15.1 Goal and Objective of TB Infection Prevention Control

The administrative controls include decisions, policies and procedures aimed at reducing generation & transmission of and exposure to infectious droplet nuclei. These include measures for prompt identification and treatment of infectious cases and are hence regarded as the first line of defence in terms of TB infection prevention and control.

TB IPC requires action at national and sub-national level to provide managerial direction, and at health facility level to implement TB IPC measures. The set of IPC related recommendations and policies at the national and sub-national level are necessary to facilitate implementation of TB IPC in health-care facilities, congregate settings and households. The range of activities includes:

• Identifying (or creating) and strengthening a national coordinating body to spearhead this
• Preparing and adopting a national Strategy and Guidelines (including recommendations on HR strengthening)
• Carrying out risk assessments using standardised tools to assess the TB IPC related baseline situation at all levels of health care and congregate settings
• Comprehensive planning and budgeting
• Systematic surveillance of TB disease among health workers
• Appropriate designing, construction, renovation, use and maintenance of TB IPC equipment at health care facilities
• Targeted ACSM (SBCC)
• Routine and systematic monitoring and evaluation of the TB IPC measures.

Patients triage

All patients, upon entry into the health facility, should be promptly screened for cough by a member of the medical staff. Where possible, patients with cough over two weeks should be sent to a separate and well ventilated waiting room. All patients with current cough of any duration should receive tissues or face masks, and they should be counselled to keep their nose and mouth covered at all times. The clinical as well as laboratory investigations of all such patients should be prioritized and fast tracked to minimize their time inside the health facility.

Patient, visitors and attendants' flow

• Encourage patients and attendants to spend as much time as possible outdoors (if the weather permits) or in areas that are well ventilated (open on three or four sides).
• Restrict access to TB wards by using prominent signages on entry doors.
• Limit visitation duration, particularly for contagious patients.
• Encourage visits outside the building and in the open, especially for contagious patients.
• Have visiting areas clearly demarcated with signage. The signage should also include information on respiratory hygiene and encourage everyone visiting the high risk settings to follow those.
• Before any visit, the nurse/ health workers should provide counselling on risk of transmission, the usage of respirators if caregivers need to enter the high risk areas such as Labs or clinics were diagnosis of TB is being undertaken and indoor units housing smear-positive, drug-resistant TB (DR-TB) and smear positive previously treated patients
• The patient flow in the health facilities should be designed in such a manner that presumptive or confirmed TB patients do not come in to contact with other patients visiting the hospital to avoid unnecessary exposure and cross infections.

Segregation of hospitalized patients

Hospitalisation should be avoided unless absolutely necessary. Presumptive or confirmed TB and DR TB patients should be physically separated from other patients.

Immediate initiation of treatment for diagnosed patients

All diagnosed TB patients should be immediately initiated on the appropriate treatment to reduce the bacteria load and minimise chances of transmission.

TB IPC training

All healthcare personnel should receive initial training on TB transmission, information on high-risk areas in the facility and on protective measures. Continuing education should be offered annually. The training should also include counselling of patients, visitors and attendants about the risk of TB transmission and infection prevention measures (cough etiquette, use of masks and respirators etc.)

Environmental controls is regarded as the second line of defence. These set of measures aim at reducing the concentration of infectious particles (droplet nuclei) in the air.

Ventilation:

Ventilation (replacement of inside air with outside air) is the most effective means for reducing the concentration of M. tuberculosis in the air, and as a result, the risk of transmission. The WHO recommends that in areas where TB transmission might occur, a minimum ventilation rate of 12 air changes per hour (ACH) should be achieved.

Effective ventilation can be obtained by natural (assisted or not) or mechanical means

• Natural ventilation: Natural ventilation, especially cross-ventilation (windows/doors in opposite sides of the room), has the best cost-effective ratio. It should be done with the windows and outside doors open (as much as weather conditions permit). Inside doors should be closed so that the flow of air is directed outside and not toward the corridors. Create shady spaces so that patients, attendants and visitors can stay outside during the day.
• Mechanical ventilation: When natural ventilation cannot reach adequate rates, centralized mechanical ventilation should be considered in some settings, such as in colder climates. Centralised mechanical ventilation relies on the use of mechanical equipment to maintain an air pressure difference between two areas in order to draw air into a room and vent it to the outside. It requires uninterrupted electricity and continuous & meticulous maintenance, which renders it costly and difficult to implement and operate.

Architectural considerations

Airborne infection control should be always considered during the planning/construction stages of new health facilities and those being modified. It is important to achieve the following:

• Building layout and design with maximised natural ventilation (assisted or not) and sunlight. Waiting areas should be open on three sides. Design of TB wards should avoid internal hallways with doors from the rooms and wards opening into them. Instead, doors should open to outer hallways that are open to outside air (this may not be feasible in cold climates).
• Specific areas (open air, sputum collection booth, etc.) should be reserved for procedures with a high risk of M. tuberculosis transmission (e.g. sputum collection, sputum induction, etc.).
• Allow patient flow that reduces exposure of patients at risk to patients that are infectious (e.g. separate waiting rooms for different cohorts, one patient per room in a hospital). If designing a new TB ward, incorporate plenty of single rooms or at least small rooms with 2 to 4 beds placed at least 3 feet apart for easier separation of the different cohorts of patients. General hospitals should also have isolation rooms available for TB suspects and contagious patients.

Ultra-violet germicidal irradiation

Ultra-violet germicidal irradiation (UVGI) lamps may be used when adequate ventilation cannot be achieved in high-risk areas. When properly installed, designed, maintained and operated, an UVGI system, in addition to 6-12 ACH ventilation, could be the equivalent of 10-25 ACH.

• Main requirements and constraints in UV lamps usage include:
  • Expertise in installation and testing
  • Rigorous monitoring and maintenance
  • Electricity, relative humidity less than 70%, good air mixing.
• Potential hazards include: Transient eye and skin injuries from overexposure and mercury poisoning (broken or mishandled lamp).

Areas requiring specific measures

• Sputum collection areas: Wherever feasible, these areas must be located outside in the open or in well ventilated rooms so that any bacilli containing aerosol can be quickly dispersed. Sputum collection should not be done in closed areas such as toilets and in ill-ventilated rooms to avoid build up of infectious particles in the air.
• Laboratory: All laboratories should undergo a risk assessment, and IC measures should be adapted accordingly. In any case, only authorized persons should be allowed access to the Lab. The use of ventilated workstation is strongly recommended for sample processing and smear preparation (microscopy and GeneXpert). In laboratories where culture is carried out, Class II (preferably Type A2) Biological Safety Cabinets (BSC), must be used.
• Laboratories must have easy to clean working surfaces (avoid wood) to allow proper disinfection. In the absence of mechanical ventilation, the Labs should have large windows to let in sunlight and allow natural ventilation. Water-filters should be used to avoid contamination by saprophyte mycobacteria that are sometimes present in the water.

Personal respiratory protection is the third line of defence especially aimed at protecting heath care workers (HCWs). This refers to items specifically used to protect the health care providers, the patients and the community from exposure to droplet or airborne infection.

Respirators

A respirator is a personal protective equipment that, when worn correctly, has the capacity to filter particles and prevent the inhalation of infectious droplet nuclei by the person who wears it correctly. Exposed staff: Staff must wear a respirator, regardless if they are the caregiver or not. Respirators should be worn:

• When in contact with contagious patients (suspect or confirmed TB case)
• When collecting sputum samples
• When collecting and disposing of sputum containers
• In areas where droplet nuclei could be present (i.e. a room that has been occupied by a TB case, prior to the time required for air cleaning).

Visitors/attendants: Visitors and attendants must wear a respirator when entering a contagious TB patient’s room.

Face or surgical masks

Face masks are medical devices that prevent patients from spreading infectious droplets when talking, coughing or sneezing. They should be worn by contagious patients (suspect or confirmed) when they leave their rooms to go to another department or any other enclosed area. They should not be worn when the patient is alone in his/her room and outdoors.