Device contains one needle, a reservoir for vaccine, and a reservoir for blood. The blood test is taken first, then the vaccination is injected using the same needle. Cross-contamination is not a concern; the needle can be mechanically designed to prevent the vaccine from contaiminating the blood. Contaminating the blood with the vaccine doesn't matter since it will be "contaminated" once injected anyhow.

Benefits:

1. Fewer injections means happier patients.

2. People who refuse vaccination due to hatred of needles will be more willing to get vaccinations since the needle is already there. "While the needle is there, should I vaccinate you?" vs. "Can I poke you with a needle twice instead of once?"
-- aguydude, Feb 16 2012

US patent 2564977 http://www.google.com/patents/US2564977
... it is a primary object of the invention to provide an easily operable medical device which permits simultaneous extraction of fluid of one kind from the body and simultaneously injecting a fluid of another kind into the body. [xaviergisz, Feb 16 2012]

for [Ling] - lots of scrolling... http://www.cdc.gov/...es/D/vacc_admin.pdf
[xandram, Feb 16 2012]

Intramuscular vs subcutaneous immunisation Ah, now I undershtt...rticles/PMC1118997/
[spidermother, Feb 16 2012, last modified Feb 28 2012]

Vaccines are injected into the muscle, not the vein. Other than that one amusingly disastrous flaw in the concept, I see no reason why this wouldn't work.
-- Alterother, Feb 16 2012


Yeahbut ... this is perfect for clumsy phlebotomists and cash-strapped hospitals interested in upselling: "Oops, I missed the vein, but, not to waste the opportunity, for an extra $1.98, I can give you a tetanus booster."

Also useful for Nosferatu reenactors.
-- mouseposture, Feb 16 2012


//prevent the vaccine from contaiminating the blood. Contaminating the blood with the vaccine doesn't matter// sp. Contaminating the vaccine with the blood doesn't matter.
-- spidermother, Feb 16 2012


// Vaccines are injected into the muscle, not the vein.//

Anyone care to explain why?
-- Ling, Feb 16 2012


link for you [Ling]
-- xandram, Feb 16 2012


Thanks.
Finally found it....
//Many inactivated vaccines contain an adjuvant, which is a vaccine component that enhances the immune response to the antigen. Adjuvants can cause an exaggerated local reaction (e.g., pain, swelling, redness) if not injected into the muscle//

So it can be done otherwise, but it might be sore, right?
-- Ling, Feb 16 2012


That explanation seems incorrect. //Many inactivated vaccines contain an adjuvant, which is a vaccine component that enhances the immune response to the antigen.// is correct, but I would think that intramuscular injection is precisely in order to create a local reaction; that is, the antigen and the enhanced immune response caused by the adjuvant need to be localised in the same muscle region.
-- spidermother, Feb 16 2012


//Vaccines are injected into the muscle, not the vein.//

//Anyone care to explain why?//

Interesting question. From a quick internet search it seems to be so the vaccine can slowly diffuse into the body. If you injected into the vein it would be either be: a) immediately filtered through your liver or b) a dangerous shock to your system, depending on the vaccine.
-- xaviergisz, Feb 16 2012


Ah, now I understand Ling's annotation better. Intramuscular injections create less pain and irritation than *subcutaneous* (not intravenous) injections (link).

Also, From Wikipedia:

"Third, adjuvants help to increase the capacity to cause local reactions at the injection site (during vaccination), inducing greater release of danger signals by chemokine releasing cells such as helper T cells and mast cells.",

which would appear to support the need for localised, i.e. subcutaneous or (better) intramuscular, rather than systemic, i.e. intravenous, injection.
-- spidermother, Feb 16 2012



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