Larger patients may need to be vaccinated using longer needles in order to get the immunological benefit of the vaccine without local side effects, a researcher reports.
Dr Jane Zuckerman (academic centre for travel medicine and vaccines, Royal Free and University College medical school, London) says that insufficiently long needles may result in subcutaneous rather than intramuscular injection. This could result in lower induced immunogenicity and a higher likelihood of adverse reactions.
Commenting on recent research, Dr Zuckerman says that it may be safer to use a 1in (25mm) needle for men weighing 59-118kg and women weighing 60-90kg, and that women weighing over 90kg may need a 1.5in (38mm) needle (British Medical Journal 2000;321:1237).