Needle Length May Affect Vaccination Results in Obese
by -- Eric Metcalf Updated: Feb 9th 2010
TUESDAY, Feb. 9 (HealthDay News) -- The reduced immune response seen in obese adolescents and adults following hepatitis B virus (HBV) vaccination may be due in part to insufficient needle penetration of muscle, according to research published online Feb. 8 in Pediatrics.
Amy B. Middleman, M.D., of the Baylor College of Medicine in Houston, and colleagues analyzed data from 24 teens and young adults, aged 14 to 24 years. Females weighed more than 90 kg and males more than 120 kg. Subjects were randomized to receive their HBV vaccination series with a 1- or 1.5-inch needle.
The researchers found that subjects vaccinated with a 1.5-inch needle had significantly higher antibody titers to HBV surface antigen compared to the 1-inch-needle group (345.4 versus 189.8 mIU/mL).
"Despite the small sample size, obese adolescents and young adults achieved significantly higher titers of anti-HBs after HBV vaccine when a 1.5-inch needle was used for administration rather than a 1-inch needle. This supports the hypothesis that inadequate muscle penetration is responsible, at least in part, for lower immune response to HBV vaccine among obese adolescent and adult vaccine recipients," the authors write.
