The importance of injecting vaccines into muscle
A standard size needle does not guarantee successful administration of vaccines in all people, especially for patients over a certain weight, according to an editorial in this week's BMJ.
Jane Zuckerman, a senior lecturer at the Academic Centre for Travel Medicine and Vaccines, Royal Free and University College Medical School in London, reports on a recent study involving 220 adults receiving vaccinations. It found that a standard 5/8 inch (16mm) needle could not penetrate the upper arm muscle in 17% of men and nearly 50% of women because of a wide variation in the thickness of the fat pad above this muscle. The study recommended that for men weighing 59-118kg and women of 60-90kg it may be safer to use a 1 inch (25mm) needle, and women over 90kg may need a 1.5 inch (38mm) needle.
It is essential that vaccines reach the muscle to ensure that the body's immune response is triggered and to reduce the likelihood of an adverse reaction, says the author. A selection of needles should be available to allow healthcare professionals to select a length and gauge of needle appropriate to each patient, she concludes.
Contact:
Jane Zuckerman, Senior Lecturer, Academic Centre for Travel Medicine and Vaccines, Royal Free and University College Medical School, London, UK
Email: j.zuckerman@rfc.ucl.ac.uk