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Failure of protection and enhanced pneumonia with a US H1N2 swine influenza virus in pigs vaccinated with an inactivated classical swine H1N1 vaccine

Emily

Emily

Editor, Senior Moderator
http://www.ars.usda.gov/research/publications/publications.htm?seq_no_115=204405
Research Project: EMERGING VIRAL DISEASES OF SWINE

Location: Virus and Prion Diseases of Livestock

Title: Failure of protection and enhanced pneumonia with a US H1N2 swine influenza virus in pigs vaccinated with an inactivated classical swine H1N1 vaccine

Authors
item Vincent, Amy
item Lager, Kelly
item Janke, Bruch - IOWA STATE UNIVERSITY
item Gramer, Marie - UNIVERSITY OF MINNESOTA
item Richt, Juergen

Submitted to: Veterinary Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 10, 2007
Publication Date: January 25, 2008
Citation: Vincent, A.L., Lager, K.M., Janke, B.H., Gramer, M.R., Richt, J.R. 2008. Failure of protection and enhanced pneumonia with a US H1N2 swine influenza virus in pigs vaccinated with an inactivated classical swine H1N1 vaccine. Veterinary Microbiology. 126(4):

Interpretive Summary: This study evaluated influenza vaccines in pigs. Vaccines included inactivated (killed) and live virus exposure with two different isolates of swine influenza virus (SIV) of the H1 subtype. The killed vaccines provided complete protection against challenge with live virus that was the same as that contained in the vaccine. However, one of the killed vaccines did not protect against live virus challenge with the different SIV isolate. All of the pigs in this group were shown microscopically to have virus distributed throughout the lung in contrast to control pigs. In addition, pneumonia caused by the influenza virus was dramatically worse in one-third of the pigs receiving the mismatched vaccine. In contrast, live virus exposure followed by challenge with the different influenza virus was completely protective. This study suggests that immunity to influenza virus is complex and there may be a risk of enhancing disease when the inactivated vaccine virus is mismatched with the challenge virus.

Technical Abstract: We evaluated two US swine influenza virus (SIV) isolates, A/Swine/Iowa/15/1930 H1N1 (IA30) and A/Swine/Minnesota/00194/2003 H1N2 (MN03), with substantial genetic variation in the HA gene and failure to cross-react in the hemagglutination inhibition (HI) assay, in an in vivo vaccination and challenge model. Inactivated vaccines were prepared from each isolate and used to immunize conventional pigs, followed by challenge with homologous or heterologous virus. Both inactivated vaccines provided complete protection against homologous challenge and the MN03 vaccine provided partial protection against IA30. However, the IA30 vaccine failed to protect against the heterologous MN03 challenge. Three of the nine pigs in this group had substantially greater percentages of lung lesions, suggesting the IA30 inactivated vaccine potentiated the pneumonia caused by the MN03 challenge. In contrast, priming with live IA30 virus provided protection from nasal shedding and virus replication in the lung in MN03 challenged pigs. These data indicate that divergent H1 viruses that do not cross-react serologically may not provide complete cross-protection when used in inactivated vaccines against heterologous challenge. In addition, live virus infection can confer protection against heterologous challenge.
 
Re: Failure of protection and enhanced pneumonia with a US H1N2 swine influenza virus in pigs vaccinated with an inactivated classical swine H1N1 vaccine

above paper:

Authors

Vincent, Amy
Lager, Kelly
Janke, Bruch - IOWA STATE UNIVERSITY
Gramer, Marie - UNIVERSITY OF MINNESOTA
Richt, Juergen


Submitted to: Veterinary Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 10, 2007
Publication Date: January 25, 2008
Citation: Vincent, A.L., Lager, K.M., Janke, B.H., Gramer, M.R., Richt, J.R. 2008. Failure of protection and enhanced pneumonia with a US H1N2 swine influenza virus in pigs vaccinated with an inactivated classical swine H1N1 vaccine. Veterinary Microbiology. 126(4):310-323.

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Just to clarify that the H1N1 in this article is NOT the current novel H1N1.

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Re: Failure of protection and enhanced pneumonia with a US H1N2 swine influenza virus in pigs vaccinated with an inactivated classical swine H1N1 vaccine

This study suggests that immunity to influenza virus is complex and there may be a risk of enhancing disease when the inactivated vaccine virus is mismatched with the challenge virus.
Click to expand...

Why would that happen?

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Re: Failure of protection and enhanced pneumonia with a US H1N2 swine influenza virus in pigs vaccinated with an inactivated classical swine H1N1 vaccine

"enhancing disease" could be enhanced over vaccination with a matching
strain or enhanced over no vaccination/exposure at all.
(original antigenic sin)


did they vaccinate the pigs with live, attenuated virus
or did they really infect the pigs with flu from 1930 and 2003 ?
 
Re: Failure of protection and enhanced pneumonia with a US H1N2 swine influenza virus in pigs vaccinated with an inactivated classical swine H1N1 vaccine

....pneumonia caused by the influenza virus was dramatically worse in one-third of the pigs receiving the mismatched vaccine
Click to expand...

Can the same thing happen in humans? If so, the implications are enormous.

When they say mismatched, how mismatched must it be to create this problem?

Would humans getting a vaccination of old seasonal H1N1 have the above impact should they get the novel 2009 H1N1?

Which human vaccine is the killed version?

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Re: Failure of protection and enhanced pneumonia with a US H1N2 swine influenza virus in pigs vaccinated with an inactivated classical swine H1N1 vaccine

This article describes several flu vaccination "train wrecks" in pigs, but no details on how mismatched the strains were:

http://www.newscientist.com/article/dn17077-flu-outbreak-the-pig-connection.html

With classical H1N1, H3N2, H1N2 and rH1N1 in pigs, hopefully they are more prone to mismatch problems than humans would be. I remember reading that the government was deciding at one point between giving the pandemic flu vaccine together in one shot with the seasonal flu vaccine. You would hope they would have been aware of any dangers when they opted to give the seasonal and new pandemic vaccines separately.

ETA:

Canada -

http://www.flutrackers.com/forum/showthread.php?t=126261
http://www.cbc.ca/health/story/2009/09/23/h1n1-flu-shots.html?ref=rss
"All options on table in Quebec

Epidemiological studies are also underway to test whether one vaccine cancels out the efficacy of the other and to tease out which one may cause side-effects if both shots are given around the same time.

In previous pandemics, the new influenza A virus replaced seasonal influenza A viruses, but it's too early to tell if this will also occur now.

White said Quebec is considering all options, namely:

Giving seasonal vaccine as usual.
Delaying seasonal flu shots until after the pandemic vaccine is delivered.
Scaling back the seasonal flu campaign to focus on those at highest risk of those strains, such as seniors.
Cancelling seasonal flu shots. "
 
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Re: Failure of protection and enhanced pneumonia with a US H1N2 swine influenza virus in pigs vaccinated with an inactivated classical swine H1N1 vaccine

Another matter is species-specific responses, e.g., poultry are regularly vaccinated with a slightly different strain intentionally - to differentiate between infections and vaccinations. For instance, to fight H5N1, they might vaccinate with H5N2 - and it works for poultry. Poultry have slightly different responses to vaccines.

Do we know if swine respond exactly like humans?

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Re: Failure of protection and enhanced pneumonia with a US H1N2 swine influenza virus in pigs vaccinated with an inactivated classical swine H1N1 vaccine

From post #6:
In previous pandemics, the new influenza A virus replaced seasonal influenza A viruses, but it's too early to tell if this will also occur now.
Click to expand...

The 1977 reappearance of H1N1 after a 20-year absence, did not replace H3N2.
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...a twenty-year disappearance and sudden reappearance in 1977, and cycles of alternating dominance with the H3N2 influenza A virus subtype ever since.
Click to expand...
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=2262849

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