RESUMO
Objectives To compare vaccine related reactogenicity during primary immunization in healthy infants using 23 vs. 25 gauge needles. Methods This randomized controlled trial was conducted in Vaccination Room of the Advanced Pediatrics Center. 155 participants for primary immunization were assigned to two intervention groups (23 vs. 25 gauge). Parent-reported local and systemic reactions were recorded daily for three days after the immunization. Results Swelling (24%) and tenderness (21%) were the two most common parent-reported local symptoms followed by restriction of movements (18%) and redness (10%) on day 1. Any local reaction on day 1 was statistically similar in 25 gauge vs. 23 gauge group (RR 0.77; 95%CI: 0.32 to 1.82) (P= 0.54), but fever (day 1) showed higher trend in 23 gauge needle group (RR 2.24; 95% CI: 0.92–5.47) (P=0.07). Furthermore, on analysis of serially reported local and systemic reactions for 3 consecutive days by generalized estimating equations, odds of redness, swelling, tenderness, restricted movement and fever were statistically similar between two needle groups. On the other hand, median (±SE) crying time (in seconds) was significantly prolonged in the 25 gauge needle (39±2) as compared to 23 gauge group (30±1.3) (log rank test, P=0.001). Conclusions The use of same length needles with narrower (25) or wider (23) gauge did not show significant differences in local reactogenicity during primary immunization. Fever, however, was reduced marginally in 25 gauge group whereas crying duration was significantly shorter with 23 gauge needle. Finally, larger studies are needed to further evaluate objectively the outcome of reactogenicity.