Recommended Injection Sites for Administering Multiple Vaccines

General Principles for Multiple Vaccine Administration

The Centers for Disease Control and Prevention recommends that vaccines administered simultaneously should be given at separate anatomic sites to prevent local reactions from overlapping 1, 2
The FDA states that injectable vaccines given concomitantly should never be mixed in the same syringe unless specifically approved for mixing by the FDA 3
The Centers for Disease Control and Prevention suggests that vaccines that are more likely to cause local injection site reactions should be administered in different limbs when possible 1, 4

For infants under 12 months, the American Academy of Pediatrics recommends that the anterolateral aspect of the thigh provides the largest muscle mass and is the primary recommended site 5, 2
For toddlers and older children, the Centers for Disease Control and Prevention recommends that the deltoid muscle can be used if muscle mass is adequate 2, 7
For adults, the Centers for Disease Control and Prevention recommends that the deltoid muscle is recommended for routine intramuscular vaccinations 6, 7

The Centers for Disease Control and Prevention recommends that when administering vaccines with increased reactogenicity, they should be given in different limbs from other vaccines 1, 4
The Centers for Disease Control and Prevention suggests that the location of each injection should be documented in the person's medical record 7, 8
The Centers for Disease Control and Prevention states that if two live vaccines are not administered simultaneously, they should be separated by at least 4 weeks 1

The Centers for Disease Control and Prevention recommends avoiding administering multiple vaccines too close together in the same limb, as this can cause overlapping local reactions 2, 7
The Centers for Disease Control and Prevention suggests avoiding using the same limb for vaccines known to cause more significant local reactions 1, 4