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Does cleaning syringes work?
There is now convincing evidence that cleaning syringes with water and bleach will kill ALL of the blood-borne virus in 99.9% of syringes.

This short documentary talks to the research team who conducted the research on the impact of bleach on HIV on syringes, and explains why it is so important that syringe cleaning is taught to injecting drug users.

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This film can be viewed on YouTube (click on the link above), and is available now on the the Harm Reduction Works film collection.

Syringe Cleaning Frequently Asked Questions:

Doesn’t teaching people to clean syringes detract from the central message
of ‘always use a new, sterile syringe?’


The message of 'where possible, always use a new clean sterile syringe' is
still central to the task of blood borne virus transmission prevention.

However, we know that injectors may not have sufficient needles and
syringes with them and so, sensibly, they do take steps to clean their
equipment rather than purposely using dirty ones; and those who do not
clearly could benefit by doing so.

Is one rinse enough to clear all the bleach from the syringe?


The volume of bleach in the syringe when it’s emptied is much less than
100th of a millilitre... so the bleach concentration when the syringe is
refilled with the water is less than 1 part in 100. But even then the
syringe contents are expelled to leave less than the 100th millilitre of 1
part in 100 concentration bleach in the syringe. Then that dilute solution
of bleach is diluted even further when the syringe is again filled with
another ml of fluid (ie the drug + water), so diluting it again by a factor
of around 100 prior to injection!

There has been no identified risk from using such a tiny amount of bleach,
but by contrast there is a high risk of life threatening blood borne virus
infection from syringes that aren’t properly cleaned.

What is ‘thin bleach’?
In the UK bleach with added thickeners is often used for cleaning toilets
because it’s claimed to stick better under the rim of the toilet.

Thickened bleach has the same virus-killing cleaning effect on syringes as ‘thin bleach’ but
it is much more difficult to draw thickened bleach into an insulin syringe
with an attached needle and so is not recommended.

Can you dilute thick bleach with water to make it thin?
You could, but it would probably reduce it’s virus-killing effect - so it
is far better always to buy, to use and to have thin bleach available.

Once injectors have realised why, it should be very easy to get into the habit
of obtaining and using thin bleach.

Why don’t the instructions make it clear that you shouldn’t use thick

Although it’s difficult to draw thick bleach into an insulin syringe, you can use thick bleach when cleaning a Luer slip syringe with detachable needles. Without a really good reason to do so, we didn't want to say 'don't' to anything that might be useful in exceptional circumstances.

Saying no completely to ever using thick bleach, for example when thin is not available, is not really scientifically sound as it can works well, and has the same virus-killing effect in larger syringes.

Also, a complex 'yes to x but no to y' message potentially adds confusion in this sort of medium, to an otherwise clear health message. In time people can forget exactly what it was they were told they should, and what it was they were told they shouldn’t do - so keeping the message as simple as 'Use thin bleach' has definite advantages.

The evidence says that the more complicated the instructions, the less likely people are to follow them, so great care must be taken when adding complexity to health messages.

Shouldn’t you use boiling water to rinse the syringe?

It has actually been suggested that boiling water could scald the blood and
cause it to clot and stick on the syringe with a protective coating that
could actually protect live virus beneath it.

Should people only use cold tap water?
Any tap water is normally fine for the process of rinsing – as the hot
water from the hot tap won’t be likely to be hot enough to cause the
suggested clotting effect - and obviously the bleach will kill germs.
In fact, it won't be a surprise that the theoretical optimal type of water
to use for the final rinse is 'cooled-down boiled water', poured from the
kettle, as this is virtually sterile.

But this was considered too complex a message for general distribution in the campaign materials as the reference to boiled water could seem contradictory given the powerful cleansing effect of the bleach.

However, in a 1 to 1 setting it is a good idea for workers to discuss these details with those injectors who seem interested in optimising their cleanliness techniques and who are keen to develop a wider understanding of the issues involved in maximising prevention of
virus and infection spread.

What about the outside of the needle?
The quantities of blood on the outside of the needle are much smaller than
the quantities inside the syringe, and the virus there is more exposed and
vulnerable. The rinsing with water will remove some or all of this blood –
but it still may pose a small infection risk. So, ideally the outside of
the needle should be immersed in bleach during the process but this bleach
also should be carefully washed off.

The cleaning instructions for the campaign are designed to be simple, and
to feel repeatable (work in the US shows that every added step can result
in people not completing any steps, or making mistakes, and the work on the
effectiveness of cleaning equipment as described in the campaign has shown
very good results).

Should the cap be cleaned?
If the dirty needle has been resheathed, the cap should be cleaned too.
Again, the reason this isn’t spelled out in the instructions, is that we
wanted to keep the instructions easy and repeatable. However, this approach
is not intended to inhibit workers who understand the risks discussing them
in detail with clients who are interested – and this is the level of risk
assessment and BBV transmission understanding that we’re aiming for with
injecting drug users.



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