Administering COVID-19 vaccines to individuals at extremes of bodyweight

Anna Bischler, Lead Medicines Information Pharmacist, Midlands and East Medicines Advice Service (East site)Published Last updated See all updates

Information on vaccine administration and priority schedule for individuals at extremes of bodyweight. Applies to all vaccines.

Morbidly obese

Public Health England advise that longer length (38mm) needles are used for morbidly obese individuals to ensure the vaccine is injected into muscle. These can be requested when ordering the vaccine if required in addition to the 25mm needles and syringes that will be supplied.

The Joint Committee on Vaccination and Immunisation have identified morbid obesity as an underlying health condition which puts the individual at a higher risk of serious disease and mortality associated with COVID-19. Patients who are morbidly obese are in the vaccination priority group ‘all individuals aged 16 years to 64 years with underlying health conditions which puts them as higher risk of serious disease and mortality’. Public Health England’s Immunisation Against Infectious Disease (The Green book) defines morbid obesity as adults with a Body Mass Index ≥40 kg/m².

Low bodyweight

Public Health England advise that for individuals who have minimal muscle mass in the deltoid area of the upper arm, or who have a particular reason to avoid immunisation in the deltoid muscle, their vaccine may be given in the vastus lateralis muscle in the thigh if necessary.

Public Health England’s Immunisation Against Infectious Disease (The Green book) states that individuals under a certain weight is not a contraindication to routine immunisation. The Summary of Product Characteristics (SPC) for the Pfizer-BioNTech vaccine does not list an extreme of body weight as a contraindication nor as a special warning or precaution for use. The MHRA Information for Healthcare Professionals for the AstraZeneca COVID-19 vaccine does not list an extreme of body weight as a contraindication nor as a special warning or precaution for use.

Change history

  1. Link to the SPC for the Pfizer-BioNTech vaccine (Comirnaty) provided in place of the MHRA Information for Healthcare Professionals.
  1. Published