ACIP Issues Recommendation for Use of CSL Influenza Vaccine

On Aug. 5, 2010, CDC's Advisory Committee on Immunization Practices (ACIP) met to discuss recommendations for use in the United States of seasonal influenza trivalent inactivated vaccine (TIV) [Afluria] manufactured by CSL Limited during 2010-11.

During the 2010 influenza season in Australia, administration of seasonal influenza TIV manufactured for the Southern Hemisphere by CSL Biotherapies (brand names Fluvax Junior and Fluvax) was associated with increased frequency of fever and febrile seizures in children aged 6 months through 4 years old. The rate of febrile seizures following Fluvax or Fluvax Jr was estimated at approximately 1 per 100 doses administered among children aged 6 months through 4 years old. There have also been increased reports of fever in children aged 5 years through 8 years following vaccination with 2010 Fluvax compared to the three previous seasons. On April 23, 2010, seasonal influenza vaccination of otherwise healthy children aged 5 years and younger was suspended in Australia by the chief medical officer. Similarly, following reports of febrile seizures, the New Zealand Ministry of Health recommended against the use of CSL Fluvax for children less than 5 years old.

While data are limited, no increase in febrile seizures has been reported to date with administration of other TIV products during the 2010 influenza season in the Southern Hemisphere. On July 30, 2010, vaccination of children less than 5 years was allowed to resume in Australia using TIV products other than Fluvax or Fluvax Junior. Despite extensive investigations, no cause has been identified to explain the increase in fevers and febrile seizures reported. The manufacturing process for Afluria is the same as for Fluvax and Fluvax Jr, and the composition of 2010 Fluvax and Fluvax Jr is antigenically equivalent to that for 2010-2011 Afluria.

In several studies conducted in influenza seasons prior to 2010-11 in the United States, no association between influenza vaccination with any brand of influenza vaccine and febrile seizures has been detected. Seasonal CSL TIV, marketed in the United States under the brand name Afluria, is approved by the Food and Drug Administration (FDA) for use in persons aged 6 months and older in the United States. Afluria was approved for use in adults 18 years and older in 2007, and subsequently, approved for use in children age 6 months and older in November 2009. Thus Afluria has not been widely used for pediatric vaccination of U.S. children. However, a clinical trial conducted in the U.S. of 2009 Northern Hemisphere TIV reported a higher frequency of fever following Afluria among children aged 6 months through 8 years old compared to a different TIV. On July 30, 2010, a warning was added to the Afluria package insert to inform U.S. healthcare practitioners that administration of CSL's 2010 Southern Hemisphere seasonal influenza vaccine has been associated with an increased number of reports relative to previous years of fever and febrile seizures following influenza vaccination in children predominantly below the age of 5 years.

ACIP Recommendation

Based upon the data to date suggesting an increased risk of febrile seizures in children aged 6 months through 4 years following 2010 Fluvax or Fluvax Jr, and a higher frequency of reported fever in children aged 5 years through 8 years following Fluvax compared to previous seasons; and based on a higher frequency of fever in children aged 5 years through 8 years following Afluria in one clinical trial in 2009, ACIP recommends that for the 2010-11 influenza season in the United States:

- Afluria should not be used in children aged 6 months through 8 years.

- Other age-appropriate, licensed seasonal influenza vaccine formulations should be used for prevention of influenza in children aged 6 months through 8 years.

- If no other age-appropriate, licensed seasonal influenza vaccine is available for a child aged 5 years through 8 years old who has a medical condition that increases their risk for influenza complications, Afluria may be given, and providers should discuss the benefits and risks of influenza vaccination with the parents or caregivers before administering Afluria.

There are two types of seasonal influenza vaccines for children: the trivalent inactivated vaccine (TIV) (the flu shot) and the live attenuated vaccine (nasal spray)

*If no other age-appropriate, licensed inactivated seasonal influenza vaccine is available for a child aged 5 years through 8 years old who has a medical condition that increases their risk for influenza complications; providers may use Afluria. However, providers should discuss the benefits and risks of influenza vaccination with the parents or caregivers before administering Afluria.

For a detailed table from the CDC, visit http://www.cdc.gov/flu/protect/vaccine/vaccines.htm