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J Infect Dis. 2010 Apr 1;201(7):1000-6. doi: 10.1086/651171.

Assessment of the efficacy of commercially available and candidate vaccines against a pandemic H1N1 2009 virus.

Author information

1
Special Pathogens Program, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba R3E 3R2, Canada. gary_kobinger@phac-aspc.gc.ca

Abstract

BACKGROUND:

The emergence and global spread of the pandemic H1N1 2009 influenza virus have raised questions regarding the protective effect of available seasonal vaccines and the efficacy of a newly produced matched vaccine.

METHODS:

Ferrets were immunized with the 2008-2009 formulations of commercially available live attenuated (FluMist; MedImmune) or split-inactivated (Fluviral; GlaxoSmithKline) vaccines, a commercial swine vaccine (FluSure; Pfizer), or a laboratory-produced matched inactivated whole-virus vaccine (A/Mexico/InDRE4487/2009). Adaptive immune responses were monitored, and the animals were challenged with A/Mexico/InDRE4487/2009 after 5 weeks.

RESULTS:

Only animals that received the swine or matched vaccines developed detectable hemagglutination-inhibiting antibodies against the challenge virus, whereas a T cell response was exclusively detected in animals vaccinated with FluMist. After challenge, all animals had high levels of virus replication in the upper respiratory tract. However, preexisting anti-pandemic H1N1 2009 antibodies resulted in reduced clinical signs and improved survival. Surprisingly, FluMist was associated with a slight increase in mortality and greater lung damage, which correlated with early up-regulation of interleukin-10.

CONCLUSIONS:

The present study demonstrates that a single dose of matched inactivated vaccine confers partial protection against a pandemic H1N1 2009 virus, and it suggests that a higher dose or prime-boost regimen may be required. The consequences of mismatched immunity to influenza merit further investigation.

PMID:
20170374
DOI:
10.1086/651171
[Indexed for MEDLINE]

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