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WH0/V&B/D0.14
ENGLISH ONLY
DISTR.: GENERAL
’7 JUL 2000
Making use of
Vaccine Vial
Monitors
Flexible vaccine management for polio
supplementary immunization activities
DEPARTMENT DF VACCINES
AND BIOLOGICALS
World Health Organization
Geneva
lj
WHO/V&B/00.14
ENGLISH ONLY
DISTR.: GENERAL
1
Making use of Vaccine Vial
Monitors
Flexible vaccine management for polio
supplementary immunization activities
1
1
DEPARTMENT OF VACCINES
AND BIOLOGICALS
WW?
World Health Organization
Geneva
2000
The Department of Vaccines and Biologicals
thanks the donors whose unspecified financial support
has made the production of this document possible.
This document was produced by the
Expanded programme on Immunization Team
of the Department of Vaccines and Biologicals
Ordering code: WHO/V&B/00.14
Printed: April2000
This document is available on the Internet at:
www.who.int/vaccines-documents/
Copies may be requested from:
World Health Organization
Department of Vaccines and Biologicals
CH-1211 Geneva 27, Switzerland
• Fax: +22 791 4193/4192 • E-mail: vaccines@who.int •
© World Health Organization 2000
This document is not a formal publication of the World Health Organization (WHO), and all rights are
reserved by the Organization. The document may, howevei; be freely reviewed, abstracted, reproduced
and translated, in part or in whole, but not for sale nor for use in conjunction with commercial purposes.
The views expressed in documents by named authors are solely the responsibility of those authors.
Gh-
07063
Contents
1. Introduction........................................................................................................... 1
2. The ‘traditional’ cold chain for campaigns....................................................... 2
3. The vaccine vial monitor..................................................................................... 3
3.1
Important WM reminders........................................................................... 5
4. The fast chain......................................................................................................... 6
4.1 What is it?....................................................................................................... 6
4.2 What is the advantage?.................................................................................. 6
5. When is a flexible cold chain required?.............................................................. 7
6. Planning issues for a flexible cold chain............................................................. 9
7. Hints....................................................................................................................... 11
7.1 Teaching and believing WM...................................................................... 11
7.2 Melting icepacks........................................................................................... 12
7.3 Vials at the end of the campaign or session................................................ 13
7.4 What to do in case of shortages/surpluses................................................. 13
Annex 1: WM Fact sheet....................................................................................... 15
iii
1. Introduction
All countries where polio transmission is not yet interrupted have one or several of
the following characteristics in common:
•
a large proportion of difficult-to-reach populations, either due to geographic
inaccessibility, or the persistence of pockets with limited access to health services
(high population density, nomads, deprived groups, etc.);
•
destroyed or unreliable transport infrastructure;
•
insufficient and/or inoperable cold chain equipment;
•
lack of sufficiently trained technical staff;
•
insecurity due to ongoing conflict, mines, etc.
The heat sensitivity of oral polio vaccine (OPV) and the ensuing necessity to keep
the vaccine cool is one of the major complicating factors for the implementation of
polio campaigns under these conditions.
However, because of the short duration of campaigns for polio eradication and the
presence of the vaccine vial monitor (WM, see chapter 3) on the OPV vials, it is
now possible to implement a more flexible cold-chain strategy than could previously
be envisaged.
Although this strategy is especially appropriate for countries in conflict, post-conflict,
or with insufficient infrastructure, it should not be limited to them. Any national
immunization day (NID), even one conducted among easily-accessible populations,
can be more effective if it adopts a more flexible approach.
These guidelines are designed specifically for OPV use during national immunization
days/subnational immunization days (NIDs/SNIDs) and mop-ups only. A full-scale
cold chain is necessary if measles vaccine is added to NIDs, since this vaccine does
not have a WM and degrades rapidly in ambient temperatures after reconstitution.
WHO/V&B/00.14
1
2. The ‘traditional’ cold chain
for campaigns
The traditional cold chain employed during campaigns uses predominantly
refrigerators and freezers for the storage of vaccines and cold boxes and vaccine
carriers for their transport. The presence of ice is ensured at all times during transport
and at the vaccination site and is a prerequisite for the continuation of the work of
the teams.
The heat sensitivity of the vaccines and the impossibility to monitor heat exposure
justified this cold chain model.
However, this model does have a number of disadvantages:
•
It makes it difficult to reach populations with limited access, because of:
the cold life of the equipment in relation to the distance to be travelled;
the (seasonal) lack of accessibility of these populations due to the nature
of the terrain;
- the weight and volume of equipment, which increase with travelling time
and distance;
— the amount of equipment required to cover remote and/or dense
populations;
— lack of flexibility due to the inherent necessity of requiring ice all the time
at every stage.
A cold chain designed specifically for NIDs is relatively costly:
—
—
•
a cold chain designed for NIDs may be badly adapted to routine services,
because the latter are less demanding in terms of freezing capacity and
may require different types of equipment all together (less compression
appliances, generators, etc.);
- equipment will run around the clock to satisfy the need for icepacks to
keep vaccines cool.
Traditional cold chain management has a top-down approach leaving little room
for creative problem solving by health staff: in the traditional cold chain no ice
means no immunization.
—
•
2
Making use of Vaccine Vial Monitors
3. The vaccine vial monitor
Oral polio vaccine is the most heat sensitive of all vaccines used in the
Expanded Programme on Immunization (EPI). Storage and transport have to comply
with good cold chain practices. However, cumulative heat exposure can now be
monitored with the help of the vaccine vial monitor (WM),1 which can be found on
all OPV supplied by UNICEF since 1997.
A heat sensitive square within a circle (figure 1) changes colour under the combined
influence of heat and time. If after exposure to heat for a certain amount of time,
the square reaches the same colour, or becomes darker than the circle, the vial should
be discarded.
Figure 1: the WM
Inner square is lighter than outer ring.
USE the vaccine, if expiry date not reached.
As time passes: Inner square is still lighter than
outer ring.
USE the vaccine, if expiry date not reached.
Discard point: Inner square matches the colour
of outer ring.
DO NOT use the vaccine.
Beyond the discard point: Inner square is
darker than outer ring.
DO NOT use the vaccine.
Vaccine vial monitor - Training guidelines. WHO/EPI/LHIS/96.04 (update planned for 2000).
Vaccine vial monitor and open vial policy. WHO/EPI/LHIS/96.01 (update on multi-dose vial
policy in process).
WHO/V&B/00.14
3
OPV, supplied by WHO accredited manufacturers, retains satisfactory potency for
at least 48 hours at an ambient temperature of 37°C. The WM reaches the point
where OPV should be discarded before that.
At lower temperatures the loss of potency is considerably slowed down and the time
it takes the WM to reach the discard point increases subsequently.
Table 1 gives the WHO/UNICEF specification of WMs for OPV. It shows that,
for example, at 25°C continuous ambient temperature the WM will reach the
discard point only after 7 days.
Table 1: WM reaction rate for OPV2
Continuous ambient
temperature
Number of days before
WM on OPV will reach
discard point
+ 37°C
1.5-2 days
+ 25°C
7 days
+ 4°C
180 days (6 months)
- 20°C
2 years
The WM allows the user to see at any time if OPV can still be used in spite of
possible cold chain interruptions. If necessary, health staff and management can
then take the required corrective measures.
Besides this important corrective management based on WM monitoring, it is feasible
and justifiable to use the WM to plan a more flexible, less stringent and cheaper
cold chain, which is of particular importance for NIDs.
OPV can be safely used beyond the cold chain until the WM reaches the discard
point The length of time will depend on ambient temperatures and the quality of
the cold chain till that point.
With the WM, the absence of ice is not a reason to interrupt
immunization
2
Equipment performance specifications and test procedures. E6: Temperature monitoring devices.
WHO/EPI/LHIS/97.09.
Making use of Vaccine Vial Monitors
The advantages of the use of WMs during NIDs are:
•
teams can go further in time as well as geographically, due to less bulky
equipment and decreased dependence on re-supply of ice;
•
difficult access and weak cold chain cease to be reasons not to immunize
population groups usually missed during NIDs and routine services;
•
because fewer icepacks are required, freezing can be faster and with less
equipment;
•
cold chain costs can decrease due to these factors;
♦
health worker and stock manager can decide which vials to use first or in
nearby areas with good cold chain on the basis of WM status;
•
reduction of wastage. With the help of the WM several countries have
abandoned the policy of discarding OPV vials at the end of a session or in case
of cold chain failure. This has led to important reduction in wastage from a
previous 25% to 10% or lower. Experience in many countries now shows that
few WMs reach the discard point during the campaigns.
Proactive management should lead to a tailor made cold chain, combining WM
and equipment specifications on the one hand with excellent micro planning and
sensitized health workers on the other. This as opposed to the traditional top-bottom
and “ice everywhere” approach.
Annex 1 presents the main facts regarding the WM and is meant to be used as an
information sheet or as training materials.
3.1
Important WM reminders
•
The WM gives only information about the vial to which it is attached.
It can not be used as indicator of heat exposure to other vaccines,
because the cold chain history of the latter may be very different.
•
The expiry date of a vial has priority over the WM. If the expiry date is
reached, the vial should be discarded even if the WM suggests the vial can
still be used.
The better the overall cold chain, the more teams can benefit from
the WM during the NIDs
WHO/V&B/00.14
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4. The fast chain
4.1
What is it?
The fast chain is a cold chain strategy that seeks to increase the effectiveness of
campaigns by a reduction of the dependence on cold chain equipment through
pro-active management and short supply lines.
The number of refrigerators and freezers required for intermediate storage is kept
to a strict minimum through the intense use of cold boxes as secondary distribution
points after vaccines leave the central/regional stores.
Although the fast chain was already applied before vaccine vials had VVMs,
the combination of both increases even further the possibilities for a flexible cold
chain during NIDs.
4.2
What is the advantage?
The elements described above reduce dependence on refrigerating and freezing
systems at peripheral level.
The fast chain, in combination with the WM, has the following advantages:
•
difficult to access populations can be reached without installing additional
equipment at peripheral level;
•
installation of a specific NIDs cold chain with its excessive need of ice
and probable incompatibility with the routine programme requirements,
can be prevented;
•
the cold chain can be cheaper, although this may be offset by the increased
need for freezing equipment at central level.
6
Making use of Vaccine Vial Monitors
5. When is a flexible
cold chain required?
Clearly, by reducing the dependence on cold chain equipment and increasing the
flexibility of the teams, the fast chain and the use of WMs are ideal for any country
or region where the infrastructure makes it difficult to implement the traditional
cold chain.
However, there is no reason to limit either of them to these difficult conditions.
On the contrary, they should really be seen as the first step of the cold chain of the
future, which will have the following characteristics:
•
strengthening of central and regional stores;
•
WMs on all vaccines;
•
increased flexibility at peripheral levels.
The fast cold chain and the WM can be used in any country implementing
NIDs with OPV only.3
Even for a country with a well-established cold chain, there is no need to stretch
icepack freezing and storage capacity to the maximum, or provide teams with
materials, which are too heavy, thus limiting their flexibility. Figure 2 gives an example
of a traditional and flexible cold chain.
With the fast chain and the WM, population groups that are
usually missed during NIDs, can be immunized.
Since vitamin A does not require to be kept cool, its addition to polio NIDs is irrelevant for the
cold chain strategy.
WHO/V&B/00.14
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8
Making use of Vaccine Vial Monitors
6. Planning issues for a
flexible cold chain
When planning for a flexible NIDs cold chain the following key elements have to be
considered:
1)
It is the task of management at central and regional level to determine the
length of time OPV can be safely taken beyond the cold chain. This must be
based on:
•
•
•
•
•
The duration of the campaign.
Inversely, the duration may be adapted to achieve an optimal cold chain
strategy.
The quality of the cold chain till that point. If central and regional storage
and transport conditions are sub-standard, the WM will start changing
colour before the actual campaign.
Ambient temperatures. The highest temperature for the country should
normally be taken. To prevent possible confusion, a lower temperature
should only be taken if it refers to a region where planning and
implementation are clearly separate from the other regions.
The WM specification (see tables 1 and 2), respecting a good safety
margin.
Cold life4 of the type of vaccine carriers and cold boxes used in the
country/region. The cold life of the equipment decreases with the decrease
of the number of icepacks.
— Options 1: the cold life of the cold box should cover supply,
duration of campaign and the return of left over vaccines to the store.
- Option 2: the cold life only needs to cover supply, because either
vaccine is not brought back or icepacks can be re-supplied.
OPV can be safely used beyond the cold chain until the WM
reaches the discard point.
The cold life of cold boxes and vaccine carriers is the time it takes between the moment frozen
icepacks are put in the box/carrier until the moment any of the vaccines reaches +10°C. The cold life
of all boxes/carriers is given in the Product Information Sheets (see the English edition WHO/EPI/
LHIS/97.01 and the Supplement WHO/EPI/LHIS/98.03).
WHO/V&B/00.14
9
2)
Once the general context is defined, the equipment and number of icepacks
for the teams must be determined at district level through rigorous micro
planning.
3)
Vaccines should be kept in central/regional stores as long as possible before
the NIDs/SNIDs/Mop-up.
Table 2: Example how to adapt the amount of equipment
to the ambient temperatures
Length of time away from
the centre, without re-supply
of icepacks
Equipment
(ambient temperatures
25-35°C)
Equipment
(ambient temperatures
> 35°C)
< 24 hours
each team 1 carrier without
icepacks*
each team 1 carrier with 1-2
icepacks
24 - 72 hours
each team 1 carrier with all its
icepacks
each team 2 carriers: 1 with
vaccine and 1 with extra
icepacks
4-6 days
1 carrier per team and
1cold box for each 4 teams
1 carrier per team and
1 cold box for each 4 teams
Managers may decide to give 1 icepack for the ease of mind of the teams.
4)
Because of the limited cold life of the cold boxes, transport to regions where
the fast chain is applied, needs to take place at the latest possible time before
the beginning of the campaign and requires therefore very rigorous planning.
5)
Cold boxes can be used to transport icepacks and vaccines for a number of
teams to a secondary distribution point (see figure 2).
6)
Freezing the correct quantity of icepacks may have to start up to 8 days before
the campaign. If generators are used, they will have to run for 24 hours a day
to achieve satisfactory freezing.
10
Making use of Vaccine Vial Monitors
7. Hints
7.1
Teaching and believing VVM
•
To gain confidence in. WM, EPI managers should not hesitate to test for
themselves the extent to which OPV can safely be taken out of the cold chain
(see figure 3).
The proof of the pudding is the eating: test WMs yourself !!
When health workers are trained in the use of the VVM it is
strongly recommended to bring WM samples to show during the workshop
that OPV can be taken out of the cold chain for a certain length of time.
Only a practical demonstration is convincing.
The teams must be clearly instructed to keep vaccines cool at all time,
monitor the VVM and continue immunizing until the WM has reached
the discard point, or until the end of the campaign.
Teams must understand they can use their own imagination to solve problems
and overcome obstacles in reaching all children in their catchment area.
This is quite different from the traditional cold chain approach and convincing
trainers are crucial to get the message across.
WHO/V&B/00.14
C- H * 1i
07069
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Figure 3: Testing WM in the field
melted
Icepacks
WM at discard point
30-40°C, 2 icepacks
30-40°C, 4 icepacks
25-30°C, 4 icepacks
7.2
Melting icepacks
Teams may be confronted with melting icepacks before completion of the campaign.
However, teams must continue immunizing, until:
•
they have finished the work; or
•
the WM has reached the discard point, whichever is shorter.
Teams need to be told to cool the vaccines by whatever means at their disposal:
•
replace the lid immediately after removal of a vial;
•
wrap vials and/or the vaccine carrier in a wet cloth;
•
keep the vials out of the sun at all time;
•
put vaccine carriers in a windy spot;
•
trainers need to insist that health workers use their own creativity to cool the
vaccines.
Every degree the temperature of the vaccines is brought down will
considerably decrease the risk of damage due to heat. When these precautions
are respected, the teams can finish immunizing their target population before the
vaccine is irreversibly damaged.
12
Making use of Vaccine Vial Monitors
7.3
Vials at the end of the campaign or session
•
If OPV vials are opened, but with doses left at the end of a session, they can
be safely used for subsequent sessions, as long as the WM is good and the vial
is not obviously contaminated. To prevent contamination opened vials should
not be submerged under water.
•
Vials of which the WM has started to change colour, without reaching the
discard point, should be kept frozen and used in nearby areas during the
beginning of the next round, or during the routine programme.
•
Unopened OPV vials, whose VVM has not reached the discard point,
should be brought back and stored properly to be used for the following round,
or for the routine EPI.
•
If there is no ice left for the return trip, the vaccines needs to be kept as cool
as possible as described above. The stock manager will decide whether the
vaccine can be used for following activities, using the WM as a management
decision tool.
7.4
What to do in case of shortages/surpluses
In case of shortages of equipment there are alternative strategies to think of.
The WM allows more flexibility.
7.4.1 Shortage of storage capacity for OPV at -20° C
•
Store OPV in cold boxes before the NIDs, while regularly renewing the
icepacks.
•
Store vaccine in refrigerators instead of freezers shortly before the NIDS,
provided the WM has not yet started changing colour
7.4.2 Shortage of vaccine carriers
•
Any other type of non-metallic container can be used to transport the vaccines.
•
Vaccine carriers from neighbouring counties/districts can be borrowed.
•
Use the vaccine carrier as distribution point, from where a few teams can
undertake trips to small remote villages for a few hours. Any type of non
metallic container can be used.
7.4.3 Shortage of cold boxes
•
Use a cold box for more teams: calculate or take a cold box to find out how
many icepacks and vaccines it can contain.
•
Send the teams only vaccine carriers and no cold box, even to the remote
areas. Re-supply with ice if necessary.
WHO/V&B/00.14
13
7.4.4 Shortage of icepacks
•
Use the icepacks of the cold box for the vaccine carriers. If you use this option,
make sure the icepacks of the cold box fit in the vaccine carrier.
•
Put fewer icepacks in a carrier.
•
Use plastic bags to freeze water, but prevent OPV to be floating in water.
7.4.5 Shortage offreezing capacity
•
Store OPV in refrigerators instead of freezers to liberate capacity.
•
Start freezing in advance and store frozen icepacks in cold boxes.
•
Ask neighbouring counties/districts to freeze icepacks for you.
•
Use domestic freezers to freeze icepacks.
•
Ask the private sector (restaurants, fish and ice factories) to make freezing
capacity available.
•
Apply all possibilities given under ‘Shortage of icepacks’.
7.4.6 Shortage/surplus of vaccine
Remote areas can usually not, or only with great difficulty, be re-supplied
with vaccine during the NIDs. In addition, their population size is often only known
with a large margin of uncertainty. To prevent a shortage and interruption of the
campaign, it is crucial the teams in these areas receive additional vaccine from the
start.
For all areas it is equally crucial that the handling of surplus vaccine be dealt with
in the initial planning.
Vaccine quantities distributed during the second round must be based on the
evaluation of the first round.
14
Making use of Vaccine Vial Monitors
Annex 1:
WM Fact sheet
For a cheaper and more flexible cold chain during NIDs
Oral Polio Vaccine is the most heat sensitive of all EPI vaccines. However,
cumulative heat exposure of OPV can now be monitored with the help of the
vaccine vial monitor (WM)i which indicates if a vial can still be used.
OPV, supplied by WHO pre-qualified manufacturers, retains satisfactory potency
for 48 hours at 37°C continuous ambient temperature. The WM reaches the point
where OPV should be discarded (the discard point) before that.
At 25°C ambient temperature the WM reaches the discard point after seven days.
The WM
Inner square is lighter than outer ring.
USE the vaccine, if expiry date not reached.
As time passes: Inner square is still lighter than
outer ring.
USE the vaccine, if expiry date not reached.
Discard point: Inner square matches the colour
of outer ring.
DO NOT use the vaccine.
Beyond the discard point: Inner square is
darker than outer ring.
DO NOT use the vaccine.
Therefore, the WM allows concluding at any time if OPV can be used in spite of
possible cold chain interruptions. Health staff and management can act accordingly
with corrective measures if required.
Besides these corrective actions, the WM can be used pro-actively to plan a more
flexible and cheaper cold chain, which is of particular importance during NIDs.
WHO/V&B/00.14
15
OPV can be safely used beyond the cold chain until the WM reaches the discard
point. The length of time depends on the ambient temperature and the quality of the
cold chain till that point.
The advantages of the use of WMs during NIDs are:
•
teams can go further in time as well as geographically^ due to less bulky
equipment and decreased dependence on re-supply of ice. Difficult access and
weak cold chain cease to be reasons not to immunize population groups
usually missed during nids and the routine services
•
decreased burden of the cold chain: less freezing, smaller quantities of equipment
•
decreased cold chain costs due to these factors.
The WM must be pro-actively integrated in the NID planning:
•
teams returning daily to vaccine distribution points do not need frozen
icepacks (some managers may decide to give one icepack per day merely for
the ease of mind of the teams)
•
teams staying away longer do not have to be supplied with ice for the full
length of their absence
•
all teams must be clearly instructed that the absence of ice is not a reason to
interrupt immunization.
Experience in numerous countries has now convincingly confirmed the advantages
of the WM.
The potential benefits of the WM during the NIDs highly depend on the quality
of the cold chain before that.
Proper storage and transport of opv is vital at all levels.
To gain confidence, EPI managers are encouraged to test WMs in their own region.
To convince health workers of the merits, vials with WMs must be brought to
NIDs training workshops.
16
Making use of Vaccine Vial Monitors
The Department of Vaccines and Biologicals was established by the World Health
Organization in 1998 to operate within the Cluster of Health Technologies and
Pharmaceuticals. The Department's major goal is the achievement of a world in
which all people at risk are protected against vaccine-preventable diseases.
The Department replaces the former Global Programme for Vaccines and
Immunization. Five teams implement its "bench-to-bush” strategy, which starts with
the establishment of norms and standards, focusing on major vaccine and technology
issues, and ends with implementation and guidance for vaccination programmes.
The work of the teams is outlined below.
The Quality Assurance and Safety of Biologicals Team ensures the quality and safety
of vaccines and other biological medicines through the development and
establishment of global norms and standards.
The Vaccine Development Team coordinates and facilitates the development of new
vaccines and immunization-related technologies.
The Vaccine Assessment and Monitoring Team assesses strategies and activities
for reducing morbidity and mortality caused by vaccine-preventable diseases.
The Access to Technologies Team endeavours to reduce financial and technical
barriers to the introduction of new and established vaccines and immunizationrelated technologies.
The Expanding Immunization Team (EPI) develops policies and strategies for
maximizing the use of vaccines of public health importance and their delivery. It
supports the WHO regions and countries in acquiring the skills, competence and
infrastructure needed for implementing these policies and strategies and for achieving
disease control and/or elimination and eradication objectives.
For further information please contact:
Department of Vaccines and Biologicals
World Health Organization • CH-1211 Geneva 27 • Switzerland
Fax: +41 22 791 4192/93 • E-mail: vaccines@who.ch
or visit our web site at:
http://www.vaccines.whb.int/
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