase in the use of recommended respiratory protection and environmental controls Reports of increased implementation of recommended TB infection controls combined with decreased reports of outbreaks of TB disease in health-care settings suggest that the recommended controls are effective in reducing and preventing health-care—associated transmission of M.
Less information is available regarding the implementation of CDC-recommended TB infection-control measures in settings other than hospitals. One study identified major barriers to implementation that contribute to the costs of a TST program in health departments and hospitals, including personnel costs, HCWs' time off from work for TST administration and reading, and training and education of HCWs Outbreaks have occurred in outpatient settings i.
CDC-recommended TB infection-control measures are implemented in correctional facilities, and certain variations might relate to resources, expertise, and oversight — In the United States, the problem of MDR TB, which was amplified by health-care—associated transmission, has been substantially reduced by the use of standardized antituberculosis treatment regimens in the initial phase of therapy, rapid drug-susceptibility testing, directly observed therapy DOT , and improved infection-control practices 1.
DOT is an adherence-enhancing strategy in which an HCW or other specially trained health professional watches a patient swallow each dose of medication and records the dates that the administration was observed. All health-care settings need a TB infection-control program designed to ensure prompt detection, airborne precautions, and treatment of persons who have suspected or confirmed TB disease or prompt referral of persons who have suspected TB disease for settings in which persons with TB disease are not expected to be encountered.
Such a program is based on a three-level hierarchy of controls, including administrative, environmental, and respiratory protection 86,, Administrative Controls The first and most important level of TB controls is the use of administrative measures to reduce the risk for exposure to persons who might have TB disease.
Administrative controls consist of the following activities: HCWs with TB disease should be allowed to return to work when they 1 have had three negative AFB sputum smear results — collected 8—24 hours apart, with at least one being an early morning specimen because respiratory secretions pool overnight; and 2 have responded to antituberculosis treatment that will probably be effective based on susceptibility results.
Consideration should also be given to the type of setting and the potential risk to patients e. Environmental Controls The second level of the hierarchy is the use of environmental controls to prevent the spread and reduce the concentration of infectious droplet nuclei in ambient air. Primary environmental controls consist of controlling the source of infection by using local exhaust ventilation e. Secondary environmental controls consist of controlling the airflow to prevent contamination of air in areas adjacent to the source AII rooms and cleaning the air by using high efficiency particulate air HEPA filtration or UVGI.
Respiratory-Protection Controls The first two control levels minimize the number of areas in which exposure to M. These control levels also reduce, but do not eliminate, the risk for exposure in the limited areas in which exposure can still occur. Because persons entering these areas might be exposed to M.
Use of respiratory protection can further reduce risk for exposure of HCWs to infectious droplet nuclei that have been expelled into the air from a patient with infectious TB disease see Respiratory Protection.
The following measures can be taken to reduce the risk for exposure: Implementation of the TB infection-control guidelines described in this document is essential for preventing and controlling transmission of M. Additional information is at http: Recommendations for Preventing Transmission of M. The specific details of the TB infection-control program will differ, depending on whether patients with suspected or confirmed TB disease might be encountered in the setting or whether patients with suspected or confirmed TB disease will be transferred to another health-care setting.
Administrators making this distinction should obtain medical and epidemiologic consultation from state and local health departments. Every setting in which services are provided to persons who have suspected or confirmed infectious TB disease, including laboratories and nontraditional facility-based settings, should have a TB infection-control plan.
The following steps should be taken to establish a TB infection-control program in these settings: Assign supervisory responsibility for the TB infection-control program to a designated person or group with expertise in LTBI and TB disease, infection control, occupational health, environmental controls, and respiratory protection.
Give the supervisor or supervisory body the support and authority to conduct a TB risk assessment, implement and enforce TB infection-control policies, and ensure recommended training and education of HCWs. Develop a written TB infection-control plan that outlines a protocol for the prompt recognition and initiation of airborne precautions of persons with suspected or confirmed TB disease, and update it annually. Conduct a problem evaluation see Problem Evaluation if a case of suspected or confirmed TB disease is not promptly recognized and appropriate airborne precautions not initiated, or if administrative, environmental, or respiratory-protection controls fail.
Perform a contact investigation in collaboration with the local or state health department if health-care—associated transmission of M. Implement and monitor corrective action. Collaborate with the local or state health department to develop administrative controls consisting of the risk assessment, the written TB infection-control plan, management of patients with suspected or confirmed TB disease, training and education of HCWs, screening and evaluation of HCWs, problem evaluation, and coordination.
Implement a respiratory-protection program. Create a plan for accepting patients who have suspected or confirmed TB disease if they are transferred from another setting.
Assign responsibility for the TB infection-control program to appropriate personnel. Develop a written TB infection-control plan that outlines a protocol for the prompt recognition and transfer of persons who have suspected or confirmed TB disease to another health-care setting.
The plan should indicate procedures to follow to separate persons with suspected or confirmed infectious TB disease from other persons in the setting until the time of transfer.
Evaluate the plan annually, if possible, to ensure that the setting remains one in which persons who have suspected or confirmed TB disease are not encountered and that they are promptly transferred. Conduct a problem evaluation see Problem Evaluation if a case of suspected or confirmed TB disease is not promptly recognized, separated from others, and transferred.
Perform an investigation in collaboration with the local or state health department if health-care—associated transmission of M. Collaborate with the local or state health department to develop administrative controls consisting of the risk assessment and the written TB infection-control plan. TB Risk Assessment Every health-care setting should conduct initial and ongoing evaluations of the risk for transmission of M.
The TB risk assessment determines the types of administrative, environmental, and respiratory-protection controls needed for a setting and serves as an ongoing evaluation tool of the quality of TB infection control and for the identification of needed improvements in infection-control measures. Part of the risk assessment is similar to a program review that is conducted by the local TB-control program This worksheet frequently does not specify values for acceptable performance indicators because of the lack of scientific data.
Review the community profile of TB disease in collaboration with the state or local health department. Consult the local or state TB-control program to obtain epidemiologic surveillance data necessary to conduct a TB risk assessment for the health-care setting. Review the number of patients with suspected or confirmed TB disease who have been encountered in the setting during at least the previous 5 years.
Determine if persons with unrecognized TB disease have been admitted to or were encountered in the setting during the previous 5 years. Determine which HCWs need to be included in a TB screening program and the frequency of screening based on risk classification Appendix C. Ensure the prompt recognition and evaluation of suspected episodes of health-care—associated transmission of M.
Identify areas in the setting with an increased risk for health-care—associated transmission of M. Assess the number of AII rooms needed for the setting. The risk classification for the setting should help to make this determination, depending on the number of TB patients examined.
At least one AII room is needed for settings in which TB patients stay while they are being treated, and additional AII rooms might be needed, depending on the magnitude of patient-days of cases of suspected or confirmed TB disease.
Additional AII rooms might be considered if options are limited for transferring patients with suspected or confirmed TB disease to other settings with AII rooms. Determine which HCWs need to be included in the respiratory-protection program. Conduct periodic reassessments annually, if possible to ensure — proper implementation of the TB infection-control plan, — prompt detection and evaluation of suspected TB cases, — prompt initiation of airborne precautions of suspected infectious TB cases, — recommended medical management of patients with suspected or confirmed TB disease 31 , — functional environmental controls, — implementation of the respiratory-protection program, and — ongoing HCW training and education regarding TB.
Recognize and correct lapses in infection control. Review the community profile of TB disease in collaboration with the local or state health department. Determine if persons with unrecognized TB disease were encountered in the setting during the previous 5 years.
Determine the types of environmental controls that are currently in place, and determine if any are needed in the setting Appendices A and D. Document procedures that ensure the prompt recognition and evaluation of suspected episodes of health-care—associated transmission of M.
Conduct periodic reassessments annually, if possible to ensure 1 proper implementation of the TB infection-control plan; 2 prompt detection and evaluation of suspected TB cases; 3 prompt initiation of airborne precautions of suspected infectious TB cases before transfer; 4 prompt transfer of suspected infectious TB cases; 5 proper functioning of environmental controls, as applicable; and 6 ongoing TB training and education for HCWs.
A risk classification usually should be determined for the entire setting. However, in certain settings e. Examples of assigning risk classifications have been provided see Risk Classification Examples. TB Screening Risk Classifications The three TB screening risk classifications are low risk, medium risk, and potential ongoing transmission.
The classification of low risk should be applied to settings in which persons with TB disease are not expected to be encountered, and, therefore, exposure to M. This classification should also be applied to HCWs who will never be exposed to persons with TB disease or to clinical specimens that might contain M. The classification of medium risk should be applied to settings in which the risk assessment has determined that HCWs will or will possibly be exposed to persons with TB disease or to clinical specimens that might contain M.
The classification of potential ongoing transmission should be temporarily applied to any setting or group of HCWs if evidence suggestive of person-to-person e. Evidence of person-to-person transmission of M. If uncertainty exists regarding whether to classify a setting as low risk or medium risk, the setting typically should be classified as medium risk.
After baseline testing for infection with M. HCWs with a baseline positive or newly positive test result for M. Repeat radiographs are not needed unless symptoms or signs of TB disease develop or unless recommended by a clinician 39 , Instead of participating in serial testing, HCWs should receive a symptom screen annually.