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August 19, 2009

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Pediatric Trials of 2009 H1N1 Influenza Vaccine at NIAID Vaccine and Treatment Evaluation Units (VTEUs)

1. When did the trials in children begin?

On Monday, August 17, 2009, the Safety Monitoring Committee reviewed initial safety data from more than 500 volunteers enrolled in the first three trials of 2009 H1N1 influenza vaccines in adult and elderly people. The Safety Monitoring Committee determined that the pediatric trials could begin. NIAID agreed with those recommendations and authorized the two trials of 2009 H1N1 influenza vaccine in children to begin the next day.

2. Who is on the Safety Monitoring Committee?

The Safety Monitoring Committee is a panel of outside experts convened by NIAID to evaluate the safety data from these and other VTEU 2009 H1N1 influenza vaccine trials. The individuals on this independent committee are recognized experts in the fields of pediatrics, infectious diseases and vaccine practice and safety. They review and comment on the scientific study before enrollment begins. Once the study starts, the committee meets regularly to review data and safety information related to the study and is also available for ad hoc meetings as needed.

3. How many trials are being conducted with children?

At this time, the VTEUs are conducting two pediatric clinical trials of 2009 H1N1 influenza vaccines. Researchers participating in these two trials are located at several medical centers across the country (listed below).

4. What are the objectives and the design of these studies?

The two trials are enrolling children between 6 months and 17 years of age. Each trial will look at specific scientific questions:

Dosing Trial:

The dosing trial is assessing how large a vaccine dose, and how many doses of vaccine, are needed to induce an immune response that is predictive of protection.

Children enrolled in the trial received 15 or 30 micrograms of vaccine on their first visit and a second dose of the same strength of vaccine three weeks later. The trial enrolled up to 650 children at five locations nationwide (listed below).

Combination Trial:

The combination trial is testing a 2009 H1N1 influenza vaccine given together with licensed inactivated seasonal flu vaccine. The goal is to determine if 15 micrograms of 2009 H1N1 influenza vaccine can be safely administered at the same time or sequentially with 45 micrograms of the seasonal flu vaccine (containing three components with 15 micrograms of each), and if both vaccines will induce immune responses predictive of protection from future infection.

To be eligible for the combination trial, children must have previously received two doses of seasonal flu vaccine in one year or be older than 9 years. The trial enrolled up to 650 children at six locations nationwide (listed below).

5. Where are the pediatric trials taking place?

In all, 11 medical centers are participating in the pediatric clinical trials of H1N1 influenza vaccine:

The dosing trial is taking place at five locations:

  • Baltimore (University of Maryland School of Medicine VTEU, the lead site for this trial)
  • Nashville (Vanderbilt University VTEU)
  • Durham, NC (Duke University)
  • Kansas City (Children’s Mercy Hospital)
  • Seattle (Children’s Hospital, Seattle)

The combination trial is taking place at six locations:

  • Saint Louis (Saint Louis University VTEU, the lead site for this trial)
  • Atlanta (Emory University VTEU)
  • Cincinnati (Cincinnati Children’s Hospital VTEU)
  • Houston (Baylor College of Medicine VTEU)
  • Iowa City (University of Iowa VTEU)
  • Galveston (University of Texas Medical Branch)
6. Who makes the vaccines being tested in the pediatric trials?

Both trials are using a 2009 H1N1 flu vaccine made by Sanofi Pasteur in Swiftwater, Pennsylvania. The combination trial involves a licensed seasonal flu vaccine made by the same company.

7. Do the vaccines used in the pediatric trials contain thimerosal or adjuvants?

No. The 2009 H1N1 influenza vaccine and the seasonal influenza vaccine used in these trials do not contain thimerosal or adjuvants.

For more information, visit NIAID's Vaccine portal, where you also can find information about adjuvants and thimerosal.

8. What data did the Safety Monitoring Committee evaluate to determine that the trials could proceed in children?

The Safety Monitoring Committee assessed initial safety data from the ongoing trials of 2009 H1N1 influenza vaccines from more than 500 healthy adult and elderly volunteers.
All clinical protocols are also reviewed and approved by the U.S. Food and Drug Administration (FDA) before enrolling any volunteers.

9. Have some children enrolled in the study received a placebo injection? If so, will those children be offered the 2009 H1N1 or seasonal influenza vaccines after the trial is concluded?

No. Placebos are not being used in the pediatric trials.

10. What did early results from the dosing trial show?

Preliminary analysis of blood samples from a small group of trial participants showed that a single 15-microgram dose of a non-adjuvanted 2009 H1N1 influenza vaccine generated an immune response that is expected to be protective against 2009 H1N1 influenza virus in the majority of 10-to 17-year olds, 8 to 10 days following vaccination. Younger children generally had a less robust early response to the vaccine.

The preliminary results are based on blood samples taken 8 to 10 days after the first vaccination. Immune responses were strongest among the oldest children, those 10-to 17-years old. In this group of 25 children, a strong immune response was seen in 76 percent who received one 15-microgram dose of 2009 H1N1 influenza vaccine. Among 25 volunteers aged 3 to 9 years old, a strong immune response was seen in 36 percent of those given 15 micrograms of vaccine. In the youngest group, 20 children between 6 months and 35 months old, a single 15-microgram dose of vaccine produced a strong immune response in 25 percent of recipients.

These preliminary results were announced on September 21, 2009.

For more information, visit NIAID's Vaccine portal, where you also can find information about adjuvants and thimerosal.

For more information about influenza, including H1N1, visit NIAID's Flu portal.

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 website.

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 September 20, 2009

Last Reviewed September 20, 2009