Post0216 INJECTION SAFETY 12 January 2000
CONTENTS
1. NEW SAN FRANCISCO CHRONICLE ARTICLE: REPLY TO COMMENTS
2. STERILITY TESTING - PROCESS CONTROL VERSUS PRODUCT CONTROL
3. INJECTION DEVICE ENVIRONMENTAL LIABILITY?
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1. NEW SAN FRANCISCO CHRONICLE ARTICLE: REPLY TO COMMENTS
In TECHNET Post0215, Injection Safety, on 11 January 2000, the New San
Francisco Chronicle Article: "Global Push For Safe Needles: Agencies want
to curb spread of deadly viruses" by William Carlsen was posted along with
comments and corrections from Gordon Larsen, WHO/V&B.
In todays posting, Bill Carlsen, SF Chronicle, replies.
It is in all of our interests to get the correct and accurate story out.
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From: William Carlsen
To: "'Technet Moderator'"
Subject: RE: Post0215 INJECTION SAFETY
Date: Tue, 11 Jan 2000 11:18:37 -0800
Dear Allan:
Thanks for posting our article "Global Push for Safe Needles" (Post 0215).
I welcome any comments or corrections. I was a little perplexed, however,
by the corrections from Gordon Larsen of WHO. He states that there is "no
plan to phase out all sterilizables by the end of 2003." I went back to
look at the Joint Statement of WHO/UNICEF/RED CROSS AND RED CRESCENT
SOCIETES posted on Technet on November 8, 1999 (Post 203) and found a
different statement. In that statement, it says under (4) that WHO and
UNICEF "urge that by the end of 2001 all countries should use only
auto-disable syringes or sterilisable syringes. Standard disposable
syringes should no longer be used." That statement is followed by: "WHO
and UNICEF urge by the end of 2003, all countries should use only
auto-disable syringes for immunization."
I'm confused by Mr. Larsen's statement that I have somehow reported this
inaccurately. Maybe I'm missing something and I don't understand the joint
statement. I thought I was giving it a straightforward interpretation. I
welcome any comment from Mr. Larsen or any one else that could straighten
this out for me. Clearly what Mr. Larsen says and what the joint statement
says seem to be at odds.
Meanwhile, I stand corrected on the number of A-Ds produced in 1999 at 150
million and not the 100 million figure that I reported, which was the
estimate given me by both Beckton Dickenson and Univec. It is indeed
encouraging that A-D manufacturing capacity will be 500 million in 2000.
But that is capacity. What about actual production? Mr. Larsen notes that
in 1999 the capacity was 300 million but only 150 million were produced.
Again thanks for any comments and corrections. I strive to be as accurate
as I can in my reports.
Yours,
Bill Carlsen,
The San Francisco Chronicle
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2. STERILITY TESTING - PROCESS CONTROL VERSUS PRODUCT CONTROL
Sterility testing for the processing of injection equipment was discussed
in TECHNET Post0205, INJECTION SAFETY, 12 November 1999, in the context of
the decision of the West Bengal, India, Government to stop using disposable
injection equipment and return to sterilizables.
In post0205, item 3. Sterility testing of disposable syringes & needles
marketed in Calcutta, a long running discussion between Anthony Battersby,
FBA Health Analysts, and Joel Schoenfeld, UNIVEC, a manufacturer of A-D
syringes, the TECHNET Forum posted a 1998 paper by M Pal in the Indian
Journal of Public Health: Sterility Testing of Disposable Syringes and
Needles Marketed in Calcutta (IJPH, Vol:XXXXII, No.4, Oct-Dec 1999.
Peter Hoffman, UK Public Health Laboratory Service, prepared this
discussion of the thinking in the United Kingdom on the use of sterility
testing in sterilization processing.
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Date: Sat, 27 Nov 1999 08:50:54 -0500
From: Anthony Battersby
Subject: STERILITY TESTING - PROCESS CONTROL VERSUS PRODUCT CONTROL
To: [[email protected]][email protected][/email]
Dear Allan,
Following the piece on "unsterile" disposables in Calcutta, I contacted
Peter Hoffman at PHLS and asked him for his views on the merits of trying
to carry out aseptic testing. He has written the following for Technet.
Anthony
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STERILITY TESTING - PROCESS CONTROL VERSUS PRODUCT CONTROL
There is an excellent analysis of this topic following an incident where
inadequately sterilized infusion fluid was distributed throughout the UK.
It is called "The myth of surgical sterility" Lancet 1972, December 16th,
pages 1301 to 1303 and was written by the Deputy Director of the UK Public
Health Laboratory Service of the time - Jos Kelsey. It has formed the UK
thinking on sterilization quality assurance ever since.
Briefly abstracted, the thinking is as follows:
PRODUCT CONTROL
Even with an experienced operator with good facilities, there is a definite
false positive level when doing sterility tests. The paper gives examples
as a 0.1% operator contamination rate with easy items like ampoules and a
5% rate with more difficult items like dressings (I can vouch for the
latter from personal experience). Depending on the item, facilities and
skill, I think operator contamination rates could well go up to 50% or
beyond. All this makes detecting "real" contamination difficult and, if
contamination is at a low rate, impossible.
Using sterility testing for acceptance/rejection of "sterile" products, the
situation is as follows: The paper gives the example that, statistically,
if 20 random samples are taken from a batch that is 10% contaminated, there
is a 1 in 8 chance that all samples (without operator contamination) will
be sterile and the batch accepted. If 5% contamination, there would be a 1
in 3 chance of acceptance. As the sample size goes up, the testing gets
more accurate, but the problem with false positives gets worse.
There is the additional problem that several recovery media would be needed
to grow most, but not all, bacterial contaminants. This would increase
manipulation and consequent operator contamination.
PROCESS CONTROL
We know from laboratory work, what conditions are required to kill what
levels of what contaminant. Microbes die straight-line semilogarithmically
- i.e. exposed to something they don't like 9 out of 10 will die in a given
unit of time - this means a 10-fold reduction. In a further unit of time
exposed to the same conditions, a further 9 out of 10 will die. This is,
under given conditions, "the decimal reduction time". Say 1,000,000 (10 to
the power six) bacterial spores of a species that has a decimal reduction
time of 1/2 a minute when exposed to steam at a certain temperature. In 30
seconds they will be reduced to 100,000; in one minute to 10,000; in three
minutes to 1. In three and a half minutes to 0.1 - a tenth of a spore does
not exist, but is also one tenth the chance of a spore surviving or one
spore surviving in every ten batches put through the process. In this
example, after six minutes, the spore level will be down to 0.000 001 (10
to the power minus six) - one millionth the chance of a spore surviving.
This safety margin is not something that can be detected by culture.
The conclusion from this argument is that sterility testing has a severely
limited place in production or monitoring of sterile items. It is the
process that needs monitoring.
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3. INJECTION DEVICE ENVIRONMENTAL LIABILITY?
This is a follow-up to a discussion on potential for the extension of
product liability legislation to injection devices - to cover their safe
use eventual safe disposal. Comparisons were mad with the changing status
of firearms and tobacco products in countries such as the USA.
In Post0160 INJECTION SAFETY on 21 June 1999, Anthony Battersby, FBA, and
Allan Bass, ACITHN, discussed issues of legal liability and negligence in
relation to the unsafe use and the provision of of injection equipment. and
asked: "Does anyone know what the legal position is?"
In post0171, 2 August 1999, Janine Jagger, International Health Care Worker
Safety Center at the University of Virginia Medical School, offered a few
thoughts on the complexities of the legal environment.
In today's posting, Anthony notes that regulations, requiring motor vehicle
manufacturers liable for the ultimate disposal of their product.
It should be noted that some countries (Switzerland) already requires the
inclusion of cost of environmentally safe disposal in the purchase price of
computer equipment.
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Date: Thu, 16 Dec 1999 11:15:39 -0500
From: Anthony Battersby
Subject: Injection safety
To: [[email protected]][email protected][/email]
Dear Allan,
The EU is in the process of passing legislation that will make motor
manufacturers liable for the disposal and destruction of the motor vehicles
which they manufacture. This will be fully implemented by 2006 and begins
in 2001. So if car makers are to be liable for their products why not
syringe manufacturers?? Ref: David Brown "Thousands of Cars left to rust by
the roadside" Independent on Sunday pp 10 12 December 1999
Thanks,
Anthony
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