Medicago Inc MDCGF

Sorry guys...again

[EDDY05]

Received 3 February 2009/Accepted 7 May 2009

As part of influenza pandemic preparedness, policy decisionsneed to be made about how best to utilize vaccines once theyare manufactured. Since H5N1 avian influenza virus has the potentialto initiate the next human pandemic, isolates of this subtypehave been used for the production and testing of prepandemicvaccines. Clinical trials of such vaccines indicate that twoinjections of preparations containing adjuvant will be requiredto induce protective immunity. However, this is a working assumptionbased on classical serological measures only. Examined hereare the dose of viral hemagglutinin (HA) and the number of inoculationsrequired for two different H5N1 vaccines to achieve protectionin ferrets after lethal H5N1 challenge. Ferrets inoculated twicewith 30 µg of A/Vietnam/1194/2004 HA vaccine with AlPO4,or with doses as low as 3.8 µg of HA with Iscomatrix (ISCOMATRIX,referred to as Iscomatrix herein, is a registered trademarkof CSL Limited) adjuvant, were completely protected againstdeath and disease after H5N1 challenge, and the protection lastedat least 15 months. Cross-clade protection was also observedwith both vaccines. Significantly, complete protection againstdeath could be achieved with only a single inoculation of H5N1vaccine containing as little as 15 µg of HA with AlPO4or 3.8 µg of HA with Iscomatrix adjuvant. Ferrets vaccinatedwith the single-injection Iscomatrix vaccines showed fewer clinicalmanifestations of infection than those given AlPO4 vaccinesand remained highly active. Our data provide the first indicationthat in the event of a future influenza pandemic, effectivemass vaccination may be achievable with a low-dose "single-shot"vaccine and provide not only increased survival but also significantreduction in disease severity.

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* Corresponding author. Mailing address: Department of Microbiology andImmunology, The University of Melbourne, Parkville, Victoria 3010,Australia. Phone: [phone]. Fax: [phone]. E-mail: [e-mail]