I just got my HepB updated an Tdap in my R and L arms and the lady who did mine was awesome. I made sure my muscles were relaxed, and she darted me and injected the vaccine. Could hardly feel it. Less time in the muscle the better. As long as they're not emaciated I don't see a reason not to dart them. It's not like your inserting the needle to the hub, so I unintentional intrathecal injection is rare.
I would even go as far to say don't even worry about aspirating in the deltoid in a healthy individual if you know your landmarks, because there is no major arterial supply on the lateral deltoid and the gauge of the needle is too small for serious concern of arterial infiltration.
Current evidenced based (CDC's on board with this) practice and IAC (immunization action coalition) actually suggest it is best practice NOT to aspirate for vaccinations: IAC Express Issue 891
Last edit by mrmedical on Aug 14, '12
: Reason: spellcheck