Post00299 VACCINE FREEZING CONTINUED 16 November 2000
CONTENTS
0. MODERATORS NOTE ON VACCINE FREEZING
1. LOW TEMPERATURE PROTECTION: IN TRANSPORT
2. LOW TEMPERATURE PROTECTION: REFRIGERATORS
3. THE USE OF INDICATORS: THE STOPWATCH
4. OTHER THOUGHTS...
The Technet'99 report and presentations are available on the web at:
http://www.who.int/vaccines-
ccess/Restructuring/Vaccines/Vaccine_Quality/Vaccine_Cold_Chain/Technet/199
9Technet.htm
You can also request copies by email to: [[email protected]][email protected][/email]
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0. MODERATORS NOTE ON VACCINE FREEZING
The freezing of Hepatitis B, DPT, DT, TT, Td, and HIB vaccines in the cold
chain are of concern. While these vaccines are relatively heat stable they
are subject to damage by one or more freezing events. Pertussis vaccine
may be affected by supercooling.
Field data collected in a variety of climates and settings has shown that
vaccine freezing events are common occurrences.
More than ten years of frequent field observations by experienced
consultants suggest that the problem is not a minor inconvenient technical
problem BUT IS A LARGE SCALE PROBLEM compromising both the effectiveness of
these vaccines and ultimately the credibility of immunization programs and
the GAVI initiative.
The Technet 1998 report has a section on low temperature protection.
It says that WHO will:
* Develop and circulate draft specs by end 1998
* Guidelines will be drafted comment by end 1998
* Low temperature protected equipment will be incorporated into the
* Performance specs and test procedures
* Manufacturers will be invited to produce equipment
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1. LOW TEMPERATURE PROTECTION: IN TRANSPORT
In todays posting Jaap Dominicus and Menno Goedhart of MSF, ask what data
and experience is available on the safety of vaccine transport in cold
countries.
On a very positive note, they point out that they are ready to invest in
the testing of cold boxes!
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___________________________________________________________________________
Date: Thu, 12 Oct 2000 13:45:43 +0100
From: [[email protected]][email protected][/email] (Jaap DOMINICUS)
Subject: Re: Low Temperature Protection
To: Technet Moderator
Dear Allan,
As we are not completely sure that the transport in cold countries is safe,
we - that is MSF-Holland - would like to post this question to the forum:
* What data and/or experience is available on this subject?
If need be, we are ready to invest in testing cold boxes for low
temperatures.
Could you post this?
Tnx
Jaap Dominicus
Menno Goedhart
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2. LOW TEMPERATURE PROTECTION: REFRIGERATORS
In Technet Post00293, 27 October 2000, and Post00295, 31 October 2000,
proposed specifications for incorporating low temperature protection in
refrigerators for vaccines was discussed. A number of potential solutions
were offered.
* In todays posting Hans Everts, WHO/EPI, and Mogens Munck, UNICEF, discuss
some potential solutions.
* Debbie Kristensen, PATH, points out that there is no global solution:
this must be dealt with country by country.
* The moderator asks:
1. Who is going to do it?
and
2. How is it going to be achieved?
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___________________________________________________________________________
From: [[email protected]][email protected][/email]
Date: Tue, 31 Oct 2000 17:09:23 +0100
Subject: RE: Post00293 FREEZE WATCH INDICATORS, EXPIRY DATES & USE
To: Technet Moderator
Dear Allan,
Within this context it is worth reminding the readers that all
manufacturers have been informed that negative temperatures in
refrigerating compartments will no longer be tolerated. The deadline is
December 2000 and we have already received from several manufacturers the
confirmation that they have solved or are about to solve the problem.
Although this helps, it is still not the perfect solution. Appliances are
tested in a presumed worst case scenario setting with optimum thermostat
setting. The optimum setting is not necessarily the maximum setting and
there is nothing to prevent somebody in the field to put it at whatever
position he/she likes.
Solutions would be: a) make sure that on the thermostat scale the optimum
setting is highlighted.
The risk is that people might use the optimum setting in colder ambient
temperatures, when they should really decrease the setting
b) block the thermostat button at the optimum setting, making it impossible
to go higher. This is however only an option if we are 100% sure the test
conditions are really the absolute worst case scenario.
c) get rid of manual thermostats all together. This is an option already
studied by manufacturers of compression appliances. For gas absorption it
is only possible if a battery is added, which would be a huge disadvantage
and for kerosene it still does not make any difference.
Best regards
Hans Everts
Technical Officer
EPI
WHO Geneva
Tel: 00 41 22 791 3683
---
From: [[email protected]][email protected][/email]
Date: Thu, 02 Nov 2000 16:10:41 +0200
To:
Subject: Re:Post00295 VACCINE FREEZING
Dear Allan and all Technet members,
Enclosed please find my contribution to the on-going discussion of low
temperature protection fridges!
Regards to everybody!
Mogens Munck
P.S. From next week I am back in Spain as my one year assignment with
UNICEF, Maputo, is over. My e-mail address will then again be
[email protected].
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1.11.2000-11-01
To: Allan Bass and all Technet members!
Re.: Discussion on low temperature fridges.
I agree with Michel, the ball was never picked up, but I believe that it
will be picked up - and hopefully successfully - pls. see below!
Next, as Soren Spanner says no need to blame WHO, UNICEF, Vestfrost, and
not even Electrolux, but only ourselves for not having made the
specifications to demand better low protection.
Soren suggests better thermostats, and they will surely help. I suggest
eliminating altogether the need for having risky sub-zero temperatures in
our vaccine fridges in order to freeze ice packs and/or to reconstitute an
ice lining after power failure. How to achieve this? By utilizing
eutectics, either commercial ones or the Glaubers salts suggested by me in
Copenhagen.
On my part I have got UNICEF, Maputo to finance a test of Glaubers' salts
at the CSIR, Laboratory in Johannesburg. CSIR will not only test the
thermal qualities of Glauber's, salts, but also how best to mix huge
quantities and fill hundreds, if not thousands of ice packs with this
eutectic. The testing will probably start next week.
Technet Forum has already last year presented a description of Glaubers
salts. The advantage of Glaubers salts is that it is very cheap to procure
when buying bulk quantities. I hope that Glaubers salts would be ideal for
filling ice packs, while perhaps commercial eutectics with ALL the thermal
characteristics inside the temperature range of 2-10 degrees would be most
appropriate for forming ice linings.
Conclusion: Eutectics could eliminate the need for having dangerous sub-
zero temperatures in our vaccine fridges.
Regards!
Mogens Munck
---
From: "Kristensen, Debra"
To: "'Allan Bass'"
Subject: RE: Freezing vax in 1996
Date: Fri, 27 Oct 2000 13:45:19 -0700
Dear Allan:
Cold chain analysis, training, and temperature monitoring (using whatever
means are available) are probably the keys to this hidden problem.
A magic, global solution is unlikely; we are not going to see a freeze
indicator integrated with a VVM in the near future. I think that this issue
needs to be tackled on a country-by-country basis.
Note: PATH Ukraine hopes to launch a small cold chain study (2-3 Oblasts)
this winter with an emphasis on the risk of freezing.
All the best,
Debbie
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4. USE OF THE STOPWATCH INDICATOR?
Freeze indicators are available, though their use is problematical.
FreezeWatch Indicators were last discussed in Technet Post00293 Freeze
Watch Indicators, Expiry Dates & Use, 27 October 2000.
Serge Ganivet, WHO, asks how the Vaccine Monitor Mark, as incorporated in
the StopWatch refrigerator monitor should be used!
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___________________________________________________________________________
Date: Sat, 28 Oct 2000
To: Technet Moderator
From: Serge Ganivet
Subject: Re: Post00293 FREEZE WATCH INDICATORS, EXPIRY DATES & USE
Dear Allan,
I don't think it is too complicate to find action when a Freeze watch
indicates that a freezing event has occurred. Anthony and yourself give
some
action which could be taken or done. My concern is more about the Stop
Watch Refrigerator Monitor special when the indicators A, B or C becomes
blue.
For Example, in a health center I install a Stop Watch Monitor in a vaccine
refrigerator the 1st sept'00. After few weeks A becomes blue, OPV should be
used within 2 months, measles etc. but in October the EPI responsible
receives a new stock of vaccines (OPV, Measles, etc.). How can I manage the
different stocks of vaccine. It is absolutely not clear for me.
Thank you for your contribution,
serge
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4. OTHER THOUGHTS...
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___________________________________________________________________________
Date: Wed, 01 Nov 2000
To: Technet Moderator
From: Ian Neering
Subject: Re: Post00295 VACCINE FREEZING
Here's a couple of lay questions from someone who knows nothing.
Can we assume that it's the act of freezing per se rather than low
temperatures which causes vaccine damage?
If so, why not simply add some antifreeze of appropriate type to the
vaccine formulation?
I'm sure I'll be bombarded with a dozen good reasons why this can't be done
but thought I'd throw in my two cents worth!
Ian Neering
---
From: [[email protected]][email protected][/email]
Date: Fri, 27 Oct 2000 09:37:45 EDT
Subject: Vaccine Freezing
To: [[email protected]][email protected][/email]
Allan,
Where does the problem of vaccine freezing occur? Is it mostly in northern
countries and is due to cold winters? Or is it in the warm countries and is
due to temperature control in the fridge?
Thank you,
Carl Erickson
---
Allan Replies: All of the above and more in all climates!
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