Effect of needle length when immunizing obese adolescents with hepatitis B vaccine

Pediatrics. 2010 Mar;125(3):e508-12. doi: 10.1542/peds.2009-1592. Epub 2010 Feb 8.


Objective: Several studies have noted that obese adolescents and adults achieve lower titers of antibody in response to vaccines such as hepatitis B virus (HBV) vaccine. The objective of this study was to determine whether use of a longer (1.5-in) rather than a standard (1-in) needle to penetrate the thicker deltoid fat pad among obese youth would result in higher antibody titers after immunization against HBV.

Methods: Obese adolescents from a large metropolitan area who had not previously received the HBV vaccine were randomly assigned to be immunized with HBV vaccine by using either a 1-inch or a 1.5-inch needle.

Results: Those who were immunized with a 1.5-inch needle achieved significantly higher antibody titers to hepatitis B surface antigen (median titers: 1-inch = 189.8 mIU/mL, 1.5-inch = 345.4 mIU/mL; P = .03).

Conclusions: This finding supports the hypothesis that needle length accounts for a significant portion of the discrepancy in immune response to HBV vaccine that is seen among those with obesity.

Publication types

  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Equipment Design
  • Female
  • Hepatitis B Antibodies / blood*
  • Hepatitis B Vaccines / administration & dosage*
  • Hepatitis B Vaccines / immunology*
  • Humans
  • Male
  • Needles*
  • Obesity*
  • Young Adult


  • Hepatitis B Antibodies
  • Hepatitis B Vaccines