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Flu (Influenza)

H1N1 Vaccine Clinical Studies: Adults—Giving Seasonal and H1N1 Vaccines Together

Description

This trial started on August 7, 2009 with 800 participants (400 healthy adults age 18 through 64 and 400 healthy adults aged 65 or older.) The purpose of the study is to look at the safety and immune response in healthy adult volunteers who are given the seasonal flu vaccine along with a 15 microgram dose of 2009 H1N1 vaccine. The H1N1 vaccine was given to different sets of volunteers before, after, or at the same time as the seasonal flu vaccine.

One goal of the study is to determine whether receiving 2009 H1N1 influenza vaccine at the same time as seasonal influenza vaccine has any effect on the body’s ability to produce an immune response predictive of protection against 2009 H1N1 influenza virus. A second goal is to determine if the order of vaccination affects the body’s immune response when the two vaccines are given 21 days apart.
The trials are being conducted at the Baylor College of Medicine, Cincinnati Children’s Hospital, Hope Clinic of Emory Vaccine Center, and Saint Louis University.

Current Status

Early data released October 9, 2009 based on results from 50 volunteers shows simultaneous administration of injected seasonal flu and H1N1 vaccines does not impair the immune response to either vaccine.

In one of the four groups enrolled in this trial, each volunteer received an injection of inactivated seasonal influenza vaccine as well as an injection of inactivated 2009 H1N1 influenza vaccine at the first clinic visit. Study investigators analyzed early data from blood samples of some volunteers in this group. Among 25 volunteers aged 18 through 64 years, 76 percent showed a robust immune response to the 2009 H1N1 influenza vaccine. Among 25 volunteers aged 65 years or older, 80 percent developed a robust immune response to the 2009 H1N1 influenza vaccine.

These early results support current public health recommendations that endorse simultaneous administration of injectable versions of seasonal influenza and 2009 H1N1 influenza vaccines as one—but not the only—option. The early data from this trial also indicate that both vaccines have been well tolerated.