Seasonal Influenza Vaccine Dosage & Administration

Preparing for vaccine administration

CDC recommends only preparing and drawing up vaccines just prior to administration. General-use syringes are designed for immediate administration—not for storage. Contamination and microorganism growth can occur in syringes with predrawn vaccine, especially with vaccine that does not contain a preservative. In addition, vaccine components may interact with polymers in a plastic syringe over time, potentially reducing vaccine potency.

As an alternative to predrawing vaccines, CDC recommends using manufacturer-filled syringes for large vaccination clinics.

However, if vaccine must be predrawn:

• Do not draw up vaccines before arriving at the clinic site. Drawing up doses days or even hours before a clinic event is not acceptable.
• Each person administering vaccine should draw up no more than one multidose vial, or 10 doses, at one time.
• Monitor patient flow to avoid drawing up unnecessary doses.
• Discard any remaining vaccine in predrawn syringes at the end of the workday.
• If different vaccines (such as flu and pneumococcal vaccines) will be available, set up a separate administration station for each vaccine type to prevent medication errors.

Additional information on vaccine storage and handling can be found below.

Influenza vaccine schedule for children

Annual influenza vaccination is recommended for people 6 months of age and older. Some children will need 2 doses of influenza vaccine during the same season. The following children will require 2 doses of influenza vaccine, administered at least 4 weeks apart:

• Children 6 months through 8 years of age who have never received seasonal influenza vaccine or for whom influenza vaccination history is unknown
• Children 6 months through 8 years of age who have not previously received at least 2 dosesA of seasonal influenza vaccine administered at least 4 weeks apart

The following children will require 1 dose of influenza vaccine:

• Children 6 months through 8 years of age who have previously received at least 2 dosesA of seasonal influenza vaccine administered at least 4 weeks apart
• Children 9 years of age and older

The two previous doses do not need to have been received during the same or consecutive influenza seasons.

Correct dosage (volume)

The amount of inactivated or recombinant (injectable) vaccine that should be administered intramuscularly is based on the patient's age and the vaccine product you are using.

• For children 6–35 months of age, the correct dosage (volume) is:
  • 0.25 mL for Afluria
  • 0.5 mL for Fluarix
  • 0.25 mL or 0.5 mL for Fluzone
  • 0.5 mL for FluLaval
  • 0.5 mL for Flucelvax
• For people 3 years of age and older, the correct dosage is 0.5 mL for inactivated or recombinant influenza vaccines. However, it is important to note that not all injectable vaccines are approved for all age groups.
  • Afluria, Fluarix, Flucelvax, FluLaval, and Fluzone are approved for people 6 months old and older,
  • Flublok is approved for people 9 years old and older,
  • Fluzone High-Dose and Fluad are approved for people 65 years old and older

The live attenuated influenza vaccine (nasal spray flu vaccine), FluMist, is packaged in a single-dose prefilled sprayer that contains 0.2 mL. The dose is divided between the two nostrils (0.1 mL is given in each nostril). FluMist is approved for people ages 2-49 years.

Route, site and needle length recommendations

Decisions on needle size and injection site when administering vaccine by intramuscular injection must be made for each person based on size of the muscle, thickness of the fatty tissue at the injection site, and injection technique. For older children and adults, the deltoid muscle in the upper arm is the preferred site, although the vastus lateralis muscle in the anterolateral thigh may be used if the deltoid site cannot be used. Influenza vaccines are not highly viscous, so a fine-gauge (22- to 25-gauge) needle can be used. Specific information on sites and needle length can be found in the Advisory Committee for Immunization Practices (ACIP) General Best Practice Guidelines for Immunization.

CDC has vaccine administration resources for clinicians administering influenza vaccine, including a needle length and gauge chart and demonstration videos for intramuscular injection and intranasal administration.

Additional information on vaccine administration and safe injection practices can be found in the following resources:

You should not aspirate before injecting the vaccine

Because there are no large blood vessels in the recommended sites, aspiration (i.e., pulling back on the syringe plunger after needle insertion but before injection) is not necessary before injecting vaccines. The ACIP General Best Practice Guidelines for Immunization state that aspiration is not required before administering a vaccine.

Coadministration

Inactivated influenza vaccine

You can give inactivated or recombinant (Flublok) influenza vaccine (flu shots) at the same time as other vaccines if other vaccines are indicated. When giving several injections during a single visit, administer each vaccine at a separate injection site. The injection sites should be separated by 1 inch or more, if possible, so that any local reactions can be differentiated.

Some flu vaccines containing nonaluminum adjuvants have become available, including an adjuvanted inactivated influenza vaccine (aIIV3, Fluad). Because there are limited data on simultaneous administration of two or more vaccines containing nonaluminum adjuvants and because nonadjuvanted influenza vaccines are available, selection of a nonadjuvanted influenza vaccine can be considered in situations in which influenza vaccine and another vaccine containing a nonaluminum adjuvant are to be administered concomitantly. However, influenza vaccination should not be delayed if a specific vaccine is not available.

Live attenuated influenza vaccine (nasal spray flu vaccine)

Live attenuated influenza vaccine (nasal spray flu vaccine) can be administered simultaneously with other live or non-live vaccines. However, if two live attenuated vaccines (injectable or intranasal) are not given during the same clinical visit, they should be separated by at least 4 weeks (28 days) to minimize the potential risk for interference. For example, if live attenuated influenza vaccine was given, at least 4 weeks should pass before MMR is administered.

Recommendations for people with egg allergies

Read the Advisory Committee on Immunization Practices recommendations for administering influenza vaccine to people with egg allergies.

Vaccine administration errors

A discussion of strategies to prevent errors can be found in the "Vaccine Administration" chapter of Epidemiology and Prevention of Vaccine-Preventable Diseases (the "Pink Book").

Inactivated influenza vaccine approved for adult use is inadvertently administered to a child

If an inactivated influenza formulation approved for adults is inadvertently administered to a child, this should be counted as a single valid dose for the child. However, this is considered a vaccine administration error. Healthcare personnel should take steps to determine how the error occurred and put strategies in place to prevent it from happening in the future. In addition, CDC encourages providers to report vaccine administration errors—even those where no adverse event occurred—to the Vaccine Adverse Event Reporting System (VAERS).

Injectable influenza vaccine administered by an incorrect route

If a formulation labeled for intramuscular injection is given by the subcutaneous or intradermal route, it should be repeated. The dose may be administered as soon as possible. There is no minimum interval required between the invalid dose (by subcutaneous or intradermal route) and the repeat dose.

Administering vaccine by the wrong route is considered a vaccine administration error. Healthcare personnel should take steps to determine how the error occurred and put strategies in place to prevent it from happening in the future.

In addition, CDC encourages providers to report vaccine administration errors—even those where no adverse event occurred—to the Vaccine Adverse Event Reporting System (VAERS).

Inadvertent administration of the wrong dosage (amount) of influenza vaccine

If a smaller than recommended dose (volume) of any inactivated influenza product is inadvertently administered, additional vaccine should be given so that the patient receives a full dose. The amount of vaccine that should be administered is based on when the patient is available to be revaccinated. For example:

• If a partial dose of an inactivated influenza vaccine product is administered and the error is recognized before the patient has left the clinic, the patient should receive a remaining volume to total the correct dosage. For example, if the correct dosage for the patient is 0.5 mL and they received only 0.25 mL, an additional 0.25 mL should be given (for a total of 0.5 mL) if revaccination can occur on the same day.
• If the patient has already left the clinic, a full dose of inactivated influenza vaccine should be administered as soon as the patient can return.
• If a larger dose (volume) of influenza vaccine is inadvertently administered, count the dose as valid. Revaccination with additional vaccine is not needed.

Giving an incorrect dose is considered a vaccine administration error. Healthcare personnel should take steps to determine how the error occurred and put strategies in place to prevent it from happening in the future.

In addition, CDC encourages providers to report vaccine administration errors—even those where no adverse event occurred— to the Vaccine Adverse Event Reporting System (VAERS).