Regular flu vaccine may help against H5N1 -study

[AlaskaDenise]

• <LI class=publication>Reuters
• Wednesday December 26 2007

WASHINGTON, Dec 26 (Reuters) - Ordinary seasonal flu vaccines may provide a small amount of protection against bird flu, Italian researchers reported on Wednesday.

Their study is among the first to support the idea that getting an annual flu shot may help people's bodies fight off the H5N1 virus, which has killed 210 people in 13 countries and infected 341.

Cristiana Gioia, Maria Capobianchi and colleagues at the National Institute for Infectious Diseases Lazzaro Spallanzani in Rome tested the blood of 42 volunteers who had been vaccinated against seasonal influenza.

In the laboratory, they added H5N1 virus to the blood and found that in some of the volunteers immune system proteins called antibodies acted against the bird flu virus.

They also found a few immune cells called CD4 T-cells seemed to recognize and act against H5N1 virus "and seasonal vaccine administration enhanced the frequency of such reactive CD4 T-cells," they wrote in the journal Emerging Infectious Diseases.

"Our findings indicate that vaccination can raise neutralizing immunity against (H5N1 avian influenza) seasonal virus," the researchers concluded. This could help explain why H5N1, which only rarely affects people, is even rarer among the elderly, Gioia's team wrote.

"This finding may be explained by hypothesizing that older people, although not previously exposed to H5N1 subtype, may have gained protective immunity by previous infections sustained by circulating influenza virus strains," they wrote.

Several types of influenza circulate globally among people at any given time and these strains constantly mutate. This means flu vaccines have to be reformulated every year to match the mutations.

Health experts around the world are trying to boost rates of annual flu vaccination for two reasons -- because flu itself kills between 250,000 and 500,000 people a year, and also to help the world prepare for a pandemic.

These experts agree a pandemic is overdue, and fear H5N1 could cause the next one as it is constantly popping up among birds and a few people in Asia and Africa and among birds in Europe.

If more people get vaccinated against seasonal flu, companies will make more of the vaccine and can quickly turn production to match whatever strain of pandemic flu, including some version of H5N1, that may eventually occur.

(Reporting by Maggie Fox; editing by Stuart Grudgings)

http://www.guardian.co.uk/feedarticle?id=7179497

[Giuseppe]

Re: Regular flu vaccine may help against H5N1 -study

On the same argument:
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1.4): J Virol. 2007 Nov 21; [Epub ahead of print]
Induction of Heterosubtypic Immunity to Influenza Virus by Intranasal Immunization.

Quan FS, Compans RW, Nguyen HH, Kang SM.
Department of Microbiology and Immunology and Emory Vaccine Center, Emory University School of Medicine, Atlanta, Georgia, USA., Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, USA, and International Vaccine Institute, Seoul, Korea.

Recovery from live influenza virus infection is known to induce heterosubtypic immunity.

In contrast, immunity induced by inactivated vaccines is predominantly subtype specific.

In this study, we investigated the heterosubtypic protective immunity induced by inactivated influenza virus.

Intranasal immunization of mice with inactivated influenza virus A/PR8 (H1N1) provided complete protection against the homologous virus and a drift virus within the same subtype, A/WSN (H1N1), but not against the heterosubtypic virus, A/Philippines (H3N2).

However, co-administration of inactivated virus with cholera toxin (CT) as adjuvant conferred complete heterosubtypic protection, without observed illness, even under conditions of CD4(+) or CD8(+) T cell-depletion.

Analysis of immune correlates prior to challenge and post-challenge infection indicated that humoral immune responses with cross-neutralizing activity in lungs and in sera play a major role in conferring protective immunity against heterosubtypic challenge.

This study has significant implications for developing broadly cross-reactive vaccines against newly emerging pathogenic influenza viruses.

PMID: 18032492 [PubMed - as supplied by publisher]

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http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=Retrieve&db=PubMed&dispmax=8&list_uids=18030546,18024888,18032512,18032492,18029826,18029825,18029064,18022736&dopt=AbstractPlus

[Giuseppe]

Re: Regular flu vaccine may help against H5N1 -study

More specific:
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1.3): J Infect Dis. 2007 Nov 1;196(9):1313-20. Epub 2007 Oct 5.
Cross-Protection against H5N1 Influenza Virus Infection Is Afforded by Intranasal Inoculation with Seasonal Trivalent Inactivated Influenza Vaccine.

Ichinohe T, Tamura S, Kawaguchi A, Ninomiya A, Imai M, Itamura S, Odagiri T, Tashiro M, Takahashi H, Sawa H, Mitchell WM, Strayer DR, Carter WA, Chiba J, Kurata T, Sata T, Hasegawa H.
Department of Pathology, National Institute of Infectious Diseases, Musashimurayama-shi, Tokyo, 208-0011, Japan. hasegawa@nih.go.jp.


Background.

Avian H5N1 influenza A virus is an emerging pathogen with the potential to cause substantial human morbidity and mortality.

We evaluated the ability of currently licensed seasonal influenza vaccine to confer cross-protection against highly pathogenic H5N1 influenza virus in mice.


Methods.

BALB/c mice were inoculated 3 times, either intranasally or subcutaneously, with the trivalent inactivated influenza vaccine licensed in Japan for the 2005-2006 season.

The vaccine included A/NewCaledonia/20/99 (H1N1), A/NewYork/55/2004 (H3N2), and B/Shanghai/361/2002 viral strains and was administered together with poly(I):poly(C(12)U) (Ampligen) as an adjuvant.

At 14 days after the final inoculation, the inoculated mice were challenged with either the A/HongKong/483/97, the A/Vietnam/1194/04, or the A/Indonesia/6/05 strain of H5N1 influenza virus.


Results.

Compared with noninoculated mice, those inoculated intranasally manifested cross-reactivity of mucosal IgA and serum IgG with H5N1 virus, as well as both a reduced H5N1 virus titer in nasal-wash samples and increased survival, after challenge with H5N1 virus.

Subcutaneous inoculation did not induce a cross-reactive IgA response and did not afford protection against H5N1 viral infection.


Conclusions.

Intranasal inoculation with annual influenza vaccine plus the Toll-like receptor-3 agonist, poly(I):poly(C(12)U), may overcome the problem of a limited supply of H5N1 virus vaccine by providing cross-protective mucosal immunity against H5N1 viruses with pandemic potential.

PMID: 17922395 [PubMed - in process]

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http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=Retrieve&db=PubMed&dispmax=10&list_uids=17919743,17251395,17922395,17703412,17703411,17905166,17905148,17920168,17920165,17919786&dopt=AbstractPlus

[AlaskaDenise]

Re: Regular flu vaccine may help against H5N1 -study

This could help explain why H5N1, which only rarely affects people, is even rarer among the elderly, Gioia's team wrote.

"This finding may be explained by hypothesizing that older people, although not previously exposed to H5N1 subtype, may have gained protective immunity by previous infections sustained by circulating influenza virus strains," they wrote.

How can hypothesis be true if older people have a higher mortality rate from regular flu?

.

[AlaskaDenise]

Re: Regular flu vaccine may help against H5N1 -study

Iron:

Timing is a contributing factor.

Those HK ducks who were immune to H5N1 due to a recent H9N2 infection was claimed to be due to cross-reactive immunity. I'm not sure if they meant the recently active part of the innate system, or a heightened humoral system. However, I've long wondered if this is why the Russians always administer current flu vaccine to villagers when a poultry infection hits a village....they've had a remarkable lack of human infections, considering all the poultry infections they've had.

I cannot find the reference to that HK duck paper, but I remember it well.
The ducks had their H9N2 infection less than 30 days prior to H5N1 exposure. That window of protention lasts for about 100 days.

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[Giuseppe]

Re: Regular flu vaccine may help against H5N1 -study

Adults could have an extended 'archive' of immune cell memory that recognize a greater number of influenza variants than youngers.
Elderly people develops severe complications after influenza infections due in part of a minor potency of immune cell activation (eg: immune cells could recognize well the viruses but they require a quick activation, that may lack in some patient with underlying diseases and general poor health status).
In the blood of people born before 1918 was isolated antibodies against A/H1N1 with neutralizing capacity of 'spanish flu' virus HA.

[Giuseppe]

Re: Regular flu vaccine may help against H5N1 -study

Chinese researchers highlights recently as A/H9N2 virus reassorted with avian A/H5N1, creating a variant with internal genes of avian origin. Limited evidence exists to date that NS1 protein can exert a protective immune response. But it may be.
In Russia, it is not clear whether they are using a trivalent inactivated seasonal human vaccine or a pre-pandemic vaccine or a combination of both, or a trivalent cold-adapted live-attenuated human vaccine.

[AlaskaDenise]

Re: Regular flu vaccine may help against H5N1 -study

........In the blood of people born before 1918 was isolated antibodies against A/H1N1 with neutralizing capacity of 'spanish flu' virus HA.

I remember reading that those antibodies were an extremely high level (even 80 years later), but I've been unable to locate the reference to refresh my memory. Do you have a reference?

Why should those antibody levels be higher than other influenza antibody levels?

.

[Giuseppe]

Re: Regular flu vaccine may help against H5N1 -study

I have the original slide (A. Garcia-Sastre, Characterization of the 1918 influenza virus - Collaborative effort among different research groups and institutions - Jeffery K. Taubenberger, Adolfo Garc&#237;a-Sastre, Peter Palese, Christopher F. Basler, Terrence M. Tumpey, David E. Swayne, Michael G. Katze, A. Wilson - NIH/NIAID support: P01 AI0581113)
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Two shots:

[sharon sanders]

Re: Regular flu vaccine may help against H5N1 -study

La ringrazio Ironorehopper.

[AlaskaDenise]

Re: Regular flu vaccine may help against H5N1 -study

Thanks IronOreHopper.

I had thought one survivor tested at 1000 times a "normal" influenza antibody level........isn't it incredible?

Now if someone knows.......why?

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