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Content on this page was developed during the 2009-2010 H1N1 pandemic and has not been updated.

  • The H1N1 virus that caused that pandemic is now a regular human flu virus and continues to circulate seasonally worldwide.
  • The English language content on this website is being archived for historic and reference purposes only.
  • For current, updated information on seasonal flu, including information about H1N1, see the CDC Seasonal Flu website.

Updated Guidance for the Use of CSL™ 2009 H1N1 Monovalent Vaccine

December 29, 2009, 12:15 PM EDT


On November 11, 2009, the FDA expanded the approved use of CSL’s™ seasonal and 2009 H1N1 monovalent influenza vaccines to include children aged 6 months and older. Both vaccines had previously been approved only for use in adults, aged 18 years and older. The immediate effect on the national 2009 H1N1 monovalent flu vaccination program is that CSL’s™ 0.5 mL pre-filled syringe and 5 mL multi-dose vial formulations can now be used in a substantially broader range of ages. Currently, CSL™ 0.25 mL pre-filled syringes of 2009 H1N1 monovalent influenza vaccine are not available for use in the United States. CDC is making a programmatic recommendation and issuing clarifying guidance on use of CSL™ 2009 H1N1 monovalent vaccine that takes into account practical logistical considerations of allocation, ordering, and distribution of vaccine and ancillary supply kits.

Recommendation for use of 5 mL Multi-dose Vial Formulation

The CSL™ 2009 H1N1 5 mL multi-dose vial vaccine formulation is recommended for use in persons 6 months and older.

The quantities of ancillary supplies (needles, syringes, vaccination records, and alcohol prep pads) provided with each order of multi-dose vial vaccine are sufficient to administer 10 doses per vial.

Providers who choose to administer 0.25 mL doses from the multi-dose vial formulation to children aged 6-35 months, might need to supply their own needles, syringes, alcohol prep pads, and to print out additional vaccination records from the CDC website.

Providers should have adequate quantities of ancillary supplies if they choose to administer 0.5 mL doses from the multi-dose vial formulation to persons ages 3 years and older.

Recommendation for use of 0.5 mL Pre-filled Syringe Formulation

In order to prevent wasting vaccine, the CSL™ 2009 H1N1 0.5 mL pre-filled syringe vaccine formulation is recommended for use in children ages 6 through 35 months ONLY when other age appropriate formulations are not available. Providers should administer a half dose (0.25 mL) from the syringe and discard any unused vaccine. Unused doses should not be reserved to administer to the same patient at a later time, or to another individual. Transfer of vaccine content from one syringe to another also is not permissible.

The CSL™ 2009 H1N1 0.5 mL pre-filled syringe vaccine formulation is recommended for use in persons ages 3 years and older. There are no concerns with wasted vaccines and ancillary supplies provided with each order of vaccine will be sufficient.


If you have any questions or need clarification on this guidance please Email the CDC Immunization Desk.

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