Download Environmental measures to prevent TB transmission in resource

Environmental measures
to prevent TB transmission
in resource-limited settings
having a high TB-HIV burden
A compilation of recommendations and discussions from a Regional Workshop
in Cape Town, South Africa
13-16 February 2011
ACKNOWLEDGEMENTS
The workshop was organized and funded by MSF South Africa, with additional organizational
support provided by the South African Medical Unit (SAMU) of Operational Centre Brussels (MSFOCB).
MSF staff from field projects and headquarter levels of four different Operational Centres were
represented at the workshop, as were a number of partner organizations. Many thanks to the
following external participants who were able to share their important experience on environmental
measures to prevent transmission of tuberculosis (TB):

Virginia De Azevedo, Khayelitsha Sub-district Manager, Cape Town City Health
Department

Cornel Badenhorst, C M 3 Consulting Engineers

Rod Escombe, Honorary Research Fellow, Imperial College London

Simone Le Fevre, Cooke Le Fevre Architects and Urban Designers, University Of Cape
Town Department of Architecture (Faculty)

Shannon Maree, Senior Mechanical Engineer, City of Cape Town

Shaheen Mehtar, Head of Academic Unit for Infection Prevention and Control at Tygerberg
Hospital, Professor at University of Stellenbosch
3
TABLE OF CONTENTS
Page
I.
List of Abbreviations
5
II.
Workshop Objectives and Expected Outcomes
6
III.
Recommendations
7
A. Key recommendations
7
B. General recommendations
7
C. Technical recommendations
9
D. Specific technical recommendations
10
E. Summary table of proposed specifications
12
IV.
Background
13
V.
Summary of Presentations and Discussions
15

Medical perspective
15

Organizing prevention and control of TB
17

The role of construction logisticians
18

The role of the WHS department
18

Environmental TBIC measures
19
o Natural ventilation
20
o Mechanical ventilation
22
o UVGI
22

Building designs to ensure adequate TBIC in hospital settings
23

Laboratory design and layout
25

Architecture and infection control
26

Challenges in the field
27

Possible solutions
28
VI.
Areas that require further Operational Research
29
VII.
Conclusion
30
Appendix 1: Algorithm to adapt plans of existing buildings
31
Appendix 2: Possible PHC clinic floor plans
32
Appendix 3: Analysis of equipment for environmental control
33
Appendix 4: List of Participants
34
4
I.
LIST OF ABBREVIATIONS
AC
Air conditioning
ACH
Air changes per hour
DR-TB
Drug-resistant TB
DS-TB
Drug-sensitive TB
EPTB
Extrapulmonary TB (i.e. active TB outside the lungs)
HCW
Healthcare worker
HEPA filter
High efficiency particulate air filter
HIV
Human immunodeficiency virus
HWB
Hand-washing basin
ICC
Infection control committee
IPC
Infection prevention and control
MDR
Multidrug-resistant TB
MoH
Ministry of Health
MSF
Médecins Sans Frontières
PHC
Primary healthcare
PLHIV
People living with HIV
PPE
Personal protective equipment
PTB
Pulmonary TB (i.e. active TB in the lungs)
RH
Relative humidity
TB
Tuberculosis
TBIC
Tuberculosis infection control
UVGI
Ultraviolet germicidal irradiation
WHO
World Health Organization
WHS
Water-Hygiene-Sanitation
XDR
Extensively drug-resistant TB
5
II.
WORKSHOP OBJECTIVES AND EXPECTED OUTCOMES
The objectives of the workshop were to:
i.
Exchange ideas with all stakeholders who starve to find solutions to prevent transmission of
TB (and other airborne diseases) in health facilities in resource-limited settings
ii.
Define and transmit clear messages to MSF Operations Department related to environmental
aspects of TB Infection Control
iii.
Strengthen existing documentation and support (including briefings and trainings) offered to
MSF staff involved in environmental aspects of TB Infection Control
iv.
Identify areas for potential operational research
The expected outcomes of the workshop were to:

Sharing common challenges related to environmental aspects of TB Infection Control and
experience in potential solutions for different settings


Create a list of internal recommendations for MSF projects having a high TB-HIV burden:
o
related to environmental measures that prevent transmission of TB
o
relevant for resource-limited settings
o
which can represent a ‘minimum standard’ that can be expected in our projects
o
including principles that should be followed
Clarify roles and responsibilities in the development and implementation of environmental TBIC
measures

List areas in which operational research is needed
6
III.
RECOMMENDATIONS
III.A. Key recommendations from the workshop

In resource-limited settings, the simplest environmental TB infection control (TBIC) measures
that maximize natural ventilation should be considered first (e.g. use of cross-ventilation, whirlybirds, etc).

All TBIC measures should be implemented throughout healthcare facilities located in settings
having a high TB-HIV burden.

TBIC environmental measures should be considered during the design of new buildings and
whenever modifications are planned for existing facilities.

MSF HQs need to invest more in TBIC, both financially and in terms of human resources,
including:
o Trainings for relevant staff
o Making tools available to the field (e.g. to measure ventilation)
o Introduction of a regional TBIC support position
o Production of evidence related to different TBIC measures through operational research
III.B. General recommendations

MSF has a responsibility to minimize the risk of TB exposure by patients visiting healthcare
facilities that we support in high TB-HIV burden settings, along the lines of the basic healthcare
motto: “firstly, do no harm”.
o We also have a similar responsibility to prevent TB infection in HCWs (and other staff)
providing health services, especially since there are already too few HCWs in high TBHIV burden settings.
o Cases of TB infection amongst HCWs (national and international staff) need to be
monitored, documented, and reported both within MSF (to the TB-HIV Adviser) and to
the appropriate health authorities.

In countries with high HIV and TB burdens, all healthcare facilities should be considered high
risk areas for TB transmission.
7
o Since it is coughing, usually undiagnosed, people with active PTB that represent the
greatest threat of TB transmission, appropriate TBIC measures should be implemented
throughout healthcare facilities.
o Infection control committees should be set up in each facility, and be involved in
important decisions related to the 3 groups of TBIC measures (administrative,
environmental, and personal protection).

Since there are almost always weaknesses related to implementation of administrative and
personal protective TBIC measures in places where MSF works, we should try to implement
‘fool-proof’ environmental measures in the design and renovation of health care facilities,
especially those that maximize natural ventilation.
o Environmental measures alone, however, are never enough!
o Environmental control strategies should be closely linked to patient flow in healthcare
facilities.

There is a need to provide airborne infection control training so that all relevant staff better
understand issues related to IC: medical, logistical, construction, architectural, coordination and
those at the HQ level.
o There are already many TBIC guidelines available but these need to be adapted to the
resource-limited settings that MSF supports.
o Full-time IC Practitioners can play an essential role in many projects. They should be
considered for introduction in relevant projects and given authority, training and adapted
equipment.

Better communication/collaboration should be encouraged between logs/constructors/architects
and relevant medical people at a number of different levels within MSF (from project to HQ) to
ensure optimal TBIC in healthcare facilities that we support.
o The medical team should take the lead in carrying out TBIC assessments in order to
identify the needs in each MSF project.
o Medical teams should provide feedback from patients and HCWs related to attempts to
improve TBIC.

Airborne infection control should be integrated into general operations and it should be
considered at the beginning of the planning process related to new buildings and in those being
modified.
8
o MSF’s preferred order of environmental TBIC options preferred for a particular context
should be clear, including standard procedures to be followed when developing and
implementing these options.
o In resource-limited settings, TBIC measures that maximize natural ventilation should be
considered as one of the first options.
o
“Whirly-birds” are a good example of a low-cost intervention that can improve air
changes per hour (ACH).
o Cultural issues and community perceptions should be taken into account before deciding
on all TBIC measures.

MSF needs to lobby and educate Ministries of Health on the importance of prioritizing TBIC,
especially in countries with high TB and HIV burdens.
o An advocacy document, incorporating data on the impact of TBIC measures in reducing
TB transmission, should be prepared and used for lobbying (including within MSF).
o Further investment in TB prevention is justified not only by the reduction in patient
morbidity/mortality, but also by the reduction in cost of managing new cases of TB,
especially drug-resistant (DR) TB1.
o MSF focuses most of its TB efforts on early diagnosis and treatment of TB. Although
this helps to prevent new cases of TB, it is not enough; we need to invest further in
prevention of TB through IC measures.
o Although difficult, the cost-effectiveness of TBIC should be investigated and these
findings communicated to HQ and coordinators.

A proper handover of TBIC measures should be guaranteed, starting early in the handover phase
of all relevant projects.
III.C. Technical recommendations

The simplest environmental control solutions adapted for resource-limited settings should be
considered first, i.e. those measures that require little maintenance, are feasible and sustainable.
o Solutions that maximize natural ventilation are preferred.
o Simple mechanical ventilation, to assist natural ventilation as necessary, should be
considered next.
1
Each DR-TB case takes ~2 years to treat, which can cost >10,000 Euros when medications, testing, and other
interventions are considered.
9
o UVGI should only be considered in hot arid and cold regions, or other situations where
the preferred methods are not feasible2.

There is a need to develop common terminology (e.g. a glossary).

It is important to determine if environmental measures can be implemented in an existing
structure, if renovations are possible and/or realistic, or if a new structure must be considered.
An algorithm such as the one in Appendix 1 can be used for this analysis.

An analysis of the different environmental options available can be carried out using a simple
tool such as the one in Appendix 3.

There should be continuous follow-up of IC measures that have been introduced, including
measurement of outcomes from those already introduced, in order to be able to present ‘lessons
learned’.

After installation of any new equipment meant to improve TBIC, monitoring is necessary to
guarantee that the desired standard has been met (as stipulated in technical specifications) and –
if necessary – to make corrections and/or adaptations.

There should be continuous follow-up of IC measures that have been introduced, including
measurement of outcomes from those already introduced, in order to be able to present ‘lessons
learned’.

Regular screening of HCWs with TB skin tests (if not already known to be TST-positive) is an
additional way to measure effectiveness of TBIC measures implemented in some healthcare
facilities that MSF supports.

A community-based model of care for DR-TB patients (such as the one used in Khayelitsha,
South Africa) can reduce the risk of TB transmission at hospitals. There is a need to lobby for
similar community-based models of care.
III.D. Specific technical recommendations

When designing building layouts, there should be adequate space between buildings (at least 5
meters).

Waiting areas should have adequate ventilation (i.e. a minimum of 12 ACH).
o Waiting areas should be outside the main building wherever feasible, ideally in covered
open spaces
2
UVGI fittings are ideally used together with equipment that mixes air (e.g. ceiling and wall fans).
10
o If this is not possible, then waiting areas should take advantage of cross-ventilation
oriented to prevailing winds.

A template for consultation rooms should be developed with particular consideration for the
positioning of HCWs.

Current recommendations call for a minimum of 6 ACH in general consultation rooms and 12
ACH for TB consultation rooms3.

When designing new buildings in hot/tropical climates, central corridors should be avoided;
external passageways or accessible courtyards should be used instead.

Inpatient facilities should only be used to admit TB patients when it is absolutely necessary (i.e.
for clinical reasons).
o The sickest patients need to be located closest to the nursing station.
o Cohorting of patients is advised

separation of smear-positive from smear-negative, drug-sensitive TB patients

isolation of drug-resistant TB cases
o A well-ventilated communal area should exist, where patients can interact with their
families and/or other patients.
o It is important to make provision for and protect patients’ caregivers, who may have to
sometimes sleep in health facilities.

When it is necessary to admit DR-TB patients, they should be isolated in well-ventilated (i.e. >
12 ACH) individual rooms (~2.5 x 3 m in size) whenever possible, each with an en-suite toilet.

Toilets throughout healthcare facilities need to be adequately ventilated, aiming for a target of 20
ACH.

Sputum collection areas should be located outside wherever possible:
o Booths should be ventilated at both the top and bottom.
o 20 ACH should be the target.
o In cold climates, indoor sputum collection areas using UVGI can be an option.

The opening area on windows should be ~25% of the surface area of the floor of a room (if
feasible).

TBIC measures in laboratories should be robust, but done with consideration for the context4.
3
Note that future WHO guidelines are likely to include ventilation rates per person (e.g. litres/second/person) rather
than number of air changes per hour (ACH).
4
Bio-safety cabinets may not be a good investment if they are unlikely to be maintained after MSF hands over a
particular project.
11

There is a need to develop clear waste management procedures specifically related to TB.
III.E. Summary table of proposed specifications
Surface area
(m²)
Single
admission
rooms
Wards
Waiting
rooms
Sputum
collection
areas
Toilets
Consultation
rooms
Central
corridors
5
6
>7.5
(2.5 x 3)
Height
(m)
ACH
5
Opening
window
surface area
(m²)
Comment
>3
>126
>25%
Include en-suite toilets
>3.5
>6
>15%
Include hand-washing
basins
>3.5
>12
>15%
Preferably outside
>1.5
>2.2
>20
>50%
Preferably outside +
hand-washing basin
>1.2
>7.5
(2.5 x 3)
>2.5
>20
>6 (general)
>12 (TB)
>25%
>2
>3
>12
>25%
4.5 m² per
patient
3 m² per
patient
>3
>25%
Note that exceedingly high flow rates may be uncomfortable for patients!
Single rooms may not need flow rates as high as those in shared rooms.
12
Avoid putting them in
new buildings
IV.
BACKGROUND
Tuberculosis (TB) is an airborne disease and one of the major causes of morbidity and mortality
around the world, especially among people living with HIV (PLHIV). Despite being a curable
disease, the World Health Organization estimates that 1.7 million people died from TB in 2009, with
the highest number of those being in Africa.
The entire southern African region currently has a high burden of TB and HIV. Any person
spending time in a healthcare facility is at risk of inhaling the germ that causes tuberculosis (TB)
disease, including patients, their families, healthcare workers (HCWs) and other staff members.
Although measures to prevent transmission of TB are well documented, the issue of TB infection
control (TBIC) has not received nearly enough attention from Ministries of Health, the architects and
builders employed by them, and the wider medical community in such settings. Recent hospitalbased outbreaks of drug-resistant TB (DR-TB) have, however, raised awareness about the need for
improved TBIC measures that can break the chain of TB transmission.
The risk of TB transmission increases with time spent in healthcare facilities, leaving HCWs and
other staff particularly vulnerable to TB infection. Measures that prevent TB transmission need to
be a priority in each and every healthcare facility. Infection control committees (ICC) should ideally
exist in all healthcare facilities, and be responsible for implementation and supervision of the
different levels of TB infection control (TBIC) measures that prevent TB transmission
(administrative, environmental, and personal protection).
Although the three different groups of TBIC measures complement each other, administrative
measures are usually viewed as the priority, since reduction in the amount of TB droplet nuclei
suspended in the air can simplify the environmental and personal protective measures needed. The
unfortunate truth is that most healthcare facilities that MSF supports lack ICCs and dedicated staff to
ensure that the 3 groups of measures are being effectively implemented. Thus, building layouts and
designs that maximize dilution and removal of air are crucial in reducing the risk of TB
transmission in healthcare facilities.
Financial resources and available expertise, including national legislation and protocols, will all
influence the design of environmental TBIC controls.
There are a number of good reference
documents to help assess the state of TBIC and implement context-specific measures in individual
13
health facilities. But there is currently very little data to guide implementation of evidence-based
environmental and other measures that best prevent transmission of TB.
MSF does not have a great deal of expertise on TBIC as an organization but does have the potential
and resources to put into this issue, including operational research and development. Investing in
TBIC is ultimately cost-efficient, since it undoubtedly prevents new cases of drug-sensitive and
drug-resistant TB, the latter costing many thousands of Euros to treat each individual case! Simple,
effective and sustainable environmental TBIC control solutions are needed that are context-specific,
since healthcare facilities in different settings differ in design, the number and type of patients that
they serve, economic resources, healthcare service organization, climate and geography.
In light of the importance and challenges that many MSF projects face in developing and
implementing effective TBIC, a workshop was held over 3.5 days in Cape Town, South Africa in
February of 2011, focusing on environmental measures. MSF architects and builders met with
medical and other representatives, plus external specialists, to exchange ideas and solutions that
prevent transmission of TB and other airborne disease in healthcare facilities in resource-limited
settings.
14
V.
SUMMARY OF PRESENTATIONS AND DISCUSSIONS
TB is an airborne disease
TB is one notable example of an airborne disease, i.e. a disease caused by germs that are transmitted
through the air. People with active TB disease expel numerous tiny particles into the air when they
cough, sneeze, spit, etc. Particles between 1-5 microns in size, although invisible to the naked eye,
contain TB germs and can remain suspended in the air for many hours. TB transmission occurs
when other people inhale these ‘droplet nuclei’.
In most people with healthy immune systems, the TB germs remain ‘dormant’ in the lungs; however,
in the presence of a weakened immune system, the TB germs can grow uncontrollably inside the
bodies of children and adults, leading to symptoms of active TB disease (coughing, fever, weight
loss, etc). People living with HIV (PLHIV) are especially vulnerable to development of active TB
disease, and to make matters worse, TB is particularly difficult to diagnose in them, often requiring a
number of visits before the diagnosis of TB is made by the nurse or doctor. For these reasons, TB is
by far the main cause of morbidity and mortality in PLHIV.
In countries having a high burden of HIV and TB, primary healthcare (PHC) clinics by default
become HIV-TB clinics, since PLHIV frequently attend these facilities for diagnosis and treatment
of TB and other infections. Ministries of Health in southern Africa are in the process of integrating
TB and HIV services in many healthcare facilities.
When are people most likely to transmit TB?
When people with active TB cough, sneeze, spit, etc, they produce respiratory droplets that contain
TB germs which remain suspended in the air for a surprisingly long period of time.
An
understanding of the timing of TB transmission is important when developing TB infection control
strategies. People with active TB are most infectious when:

they have active TB in the lungs (i.e. pulmonary TB or PTB) and are coughing, sneezing, etc

there are many TB germs in the sputum (i.e. ‘smear-positive’ test results)

the TB has not yet been diagnosed

the TB has been diagnosed but treatment has not yet been initiated

they on incorrect TB treatment or not adhering properly

they are not improving on TB treatment (since they may have drug-resistant TB)
15
Key Point: People with active pulmonary TB (PTB) are infectious long before the
diagnosis of TB is made. It is those coughing, usually undiagnosed, people with active
PTB that represent the greatest threat of transmission.
When are people less likely to transmit TB?
It is also important to understand when people are less likely to transmit TB. There is little risk of
TB transmission:
 when people have EPTB (i.e. active TB outside the lungs)
 when those with pulmonary TB are no longer coughing, sneezing, etc.
 after those with drug-sensitive TB have been on correct treatment for several weeks
 correct treatment of those with drug-resistant TB also results in reduced infectiousness within a
short period (although somewhat less rapidly than DS-TB7)
Key point: TB patients are no longer infectious relatively soon after initiating
appropriate TB treatment. Thus, it is important to make the distinction between PTB
patients already on treatment (= much less infectious) vs. patients with undiagnosed
PTB (= much more infectious). IC measures need to be especially strong for all
coughing patients.
Who is most at risk of inhaling the TB germ?
The risk of inhaling TB increases with the duration of time spent with people having active
pulmonary TB (coughing, sneezing, etc). Household contacts, especially children and those sharing
the same sleeping quarters, are most at risk. There is potential for transmission of TB in the
community wherever coughing PTB patients spend time: churches, taxis, etc.
In a healthcare facility, those most at risk include:
o HIV-infected patients
o Family members that accompany patients
o Healthcare workers (HCWs)
o Other staff working in the facility (housekeeping, guards, etc)
Is prevention of transmission of drug-resistant TB any different from drug-sensitive TB?
7
Those with drug-resistant TB are no longer infectious once the person’s sputum culture result changes from positive
to negative…
16
Although drug-resistant TB, including MDR and XDR TB, is more difficult and expensive to treat
and has a higher risk of mortality, it is not any more infectious than drug-sensitive TB. The period
of infectiousness is likely to be somewhat longer for DR-TB patients, although precise data is
currently lacking.
Where are the ‘hot spots’ for TB prevention in a healthcare facility?
High-risk areas for TB transmission in a healthcare facility include those where coughing, usually
undiagnosed, patients with active PTB spend time. These areas include:
 Waiting areas
o Emergency departments
o HIV clinics
o Pharmacy
o X-ray departments
 Consultation rooms
 Sputum collection areas (and sputum booths8)
 Inpatient wards
 Toilets (since these are often enclosed areas)
 Laboratories (where processing of samples occurs for diagnosis of TB)
 Note that TB clinics tend to be a lower-risk area, since most of the patients being seen there are
improving (and no longer infectious) if on appropriate treatment!
Key point: In a health facility located in a high TB-HIV burden setting, there should
be UNIVERSAL implementation of TBIC measures, since patients with undiagnosed
active PTB can be found throughout the facility.
Organizing prevention and control of TB
TB infection control measures, designed to prevent others from inhaling the TB germs, are organized
into three groups as follows:

Administrative measures that decrease the production of infectious TB ‘droplet nuclei’
8
Note that some health facilities have sputum induction booths that are separate from sputum collection areas.
Sputum induction is necessary when patients have trouble producing a specimen for TB testing; a ‘mist machine’ or
other intervention helps such patients to cough up sputum, a process that results in the production of numerous TB
‘droplet nuclei’. Comprehensive information on sputum booths can be found in the Francis J. Curry National TB
Center’s ‘Tuberculosis Infection Control: A Practical Manual for Preventing TB’ (2007).
17

Environmental measures that reduce the concentration of TB droplet nuclei in the air

Personal respiratory protective measures that prevent inhalation of these droplet nuclei by
others
Administrative measures (the ‘software component’ of TBIC) should be the priority, since reduction
in the amount of TB droplet nuclei suspended in the air can ease implementation of environmental
and personal protective measures (the ‘hardware components’ of TBIC). The unfortunate truth is
that most healthcare facilities that MSF supports lack ICCs and dedicated staff to ensure that the 3
groups of measures are being effectively implemented. As previously mentioned, building layouts
and designs that maximize dilution and removal of air are crucial in reducing the risk of TB
transmission in healthcare facilities.
The role of Construction Logisticians
The role of construction logisticians in MSF has been to develop and implement construction
projects according to the needs of the project. With increasing awareness of the need for better
TBIC in settings having a high burden of TB-HIV, construction logisticians must be aware of the
different environmental TBIC options, as they will be asked to assess and improve environmental
TBIC measures in both existing and new healthcare facilities supported by MSF.

The vast majority of existing facilities have not been designed with TBIC in mind.
o TBIC assessments9 should be performed in all of them.
o Many will require modification to protect patients, their families and staff members from
airborne disease.

When new healthcare facilities are being contemplated, it is essential that construction
logisticians collaborate with medical team members in order to establish the TBIC needs and
ensure optimal prevention of TB through a combination of ‘hardware’ and ‘software’
components of TBIC.
The need for operational research related to TBIC represents another opportunity for collaboration
between construction logisticians and medical team members.
The role of the WHS Department
Support from the WHS department has over the years allowed projects to meet standard
requirements related to water, waste water, medical waste, dead bodies, vector control, etc. With
9
A good TBIC Assessment Tool can be found in the document ‘A Practical Guide to Implementation in Healthcare
Facilities and the Homes of Patients in Resource-poor Settings’ on MSF’s ‘Tuberculose Infection Control’ CD-Rom.
18
increasing attention to TBIC, the WHS department now has additional roles to help determine which
environmental measures are most appropriate for to prevent TB transmission in different projects:

Technical assessment of different environmental measures

Operational support to allow measurement of the effectiveness of the different TBIC options
(e.g. measurement of air changes per hour, or ACH)

Evaluation of equipment used to measure ACH

Evaluation of equipment used to provide UVGI

Provision of manuals containing technical briefs on issues such as climatic factors, human
resource requirements, measuring techniques, etc

Relay of practical information on the installation, operation, and maintenance of different
technologies

Training of construction logisticians and TBIC officers

Collaborate on further research and development related to TBIC
Environmental TBIC measures
Considerations when selecting a specific environmental measure
In addition to being effective at removing TB droplet nuclei from the air, environmental TBIC
measures being considered in resource-limited settings should be simple, sustainable, and require
little maintenance. A number of factors will need to be assessed:

Topography
o Is the project on a slope, hill or valley?
o What is the direction of the prevailing winds?
o Orientation of the sun, air pollution and green areas

Site planning
o Target population
o External layout of facilities
o Movement of people (patient flow)
o How many people are likely to be using the facility

Building design
o Form, shape, and volume
o Openings (size, location, wind deflectors)
o Shade (screens, trees)
19
o Roof (shape, ventilated)
o Building material

Is it appropriate for an existing or new building?

National legislation and policy

Local culture and community perceptions
Only thorough consideration of the above factors will allow environmental controls that are best
suited to a particular facility and project situation. If modifications are being made to existing
facilities, then these should be simple but durable. If a new facility is being planned, then the
building design should maximize natural ventilation.
Environmental control options for field projects (see also Appendix 3)
Environmental controls in TBIC are aimed at reducing the concentration of TB droplet nuclei
through dilution, extraction or purification of the air. This can be achieved in MSF field projects
through natural ventilation, mechanical ventilation and/or ultraviolet germicidal irradation (UVGI).
Since coughing, usually undiagnosed, patients with active TB are found in a variety of different
settings (HIV clinics, prisons, homeless shelters, etc), the option(s) chosen will vary widely in
different projects.
1. Natural ventilation
Natural ventilation has been used since the 16th century in attempts to control airborne disease. It is
simple, inexpensive and an effective method to reduce the concentration of TB droplet nuclei in
resource-limited settings where MSF tends to work.
Determinants of natural ventilation

Exposure to prevailing wind

Wind speed

Cross-ventilation

Location of building

Location of room

Stack effect10
The following explanation of ‘stack effect’ (also called stack pressure) is taken from WHO’s 2009 publication
‘Natural ventilation for Infection Control in Healthcare Settings’: Stack pressure is generated from the air temperature
or humidity difference between indoor and outdoor air. This difference generates an imbalance in the pressure gradients
10
20

Design of windows

Size of windows

Ground elevation
Advantages of natural ventilation

High air changes per hour (ACH) can be achieved

Cost-free (after initial costs)

Maintenance-free

Feasible in a number of different relevant areas within health facilities:
waiting rooms,
emergency departments, etc
Disadvantages of natural ventilation

Climate-dependent

No control over direction of contaminated air

Increased possibility of noise pollution

Can compromise security

Fire safety
Wind-driven roof turbines (“whirly-birds”)
Wind-driven roof turbines have predominantly been used to improve ventilation in industrial
buildings and homes, usually in ceiling spaces, and are now being used to assist natural ventilation in
healthcare facilities. They work by creating a pressure differential between the inside of a room and
the outside environment which results in extraction of contaminated air from the room. The air inlet,
in the form of wall or door grate, allows clean air to come in from outside to replace the extracted
air. Given that the whirly-bird is positioned in the ceiling and the air inlet is close to floor level,
whirly-birds allow for greater mixing of air throughout the room, and minimise the opportunity for
‘dead’ air spaces where contaminated air may remain.
of the interior and exterior air columns, causing a vertical pressure difference. When the room air is warmer than the
outside air, the room air is less dense and rises. Air enters the building through lower openings and escapes from upper
openings.
21
Operational research into the effectiveness of whirly-birds is currently ongoing in Cape Town, in
which the number of air changes per hour (ACH) in clinic rooms is being measured to allow
comparison of wind-driven turbines and open windows, under varying wind speed conditions.
Preliminary results include:

The use of whirly-birds can achieve an acceptable number of ACH, even at low wind speeds

There is less variation with varying wind speeds compared to open windows

Whirly-birds are less likely to be closed by staff and patients

There are fewer draughts with whirly-birds at similar ACH levels
Further investigation is needed in order to determine which design of turbines works best, how big
the air-intake grates should be relative to turbine size, how many turbines are needed for different
room sizes, and how ACH produced by turbines compare to those from cross-flow ventilation.
2. Mechanical ventilation
Mechanical ventilation systems create differential pressure between two areas by extraction and
supply of air through the use of simple extractors, centralized ventilation and air conditioners. These
systems are complex in most cases, requiring highly skilled personnel for their design/calculation,
installation, monitoring and maintenance. They also require a constant supply of electricity. For
these reasons, plus their (ongoing) high expense, the use of mechanical ventilation tends to be
restricted to high-risk areas and where natural ventilation is not possible. For example, in a facility
1000 m² in size, it may cost as much as:

~100,000 Euros to install a complex mechanical ventilation system

running costs of ~25,000 Euros annually, if the system operates 24 hours per day

5000 Euros in maintenance costs annually
A survey of some hospitals in Thailand where mechanical ventilation systems were in operation
showed that indoor ventilation was satisfactory in only 44% of areas, while 74% of emergency
departments and radiology areas had inadequate ventilation. Conversely, the majority of naturally
ventilated rooms in the same facilities were adequately ventilated.
Amongst all the mechanical ventilation design options, simple extractors are recommended for use
when natural ventilation needs to be assisted in resource-limited settings having a high burden of
HIV and TB, since they are less expensive and easy to install and maintain.
3. Ultra Violet Germicidal Irradiation
22
Ultraviolet germicidal irradiation (UVGI) involves the use of UV light to purify air to the equivalent
of at least 6 ACH. In order for UVGI to be effective, the TB germ must be exposed to a sufficient
dose of ultraviolet-C (UV-C) radiation at a wavelength of 253.7 nanometers. Since sunlight only
carries UV-A and UV-B light, both of which are ineffective against the TB germ, it is necessary to
create artificial UV-C. However, direct exposure to UV-C can cause inflammation of the eyes
(“keratitis”) and redness of the skin (“erythema”).
Advantages of UVGI lamps and fittings

Potential solution for hot arid and cold zones

Low energy consumption (lamp input 30W per 18 m² of ground surface)

Relatively easy maintenance (but essential for effectiveness)

Can be easily added to existing buildings
Disadvantages of UVGI lamps and fittings

Need to be correctly designed

Decreased effectiveness of 30-45 % if relative humidity of 75-100%

High risk of potential exposure of HCWs to the UV light (which should only be fitted in the
upper parts of rooms and/or with louvered fittings)

Need to be replaced approximately every 8000 hours (= ~ once per year)

Purchase is expensive

Require controlled mixing of air

Contain mercury which requires eventual disposal of hazardous waste
UVGI is not recommended as the first choice in all situations and does not replace ventilation
systems. Knowledgeable staff having the proper equipment should perform assessment, design,
installation and verification.
Building designs to ensure adequate TBIC in hospital settings
Infection prevention and control (IPC) is a process made up of multiple procedures and practices,
evidence-based whenever possible, that are used to ensure a safe environment for patients and staff.
This section focuses more on hospital settings, although the principles are the same for primary
healthcare clinics. See Appendix 2 for possible PHC clinic floor plans.
23
Basic principles of IPC

Reduce exposure to the number of infectious particles

Reduce the number of people exposed to an infectious source

Be aware of routes of transmission of common infectious diseases
Issues to consider when designing hospitals

All services should ideally run along outside walls

Building designs should accommodate for adequate space, natural light, and ventilation

Sewerage pipes should not cross above high care areas

Drinking water and sewerage pipes must be laid separately

Carpets should not be placed in clinical areas

Covered continuous flooring rising to 25 cm (there should be no cracks)

Easily washable floors, walls and ceilings (no tiles)

No false panels on ceilings as they are difficult to clean

Where mechanical air supply and extraction is used, exhausts should preferably be placed
opposite air inlets

When dealing with multiple storey buildings, consider placing potentially infectious patients on
the highest floor, where the roof can be converted to an outside area for patients.
Issues to consider when designing inpatient wards

Smaller bed cohorts are easier to manage and reduce the risk of TB transmission

Single rooms have a number of advantages

Ratio of isolation beds to total number of hospital beds should be based on the infectious disease
profile of a particular setting

En-suite ablution facilities should be available for all DR-TB beds/patients

Dedicated areas should be available for specialised care, particularly related to TB

In a multi-bedded ward, infectious patients (I.e. coughing, sneezing, etc) should be separated
from non-infectious patients by increasing space between the two groups

Provisions should be made for accommodate caregivers
Ward layout and design
24

Space between beds should be minimum 2.5 m (increasing to 3.6 m in high-care units)

Wards should be kept clean and dry

There should be adequate space in the wards to allow easy access

Oxygen, suction and electrics should be placed along the walls

Bed-side lockers should be provided

External spaces in some facilities can be turned into wards
Ventilation

Areas of inadequate air mixing (i.e. ‘dead’ air spaces) should be avoided

Windows should be able to be opened

Direction of air flow should be from patient areas to the outside atmosphere, not towards the
corridors

Natural ventilation should be taken advantage of, wherever possible

Self-closing doors with baffle plates can be used to maintain air flow

If mechanical ventilation is used, it should be quiet and unobtrusive
Staff facilities
The following staff facilities should be provided wherever possible to avoid inappropriate use of
other areas within the healthcare facility by HCWs:

Changing areas

Rest rooms

Tea rooms

Toilets and storage facilities

Conference areas

Offices

Administration area
Laboratory design and layout
Processing of sputum and other specimens presents a significant risk of transmission of TB and other
infectious disease to laboratory personnel. All staff working in laboratories should be properly
trained and have access to proper equipment in order to minimize the risk of TB transmission. The
layout of a laboratory should allow the different steps involved in processing of specimens to take
25
place in proper areas, thereby ensuring a safe work area environment. In addition, movement of
people within a laboratory should be minimized.
Bio-safety cabinets
There are two classes of biosafety cabinets (BSC).
i. BSC – Class I

draws air into the cabinet and exhausts it to the outside

protects the work environment from infectious aerosols

produces negative pressure in the room
ii. BSC – Class II

laminar flow and exhausts air

protects both the specimen and the HCW

poor practices and inadequate maintenance increase the risk of transmission of disease
Airflow should be monitored and recorded daily for both types of cabinets. A Class I BSC is ideally
placed in most laboratories, but because they are expensive and require constant monitoring, this is
not always possible. Instead, simpler solutions tend to be used in laboratories located in settings
where MSF operates, including the use of an exhaust fan and a hood.
Safe disposal of bio-medical waste
All materials used to process specimens containing TB are considered infectious waste, which
presents a risk to HCWs and the community.

Such waste must either be sterilized (by autoclaving) or be subjected to high-level disinfection
before it leaves the laboratory.

Contaminated materials, including sputum containers, should be discarded in peracetic acid or
5% phenol (laboratory jars).

All surfaces should be cleaned with hypochlorite after work has been finished at the bench.
Safe TB laboratory practices

Risk assessments should be routinely performed

Ventilation and airflow patterns should be controlled

Overalls and well-fitting gloves should be worn (face cover not necessary)

Frequent and appropriate hand-washing
26

Use of disinfectants and proper waste disposal

No eating, drinking, smoking or use of mobile phones inside the laboratory

Avoid leakage from specimen containers +/- contamination of work forms

Control aerosolization from specimens and prevent spills

Have an emergency plan and supplies available
Architecture and infection control
Architectural input into a building design is made up of a number of stages that starts when a client
approaches the architect with a brief, budget and/or site together with a timeframe. The architect
then presents a proposed contract, i.e. a description of the work and fees as recommended by the
national architectural institute and the regulatory body.
In the five stages briefly outlined here, note that respiratory infection control measures should be
considered from the outset (i.e. Stage 1)!
Stage 1: Appraisal and definition of the project
The architect receives, appraises and reports on the client's requirements with particular regard to
site information, planning and statutory regulations, and budget.
Stage 2: Design concept
The architect prepares a design concept in broad outline showing space provisions, planning
relationships and materials and services intended to be used.
Stage 3: Design development
The architect develops the design concept in sufficient detail to:

Define the construction of the building

Spatially coordinate the work designed by consultants and specialists

Review the design with relevant authorities
Stage 4: Technical documentation
The architect prepares construction documentation and coordinates it with the work designed by
consultants and specialists.
Stage 5: Contract administration and inspection
Challenges in implementation of environmental TBIC measures in the field

The TBIC knowledge capacity amongst construction logisticians and MSF HQs needs to be
strengthened in order to better support the medical needs of projects in resource-limited settings
having a high burden of TB and HIV.
27

It is unclear in the field about the position of MSF HQs with regard to implementation of TBIC
in particular settings. A number of questions need to be answered including:
o How much responsibility is MSF willing to take for TBIC vs. the MoH?
o How much capacity does the MoH have to take it up?
o How much capacity does MSF have to take it up?
o Is TBIC a medical priority for MSF?

There are no guidelines for construction logisticians on how to select and develop appropriate
environmental measures.

There is not a clear understanding of TB transmission in high-risk areas of health facilities; such
areas sometimes remain unidentified and are left out of a TBIC implementation plan.

Insufficient collaboration between medical and logistics teams within projects can result in the
‘hardware’ not being complemented by the ‘software’, which ultimately affects the effectiveness
of environmental TBIC measures.

Government legal and regulatory requirements are not always clear or easy to follow.

There is a risk that TB patients could be stigmatized.
Possible solutions to challenges

MSF HQs need to invest further in a number of different issues related to TBIC:
o Trainings
o Engaging with TBIC specialists
o Operational research and development

Since we have a responsibility to ensure that patients attending and HCWs (and other staff)
providing services do not become infected with TB, it is important that our organization invests
in adequate TBIC in order to prevent TB transmission within healthcare facilities.

Development of internal guidelines for logisticians and builders (in collaboration with the
relevant medical personnel) that clarify the environmental controls preferred by MSF, and
standard procedures to be followed when implementing them.

Universal implementation of environmental TBIC measures should be promoted in healthcare
facilities located in settings having a high burden of TB and HIV. There is evidence showing
that undiagnosed TB patients contaminate air in areas of such facilities other than TB clinics:
general waiting areas, etc. There is also evidence to show that medical students, HCWs and
28
patients who spend time in healthcare facilities are at increased risk of becoming infected with
TB.

Encourage increased collaboration between medical and logistics teams in the selection, design
and implementation of environmental control measures.

Cultural issues and community perceptions should be considered when selecting environmental
controls, which implies the need to ensure (set up and) involvement of local TBIC committees.
It is also important that the medical team gives feedback to logistics on how equipment or
structures are being used by patients.
29
VI.

AREAS THAT REQUIRE FURTHER OPERATIONAL RESEARCH
Identification and standardization of equipment and protocols for measuring the effectiveness of
TBIC control measures (e.g. the best tool to measure natural ventilation in resource-limited
settings)

Optimal design of sputum booths in resource-limited settings

Effectiveness of solar extractors and use of alternative energy (i.e. green technology)

Tools for identification of high risk zones in healthcare facilities

Effectiveness of automatic equipment (e.g. automatic doors)

Identifying the optimal use of space in healthcare facilities

Optimal use of wind-driven roof turbines (“whirly-birds”) in assisting natural ventilation

Optimal size of open windows relative to the room

Best type of windows for use in healthcare facilities

Pilot projects in different climatic zones and documentation of these efforts to determine which
technologies work best in which settings

Research into the efficient and safe use of UVGI technology especially in hot arid and cold
climates

Use of ventilation hoods as a simple and cheaper alternative to more expensive laboratory
recommendations (e.g. bio-safety cabinets)
30
VII.
CONCLUSION
Since it is those patients with undiagnosed active pulmonary TB that represent the greatest risk of
transmission, TB infection control measures to protect health care workers and other patients should
be implemented throughout healthcare facilities in high TB-HIV burden settings.
As most resource-limited settings in high TB-HIV burden settings lack dedicated staff to ensure
effective implementation of administrative and personal protective infection control measures,
building layouts and designs that maximize dilution and removal of air are crucial in reducing
the risk of TB transmission.
Building layouts and designs that maximize natural ventilation represent the best and most
sustainable solutions.
31
APPENDIX 1
32
APPENDIX 2
33
APPENDIX 3
APPENDIX 4: LIST OF PARTICIPANTS
Name of
Participant
E-mail address
Office/mission
Position
Domain
Coming
From
Rod Escombe
Joos Van Den
Noortgate
[email protected]
Imperial College
London
Medical/Ventilation
Medical
London
[email protected]
OCB-HQ
WHS Referent
WHS/construction
Brussels
Marcello Fodde
Jean Eric
Schaeffer
Yannick
Garbusinski
[email protected]
OCG-HQ
OCB-HQ
Construction
Support Tech
Coordination
Geneva
[email protected]
Construction referent
Log OPS&Technical
Coordinator
[email protected]
OCB HQ
Construction referent
construction
Brussels
Kunio Yamazumi
[email protected]
TBA
Construction Log
Architecture/Construction
Tokyo
Michael Browne
[email protected]
OCG-Swaziland
Architect/constructor
construction
Swaziland
Vera Habedi
[email protected]
OCG-Swaziland
Infection Control Officer
TB Infection Control
Swaziland
Ronan Guédé
McPharlen
Machinjiri
[email protected]
OCB-HQ
Cell 6 Log Polyvalent
Logistics
Brussels
[email protected]
Thyolo project Logistician
Logistics
Malawi
Roberto Pizzorni
[email protected]
Mozambique
[email protected]
CoTL Mozambique Mission
Mavalane project construction
Log
Logistics
Bruno Cardoso
Alec Ross
Andreassen
Logistics
Mozambique
[email protected]
MSF-OCB
MSF-OCB
Mozambique
MSF-OCB
Mozambique
MSF-OCB
Mozambique
Thyolo project construction Log
Architecture/Construction
Malawi
Northan Hurtado
[email protected]
MSF-OCP
TB Adviser, TBWG IC Referent
Medical
Paris
Frank Rammeloo
[email protected]
OCA-HQ
Construction Referent
construction
Amsterdam
Oliver Munnier
[email protected]
OCP-HQ
Bio Medical Referent
Medical
Paris
Jerome Leglise
[email protected]
WHS Referent
WHS/construction
Paris
Shahid Mohamed
[email protected]
Regional HIV/TB Log
Infection Control
Pakistan
Samuel Mkoko
Marcello
Mazzotta
[email protected]
Manzini Project ICC
Infection Control
Swaziland
Swaziland
[email protected]
Manzini Project tech log
In charge of the container
hospital in Haiti
Tech Log
Francis Bernaert
Heman
Nagarathnam
OCP-HQ
Regional TB/HIV
Log
MSF-OCA
Swaziland
MSF-OCA
Swaziland
Architect/supervisor
Haiti
Logistics
Coordinator
construction
Brussels
Logistics Coordinator
Logistics
Ethiopia
[email protected]
[email protected]
35
Brussels
Mathew Grimaldi
[email protected]
In between mission
Architect/constructor
Working on Construction
Guideline of OCs
construction
Spain
Gilheme Coelho
[email protected]
Kees Keus
Luiz Otavio
Guimaraes
[email protected]
OC HQ Architect
MSF-OCA
Swaziland
Architecture/Construction
Brazil
Head of Mission
Medical
Swaziland
Mozambique
CoTL
Mozambique
Architect/constructor
construction
Armenia
[email protected]
MSF-OCG
MSF-OCP Armenia
Mission
MSF-OCB South
Africa
Chloe Decazes
[email protected]
Pascal Tourneux
Next CoTL
CoTL
Brussels
Helen Cox
Gilles Van
Cutsem
[email protected]
OCB-South Africa
Epidemiologist/Ventilation
Epidemiology
CT
[email protected]
OCB-South Africa
Medical Coordinator
Medical, Epid
CT
Chipo Takawira
[email protected]
OCB-South Africa
ICC Khayelitsha Project
CT
CT
Terufat Deneke
[email protected]
MSF-OCB-ZA1
Logistics Coordinator
Logistics/Construction
CT
Eric Goemaere
[email protected]
SAMU
Regional Advisor HIV/TB
Medical, Epid
CT
Peter Saranchuk
[email protected]
SAMU
TB-HIV Adviser
Medical, TB
CT
Helen Bygrave
[email protected]
SAMU
HIV-TB Support Officer
Medical, HIV
CT
Alicia Bosman
Virginia De
Azevedo
[email protected]
City of Cape Town
Director City Health facilities
Health structures
CT
[email protected]
DOH Khayelitsha
Khayelitsha SD Manager
Medical,DoH
CT
Shaheen Mehtar
[email protected]
Tygerberg Hospital
Medical
Stellenbosch
Ashley Hemraj
Cornel
Badenhorst
[email protected]
Architecture/Construction
CT
Mechanical Engineer
Ventilation
CT
Simone Le Fevre
[email protected]
City of Cape Town
CM3 Consulting
Engineers
Simon and Cook
Arch
Head of Academic Unit for IPC
Development Services, Sr.
Architect
Architect, Prof UCT
Architecture
CT
Shannon Maree
[email protected]
City of Cape Town
Senior Mechanical Engineer
Ventilation
CT
[email protected]
[email protected]
36