Pediatric H1N1 Vaccine Clinical Studies

Description

On August 18, 2009, NIAID began two trials of 2009 H1N1 influenza vaccine in children between 6 months and 17 years of age. These trials enrolled about 1200 children.

The trials began after NIAID's Safety Monitoring Committee reviewed data from more than 500 volunteers enrolled in NIAID trials of 2009 H1N1 influenza vaccines in healthy adults. The Safety Monitoring Committee is a panel of outside experts convened by NIAID. Experts on this independent committee are recognized in the fields of pediatrics, infectious diseases and vaccine practice and safety. The Safety Monitoring Committee determined that the pediatric trials could begin, and NIAID agreed with those recommendations on August 17, 2009.

Pediatric 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. Data from the trial is being compared for three age groups: children 6 months to 35 months old; 3 to 9 years old; and 10 to 17 years old.

The trial enrolled about 600 children at five locations nationwide: University of Maryland School of Medicine, Vanderbilt University, Duke University, Children's Mercy Hospital, Children's Hospital, Seattle.

Current Status

On November 2, 2009, NIAID announced that interim results from the pediatric trials indicated that, in children, 2009 H1N1 vaccine works like seasonal flu vaccine. The results built upon preliminary results from a subset of volunteers announced September 21, 2009 and mirror results seen in adults.

Interim analysis of all available blood samples from the trial showed that a single 15-microgram dose of a 2009 H1N1 influenza vaccine-the same dose that is in the seasonal flu vaccine-generated an immune response likely to protect against 2009 H1N1 influenza virus in the majority of 10- to 17- year-olds 21 days following vaccination. A strong immune response was seen in 94 percent who received one 15-microgram dose of vaccine. These results were similar to those reported in clinical trials of healthy adults. The trial data continue to support the recommendation that children 10 years of age and older should receive one 15-microgram dose of vaccine.

Younger children, those between 6 months to 9 years of age, had a less robust early response to the vaccine.

Data obtained eight to 10 days after the second vaccine dose compared with results obtained 21 days after their first vaccine dose were as follows:

Among the youngest children (6 to 35 months), 100 percent had a robust immune response after the second 15-microgram dose compared with only 25 percent three weeks after the first dose.
In children aged 3 through 9 years old, 94 percent had a robust response after the second 15-microgram dose compared with only 55 percent three weeks after the first dose.
In general, the immune responses in children receiving two 15-microgram doses and those receiving two 30-microgram doses of vaccine were similar, suggesting that receipt of two 15 microgram doses is adequate to elicit a strong immune response.

The trial data continue to support the recommendation that children 9 years of age and younger should receive two 15-microgram doses of 2009 H1N1 vaccine.

Pediatric Co-Administration Trial (Seasonal Flu and H1N1 Vaccines Together)

This 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 the seasonal flu vaccine, 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 about 600 children at six locations nationwide: Saint Louis University, Emory University, Cincinnati Children's Hospital, Baylor College of Medicine, University of Iowa, and the University of Texas Medical Branch, Galveston.

Trials in HIV+ Newborns and Children and Trials in Children with Asthma

Separate clinical trials are now enrolling children and youth aged 4 to 24 years who were infected with HIV at birth and children over 12 with mild, moderate or severe asthma. For more information see the sections on HIV-Infected Individuals and People with Asthma trials.