Half-Dose Flu Vaccine Study in Healthy Adults

Evaluation of the Immunogenicity of Low Dose Trivalent Inactivated Influenza Vaccine in Healthy Adults

It appears likely that there will be a delay and possibly a reduction in the amount of influenza vaccine available for the 2000-2001 influenza season. One possible way of increasing the availability of influenza vaccine for this year is to use a half-dose in healthy adults. The objective of this study is to determine if the immune system responds to a half-dose the same way it responds to a whole dose. This study will use the currently approved inactivated influenza vaccine in healthy adults ages 18 to 49 years old. If the immune response to the half-dose is not significantly different than the immune response generated to the whole dose, this could be a strategy to extend the amount of vaccine that could be available in this age group.

Eligible subjects will be randomized to receive a single intramuscular injection of either a half-dose or a whole dose of a currently approved influenza virus vaccine in their arm. Prior to vaccination, subjects will have one tube of blood drawn. Subjects will be given a 3-day diary card to record any symptoms they may experience and asked to return for a second and final visit approximately 21 days following vaccination. A second blood draw will be done.

Inclusion Criteria: Volunteers may be eligible for this trial if they: Are able to and have given informed consent. Are able to understand and comply with all study procedures and to complete study diary. Are aged 18 to 49 years. Are female, and are not pregnant. Are available for all study visits. Exclusion Criteria: Volunteers will not be eligible for this trial if they: Are allergic to eggs or egg products. Have a current chronic medical condition for which influenza vaccine is normally recommended. Have received experimental vaccines or medications within 30 days of study entry. Have received parenteral immunoglobulin within 30 days of study entry.