Safety and Immunogenicity of Nonadjuvanted and MF59-Adjuvanted Influenza A/H9N2 Vacci

[Snowy Owl]

Safety and Immunogenicity of Nonadjuvanted and MF59-Adjuvanted Influenza A/H9N2 Vaccine Preparations
http://www.journals.uchicago.edu/ucp/WebIntegrationServlet?call=ContentWeblet&url=http://www.journals.uchicago.edu/CID/journal/issues/v43n9/39957/39957.html&current_page=content

<author><fname>Robert L. </fname><surname>Atmar</surname></author>, <author><fname>Wendy A. </fname><surname>Keitel</surname></author>, <author><fname>****al M. </fname><surname>Patel</surname></author>, <author><fname>Jacqueline M. </fname><surname>Katz</surname></author>, <author><fname>Dewei </fname><surname>She</surname></author>, <author><fname>Hana El </fname><surname>Sahly</surname></author>, <author><fname>Justine </fname><surname>Pompey</surname></author>, <author><fname>Thomas R. </fname><surname>Cate</surname></author>, and <author><fname>Robert B. </fname><surname>Couch

</surname></author>

Volume 43(2006), pages 000 - 000
DOI: 10.1086/508174
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Abstract Background. Influenza A/H9N2 viruses can infect humans and are considered to be a pandemic threat. Effective vaccines are needed for these and other avian influenza viruses.
Methods. We performed a phase I, randomized, double-blind trial to evaluate the safety and immunogenicity of a 2-dose schedule (administered on days 0 and 28) of 4 dose levels (3.75, 7.5, 15, and 30

g of hemagglutinin) of inactivated influenza A/chicken/Hong Kong/G9/97 (H9N2) vaccine with and without MF59 adjuvant. Vaccine safety was assessed with a diary and selected blood tests. Immunogenicity was measured using serum hemagglutination inhibition (HAI) and microneutralization (MNt) antibody assays.
Results. Ninety-six healthy adults (age, 18

34 years) were enrolled in the study. Arm discomfort was more common in groups that received adjuvant, but adverse effects of the vaccination were generally mild. Geometric mean serum HAI and MNt antibody titers to the influenza A/chicken/Hong Kong/G9/97 (H9N2) virus strain for all vaccine groups were similar on day 0 but were significantly higher (<formula><f>P<.001</f></formula>) on both days 28 and 56 for the MF59-adjuvanted vaccine groups than for groups given nonadjuvanted vaccine. Other measures of immunogenicity were also higher in the adjuvanted vaccine groups. HAI and MNt geometric mean titers measured after the administration of a single dose of MF59-adjuvanted vaccine were similar to those measured after 2 doses of nonadjuvanted vaccine.
Conclusions. The combination of MF59 adjuvant with a subunit vaccine was associated with improved immune responses to an influenza A/H9N2 virus. The adjuvanted vaccine was immunogenic even after a single dose, raising the possibility that a 1-dose vaccination strategy may be attainable with the use of adjuvanted vaccine.

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[Snowy Owl]

Re: Safety and Immunogenicity of Nonadjuvanted and MF59-Adjuvanted Influenza A/H9N2 Vacci

<TR><TD class=am_048artTitle>Bird Flu Vaccine Additive May Stretch Supply</TD></TR>
http://www.infectioncontroltoday.com/hotnews/69h25804374751.html
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<TR><TD class=am_048artPostDate>Posted on: 09/25/2006</TD></TR>
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Researchers have achieved an effective immune response to an avian influenza vaccine with doses as low as one-quarter of the norm when they added a chemical mixture known as MF59. The research is published in the November 1 issue of Clinical Infectious Diseases, now available online.

MF 59 is an adjuvant?a substance that increases the immune system's ability to respond to a stimulus. For this research, the investigators used inactivated H9N2 influenza vaccines?not the H5N1 virus currently feared as a potential pandemic strain. However, the study does suggest that if the feared pandemic comes to be, adjuvants might be used to extend the vaccine supply. Furthermore, the authors note, H9N2 is itself a pandemic threat.

The researchers vaccinated 96 young adults who were divided into eight groups receiving different dosage levels, half of the groups with and half without the MF59 adjuvant. The volunteers were tested for antibodies at 28 days and 56 days.

"Antibody in the blood to the influenza virus that you're trying to protect against is what protects people from getting the flu," said Robert Atmar, MD, lead author of the study. "What vaccines do is cause the vaccinated person to produce antibodies in their bloodstream. The higher the antibody levels, in general, the more likely people are to be protected from getting ill or from getting infected at all.

"What we found was that when the adjuvant material was included in the vaccine?at all dosage levels?the antibody response was significantly better, and as low as one-quarter the dose worked very well. And a single dose of the adjuvanted vaccine was as good as two doses of the vaccine without the adjuvant." This suggests that adjuvants might be used to stretch a limited vaccine supply and allow vaccination of greater numbers of people.

Neither group experienced serious reactions to the vaccines. However, mild pain or swelling was more common in the adjuvant group.

Source: Infectious Disease Society of America (IDSA)



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