Little research regarding appropriate immunization administration technique for adults has been carried out. Pain
is a leading cause of self-deferral from immunizations. The purpose of this study was to determine whether administering intramuscular injections using cold needles would decrease patients' perceived pain
and have an effect on the immune response elicited by the vaccine.
Eighty participants received an injection
vaccine in 1 arm and a saline injection
in the other using a cold or room temperature
needle in a double-blind fashion assigned at random. Participants rated their pain
after each injection
using a standard visual pain
scale bounded by no pain
and most painful injection
ever. Vaccine antibody response was measured using hemagglutination inhibition assays.
scores after influenza
vaccine administration were quite low (34.2±2.5 mm). The mean pain
score for influenza
vaccine was not different using cold or room temperature
needles (cold 32.2 mm±3.20 vs. room temperature
36.0 mm±3.80; t
=0.450). The mean pain
scores for saline injections did not differ (room temperature
23.7 mm±3.19 vs. cold 25.2±2.95; t
=0.73). Individuals receiving injections with cold needles had less bruising (0/40 vs. 5/40; P
<0.02) at the injection
site, but incidences of pain
and erythema were similar. The use of cold needles for vaccine administration had no effect on antibody response.
vaccine administration is generally mild. Use of cold needles may not be worth pursuing for injections associated with mild pain
. However, it may be worthwhile to explore using cold needles as an analgesic with more painful injections.