Giuseppe
Emeritus
[Source: World Health Organization, Weekly Epidemiological Record (WER), full PDF document: (LINK). Extract.]
Weekly epidemiological record / Relev? ?pid?miologique hebdomadaire - 14 February 2014, 89th year / 14 F?VRIER 2014, 89e ann?e / No. 7, 2014, 89, 53?60 - http://www.who.int/wer
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Global Advisory Committee on Vaccine Safety, 11?12 December 2013
The Global Advisory Committee on Vaccine Safety (GACVS), an expert clinical and scientific advisory body, was established by WHO to provide independent, scientifically rigorous advice on vaccine safety issues of potential global importance.
GACVS held its 29th meeting in Geneva, Switzerland, on 11?12 December 2013. The committee reviewed the following topics: the safety profiles of chimeric Japanese encephalitis, inactivated poliovirus, and rotavirus vaccines; allegations related to the safety of human papillomavirus vaccine (HPV); investigations related to increased pyrogenicity of seasonal influenza vaccine; and the development of a global vaccine safety surveillance manual addressing basic concepts for immunization programme managers and regulatory staff.
(...)
Increased occurrence of febrile seizures with a seasonal influenza vaccine
GACVS reviewed progress by the Australian Therapeutic Goods Administration (TGA) and the company that manufactures Fluvax (CSL, Parkville, Victoria, Australia) a trivalent influenza vaccine (TIV) vaccine which, in 2010, was associated with an increased risk of fever and febrile seizures, particularly in children aged <5 years.(6)
This resulted in a 3-month suspension of the Australian influenza vaccination programme for children. Subsequent investigations confirmed that no other TIVs were associated with this increased risk. Fluvax is now contraindicated in children aged <5 years and avoided in those aged <9 years.
The manufacturer has conducted several analyses in order to clarify the etiological mechanism of increased pyrogenicity of this specific vaccine product. Initial findings identified several possible contributing factors that may have triggered the reaction to the vaccine. These factors include, in particular, the presence of large RNA fragments, as well as characteristics of the B Brisbane seed virus strain used in seasonal influenza vaccines in 2010 that has a greater ability to maintain RNA fragments during the manufacturing process. GACVS noted that the virus splitting process used by CSL differs from that used by other manufacturers. The company informed GACVS of a planned modification to the vaccine manufacturing process that will be implemented in 2014. It is expected that this modification will lead to a reduction or elimination of the possible contributing factors and therefore a reduction in the additional pyrogenicity.
GACVS recommended that further studies be undertaken in healthy adult (non-pregnant) subjects to ascertain the impact of the new manufacturing process, particularly on safety of the product. Once shown to be safe in this group, the safety of Fluvax in pregnant women will need to be assessed.
GACVS concurred with TGA?s decision to contraindicate the use of the present CSL vaccine in children aged <5 years. The committee also took note of measures mandated by TGA to reduce inadvertent vaccination, which have included a number of programmatic measures including package labelling.
GACVS noted these events illustrate the importance of post-licensure brand-specific safety surveillance which presents particular challenges with seasonal influenza vaccines.
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(6) See No. 29, 2013, pp. 301?312.
(?)
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Weekly epidemiological record / Relev? ?pid?miologique hebdomadaire - 14 February 2014, 89th year / 14 F?VRIER 2014, 89e ann?e / No. 7, 2014, 89, 53?60 - http://www.who.int/wer
___
Global Advisory Committee on Vaccine Safety, 11?12 December 2013
The Global Advisory Committee on Vaccine Safety (GACVS), an expert clinical and scientific advisory body, was established by WHO to provide independent, scientifically rigorous advice on vaccine safety issues of potential global importance.
GACVS held its 29th meeting in Geneva, Switzerland, on 11?12 December 2013. The committee reviewed the following topics: the safety profiles of chimeric Japanese encephalitis, inactivated poliovirus, and rotavirus vaccines; allegations related to the safety of human papillomavirus vaccine (HPV); investigations related to increased pyrogenicity of seasonal influenza vaccine; and the development of a global vaccine safety surveillance manual addressing basic concepts for immunization programme managers and regulatory staff.
(...)
Increased occurrence of febrile seizures with a seasonal influenza vaccine
GACVS reviewed progress by the Australian Therapeutic Goods Administration (TGA) and the company that manufactures Fluvax (CSL, Parkville, Victoria, Australia) a trivalent influenza vaccine (TIV) vaccine which, in 2010, was associated with an increased risk of fever and febrile seizures, particularly in children aged <5 years.(6)
This resulted in a 3-month suspension of the Australian influenza vaccination programme for children. Subsequent investigations confirmed that no other TIVs were associated with this increased risk. Fluvax is now contraindicated in children aged <5 years and avoided in those aged <9 years.
The manufacturer has conducted several analyses in order to clarify the etiological mechanism of increased pyrogenicity of this specific vaccine product. Initial findings identified several possible contributing factors that may have triggered the reaction to the vaccine. These factors include, in particular, the presence of large RNA fragments, as well as characteristics of the B Brisbane seed virus strain used in seasonal influenza vaccines in 2010 that has a greater ability to maintain RNA fragments during the manufacturing process. GACVS noted that the virus splitting process used by CSL differs from that used by other manufacturers. The company informed GACVS of a planned modification to the vaccine manufacturing process that will be implemented in 2014. It is expected that this modification will lead to a reduction or elimination of the possible contributing factors and therefore a reduction in the additional pyrogenicity.
GACVS recommended that further studies be undertaken in healthy adult (non-pregnant) subjects to ascertain the impact of the new manufacturing process, particularly on safety of the product. Once shown to be safe in this group, the safety of Fluvax in pregnant women will need to be assessed.
GACVS concurred with TGA?s decision to contraindicate the use of the present CSL vaccine in children aged <5 years. The committee also took note of measures mandated by TGA to reduce inadvertent vaccination, which have included a number of programmatic measures including package labelling.
GACVS noted these events illustrate the importance of post-licensure brand-specific safety surveillance which presents particular challenges with seasonal influenza vaccines.
_________
(6) See No. 29, 2013, pp. 301?312.
(?)
-
------