Evaluation of Needle Length and Hepatitis B Vaccine Response in Correctional Personnel in Massachusetts

Abstract

A hepatitis B vaccine program was offered to personnel in 21 Massachusetts prison facilities beginning in August 1992. Current literature recommends that hepatitis B vaccine be administered into the deltoid muscle with a 1 inch or 1.5 inch needle. Nearly 1600 officers and 200 medical staff were immunized. When it was discovered that some institutions had used a 5/8 inch or one inch needle to administer the vaccine into the deltoid muscle, hepatitis B surface antibody testing was offered to vaccinated staff. A positive vaccine response was defined as a sample ratio unit (S/N ratio) equal to or greater than 10. Institutions were classified based on the shortest needle used. Response rates were analyzed by needle length group and by age when available. Of the 225 individuals who had antibody determinations, 166 (74%) had adequate levels of antibody. When analyzed by needle length, no statistically significant difference in response rates was noted. When analyzed by ten-year age groups, the youngest age group (20-29) had the highest vaccine response (85%); and vaccine response decreased with increasing age. Our observed vaccine response rate of 74 percent may be an underestimate because exact time interval since third dose was not available by individual, but was known to be greater than six months for some individuals. There was no observed effect of needle length on immune response. We did observe decreasing immune response with increasing age. We recommended that only 1.5 inch needles be used for intramuscular injections.