Measuring injection-site pain associated with vaccine administration in adults: a randomised, double-blind, placebo-controlled clinical trial.
BACKGROUND
Pain at the injection site is one of the most commonly-reported local reactions associated with administration of a vaccine, but it has not been quantified by a validated instrument for pain measurement. We conducted a randomised, double-blind clinical trial to evaluate the measurement characteristics of two commonly-used pain questionnaires, the McGill Present Pain Intensity (PPI) and the Brief Pain Inventory (BPI) Current Pain Question, in the assessment of intramuscular injection-site pain associated with vaccine administration. The PPI measures pain on a scale of 0 (no pain) to 5 (excruciating pain) and the BPI measures pain on a scale of 0 (no pain) to 10 (pain as bad as you can imagine).


METHODS
Two hundred healthy adults were randomised to one of the five regimens: tetanus and diphtheria toxoids adsorbed (Td), aluminum hydroxide adjuvant (alum), physiological saline, or one of the two licensed hepatitis A vaccines, VAQTA, or HAVRIX. Pain assessment was made at eight time-points over a 2-day period after injection.


RESULTS
The differences in the time-averaged pain (+/- standard deviation) on the PPI were statistically significant between Td (0.58+/-0.59) and either saline (0.14+/-0.23) (p < 0.005) or alum (0.22+/-0.35) (p < 0.01). Reported time-averaged pain were significantly lower for VAQTA than HAVRIX (p = 0.028). Similar differences were observed for the BPI.


CONCLUSIONS
Both instruments have sufficient discriminative validity to distinguish between different levels of injection-site pain in adults.
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Department of Epidemiology, Merck Research Laboratories, West Point, PA 19486-0004, USA.
Tucker
R
R
Frey
S E
SE
Gress
J O
JO
Chan
I S
IS
Kuter
B J
BJ
Guess
H A
HA
D000293:Adolescent; D000328:Adult; D000368:Aged; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007267:Injections / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000145:classification / Q000453:epidemiology* / Q000209:etiology; D010147:Pain Measurement / Q000379:methods* / Q000592:standards; D010919:Placebos; D014481:United States / Q000453:epidemiology; D014611:Vaccination / Q000009:adverse effects*
D010919:Placebos