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October 8, 2009

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NIAID Trial Testing 2009 H1N1 Flu Vaccine Plus Adjuvant

The National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health, has begun a clinical trial in healthy adults, including elderly individuals, testing a candidate 2009 H1N1 influenza vaccine combined with an adjuvant. An adjuvant is a substance added to a vaccine to boost the immune response to the vaccine.

Early results from ongoing clinical trials conducted independently by NIAID and by vaccine manufacturers indicate that one 15-microgram dose of 2009 H1N1 influenza vaccine without adjuvant likely will be enough to protect most healthy adults and older children from the virus. Thus, the United States does not plan to use adjuvants in a national vaccination program against 2009 H1N1 influenza. Trials of adjuvanted vaccines are being conducted, however, as a contingency plan in case they are needed in the future against the 2009 H1N1 influenza virus or against other influenza viruses with pandemic potential. An adjuvanted product might be needed, for example, if the virus mutates so that the unadjuvanted vaccine does not provide adequate protection; if certain populations do not mount an adequate immune response to vaccination; or if more doses of vaccine are required to protect the public.

The trial is being conducted through the NIAID-funded national network of Vaccine and Treatment Evaluation Units (VTEUs). Seven sites will enroll volunteers into the trial, including five VTEUs:  Seattle Group Health Research Institute, the lead site; the Emory University; the University of Iowa; the Cincinnati Children’s Hospital Medical Center; and the University of Maryland. These VTEU sites are joined by Stanford University School of Medicine and the University of Washington.

The trial will enroll up to 750 healthy adults: about 500 participants 18 to 64 years old, and 250 participants 65 years or older.

Participants will be divided into five equal groups based on the amount of vaccine they receive and whether or not it is paired with the adjuvant. The five groups are 3.75, 7.5 or 15 micrograms of vaccine plus adjuvant; and 7.5 or 15 micrograms vaccine without adjuvant. Each volunteer will be given an initial vaccine dose and a second dose of the same vaccine dosage 21 days later. Neither the trial participants nor the study researchers will know who receives which vaccine preparation.

Safety data will be collected and closely monitored throughout the trial by the study investigators and by an independent safety monitoring committee. Study investigators will take blood samples to determine the levels of antibodies stimulated by the vaccine at set time points before and after each injection.

The vaccine being tested in the trial is made by Sanofi Pasteur. Because the vaccine contains inactivated virus, it is impossible to become infected with the 2009 H1N1 influenza virus by receiving this vaccine. The adjuvant, AS03, is made by GlaxoSmithKline (GSK). GSK has reported testing AS03 adjuvant in clinical trials involving more than 39,000 people. GSK’s pre-pandemic and pandemic avian flu vaccines, both of which contain AS03, have received regulatory approvals in both the European Union and some Asian countries.

Detailed information about this trial of adjuvanted 2009 H1N1 influenza vaccine can be found on the ClinicalTrials.govWeb site at NCT00963157.

NIAID is planning to conduct at least one additional trial of a different candidate 2009 H1N1 influenza vaccine combined with the same AS03 adjuvant.

For more information about NIAID-sponsored clinical trials of 2009 H1N1 vaccine plus adjuvant, see Questions and Answers: Trial of a 2009 H1N1 Influenza Vaccine Plus Adjuvant.

For further information about NIAID-sponsored clinical trials of 2009 H1N1 influenza vaccines, see the following NIAID documents: Overview; Pediatric Trials; and Trials in Pregnant Women.

Visit for one-stop access to U.S. government information on avian and pandemic influenza. Also, visit NIAID’s flu web page.

Media inquiries can be directed to the NIAID Office of Communications at 301-402-1663,

NIAID conducts and supports research—at NIH, throughout the United States, and worldwide—to study the causes of infectious and immune-mediated diseases, and to develop better means of preventing, diagnosing and treating these illnesses. News releases, fact sheets and other NIAID-related materials are available on the NIAID Web site at

About the National Institutes of Health (NIH): NIH, the nation's medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit

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Last Updated October 08, 2009