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Education Materials > Publications > Self-Study Modules on TB > Module 5 > Infection Control

Self-Study Modules on Tuberculosis

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Module 5: Infectiousness and Infection Control

Infection Control

Where Can TB Be Spread?

TB is a communicable disease. It can be spread in many places, such as homes or worksites. On average, about 30% of people who spend a lot of time with someone who has infectious TB disease (close contacts) become infected with M. tuberculosis. However, TB patients vary in their infectiousness; some infect most or all their close contacts, whereas others infect few or none of their contacts.

TB can also be transmitted in health care facilities, such as hospitals and clinics. TB is most likely to be transmitted when health care workers and patients come in contact with patients who have unsuspected TB disease, who are not receiving adequate treatment, and who have not been isolated from others. Several recent outbreaks of TB in health care facilities, including outbreaks of multidrug-resistant TB, have heightened concern about the spread of TB in these facilities. The transmission of TB to HIV-infected people is of particular concern because these persons are at high risk of developing TB disease if infected. All health care facilities should take measures to prevent the spread of TB.

What Are the Parts of an Effective Infection Control Program?

The main goal of an infection control program is to detect TB disease early and to promptly isolate and treat people who have TB disease. The infection control program should involve three types of controls:
  • Administrative controls
  • Engineering controls
  • Personal respiratory protection

Administrative controls. Administrative controls mean establishing and following guidelines for

  • Promptly detecting patients who have TB disease
  • Placing these patients in an area away from other patients and giving them a diagnostic evaluation
  • Treating patients who are likely to have TB disease
Other administrative control measures include
  • Making sure that health care workers are following guidelines for preventing the spread of TB
  • Educating, training, and counseling health care workers about TB
  • Screening health care workers for TB infection and disease
To detect patients who have TB disease as soon as possible, clinicians and other health care workers should suspect TB disease in a patient who has any of these symptoms:
  • A persistent cough
  • Bloody sputum
  • Weight loss or loss of appetite
  • Fever
  • Night sweats
In areas where TB is very common, staff of local health care facilities should be especially alert for TB. Health care workers who admit patients to the facility should be trained to ask appropriate questions to help detect patients who have signs or symptoms of TB disease.

Patients who have signs or symptoms of TB disease should be placed in an area away from other patients (preferably in a TB isolation room) and promptly given a diagnostic evaluation. These patients should be given a surgical mask (Figure 5.1) and instructed to keep it on. They should also be given tissues and asked to cover their nose and mouth when coughing or sneezing, even when in an area away from others.

Figure 5.1 TB patient wearing a surgical mask. This is a picture of a TB patient wearing a surgical mask.

In hospitals and other inpatient settings, patients known to have TB disease or suspected of having TB disease should be placed in a special TB isolation room right away. TB isolation rooms are rooms in the facility that have special characteristics to prevent the spread of droplet nuclei expelled by a TB patient. One characteristic of TB isolation rooms is that they are at negative pressure relative to other parts of the facility. Negative pressure means that air flows from the corridors into the isolation room. This way, contaminated air cannot escape from the isolation room to other parts of the facility. Air from the isolation room can be exhausted directly to the outdoors, where any infectious droplet nuclei will be diluted in the outdoor air and killed by the sunlight. Alternatively, the air can be passed through a special filter that removes all of the droplet nuclei before the air is returned to the general circulation (see HEPA filters, in the Engineering Controls Section). The room should have at least six air changes per hour. The door must be kept closed in order to maintain negative pressure, and the room must be checked periodically to make sure that it remains at negative pressure.

Patients suspected of having TB disease should be given a diagnostic evaluation as soon as possible. This means a medical history, a tuberculin skin test, a chest x-ray, and the collection of specimens for a bacteriologic examination (see Module 3, Diagnosis of Tuberculosis Infection and Disease). It is important that laboratories use the most rapid diagnostic methods available. In outpatient settings where a diagnostic evaluation cannot be completed, patients who have symptoms of TB should be referred to a facility capable of doing the evaluation.

Patients who are likely to have TB should start appropriate treatment at once.

Patients should be educated about the transmission of TB, the reason for TB isolation, and the importance of staying in their room. Every effort should be made to help the patient follow the isolation policy including the use of incentives, such as providing telephones or televisions or allowing special dietary requests. As few people as possible should be allowed to enter the TB isolation room, and anyone entering should wear respiratory protection (see Personal Respiratory Protection).

Training and education. All health care workers should be educated about the basic concepts of TB transmission and pathogenesis, infection control practices, the signs and symptoms of TB, and the importance of participating in the skin testing program for health care workers.

TB screening for health care workers. Health care workers who may be exposed to TB should be included in a TB screening and prevention program. This means two-step tuberculin skin testing upon employment and at least once a year thereafter. Any worker who develops symptoms of TB disease or whose tuberculin skin test reaction converts to positive should be evaluated promptly.

Study Questions 5.4-5.7

5.4 In what circumstances is TB most likely to be transmitted in health care facilities?

5.5 What is the main goal of an infection control program? What three types of controls should this program involve?

5.6. What would make a health care worker suspect that a patient has TB disease?

5.7 What should be done when a health care worker suspects that a patient has TB disease?



Study Questions 5.8-5.9

5.8 What is a TB isolation room? What are the important characteristics of an isolation room?

5.9 How often should health care workers who may be exposed to TB be tuberculin skin tested?



Case Study 5.2

You are checking patients into the TB clinic. An elderly man comes to the desk and says he was told to come and get checked because one of his friends has TB. You notice that he looks sick and is coughing frequently. The waiting room is full of patients, and you know it will probably be more than an hour before the physician can see him.

  • What should you do?


Engineering controls. Three types of engineering controls are used to prevent the transmission of TB in health care facilities: ventilation, high-efficiency particulate air (HEPA) filtration, and ultraviolet germicidal irradiation. In isolation rooms, ventilation systems are necessary to maintain negative pressure and to exhaust the air properly. These systems can also be designed to minimize the spread of TB in other areas of the health care facility. HEPA filters are special filters that can be used in ventilation systems to help remove droplet nuclei from the air. Ultraviolet germicidal irradiation (UVGI), or the use of special lamps that give off ultraviolet light, is used to kill the tubercle bacilli contained in droplet nuclei. However, exposure to ultraviolet light can be harmful to the skin and eyes of humans, so the lamps must be installed in the upper part of rooms or corridors or placed in exhaust ducts. HEPA filters and UVGI should be used in conjunction with other infection control measures.

Personal respiratory protection. In some settings, administrative and engineering controls may not fully protect health care workers from infectious droplet nuclei. These settings include

  • TB isolation rooms
  • Rooms where cough-inducing procedures are done
  • Ambulances and other vehicles transporting infectious TB patients
  • The homes of infectious TB patients

Health care workers should use personal respirators, or special masks designed to filter out droplet nuclei, in these settings (Figures 5.2 and 5.3). Health care workers should be taught how and when to use personal respirators.

Figures 5.2 and 5.3 Health care worker wearing a personal respirator. The personal respirator in these photographs is specially designed to filter out droplet nuclei. This is a picture of a health care worker wearing a personal respirator which are used to filter out droplet nuclei.

Cough-inducing procedures. Cough-inducing procedures should be done in special isolation rooms or booths. This will prevent any droplet nuclei that are expelled during the procedure from reaching other parts of the facility. Some examples of cough-inducing procedures are sputum induction, bronchoscopy, and the administration of aerosolized medications (such as pentamidine, which is given to patients with HIV infection to prevent Pneumocystis carinii pneumonia).

Study Questions 5.10-5.12

5.10. How do ventilation systems help prevent the spread of TB?

5.11. Give four examples of settings where personal respirators should be used.

5.12. Where should sputum induction, bronchoscopy, and other cough-inducing procedures be done?


What Is the Role of the Health Department in Infection Control?

The health department should work closely with health care facilities to help them report confirmed or suspected TB cases as quickly as possible. When the health department receives a report of a TB case or suspected case, it should begin a contact investigation. Also, the health department and the health care facilities should work together to make sure there is a plan for TB patients to receive follow-up care after they are discharged. Finally, the health department should be able to help health care facilities with screening, surveillance, outbreak investigations, and other aspects of a TB infection control program.

Infection Control in Residential Facilities

All residential facilities where TB patients receive care should establish and follow an infection control program. These residential facilities may include nursing homes, correctional facilities, homeless shelters, drug treatment centers, and other places. As in health care facilities, the main goal of the infection control program should be to detect TB disease early and arrange for the isolation and treatment of suspected TB patients. CDC has published guidelines for controlling TB in certain types of residential facilities (see Additional Reading).

Infection Control in the Home

Patients who are suspected of having infectious TB are frequently sent home after starting treatment, even though they may still be infectious. This is because people with TB disease are most likely to transmit TB to members of their household before TB has been diagnosed and treatment has started. However, TB patients and members of their household can take steps to prevent the spread of TB in their home. For example, TB patients should be instructed to cover their mouth and nose with a tissue when coughing or sneezing.

Health care workers who visit TB patients at home should take these precautions to protect themselves from the spread of TB:

  • Instruct patients to cover their mouth and nose with a tissue when coughing or sneezing
  • Wear a personal respirator when visiting the home of an infectious TB patient or when transporting an infectious TB patient in a vehicle
  • When it is necessary to collect a sputum specimen in the home, collect the specimen in a well-ventilated area, away from other household members; if possible, the specimen should be collected outdoors
  • Participate in a TB screening and prevention program

Study Questions 5.13-5.14

5.13. How can the health department help health care facilities in preventing the spread of TB?

5.14. What precautions should a health care worker take when visiting the home of a TB patient who may be infectious?



Case Study 5.3

You are sent to deliver directly observed therapy to a woman who started treatment last week for suspected pulmonary TB. Her sputum smear results are not back yet. You are asked to collect another sputum specimen while you are at the woman's home.

  • What precautions should you take?



Released October 2008
Centers for Disease Control and Prevention
National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention
Division of Tuberculosis Elimination -

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