Comparative Study of Influenza Vaccines in Healthy Adults (The FLUVACS Study)

Principal Investigator

Arnold Monto

Co-Investigator

Suzanne Ohmit

Funding Sources

National Institutes of Health (NIH), Sanofi Pasteur

About this Project

FLUVACS was a randomized, double-blind, placebo-controlled, community based trial conducted over a four year period beginning in fall 2004. The primary study objectives were to examine the absolute (vs. placebo) and relative (one vaccine vs. the other) efficacies of the inactivated and live-attenuated influenza vaccines in preventing symptomatic laboratory-confirmed influenza. Eligible subjects were healthy men and women (without co-morbidities linked to vaccine recommendations) aged 18-49 years. Subjects were recruited from the community at university sites in Michigan. Participants were vaccinated based on random assignment of intervention at first enrollment (inactivated vaccine or matching placebo given by intramuscular injection, or live-attenuated vaccine or matching placebo given by nasal spray). Each year, blood specimens were collected immediately prior to vaccination, 30 days after vaccination and at the end of the influenza season; serologic assays were used to evaluate antibody response to influenza vaccination and infection. From November through April each year, participants reported influenza-like illnesses meeting a case definition. Throat swab specimens were collected for virus identification by isolation in cell culture and real-time PCR. Illnesses were followed to collect information on the presence and severity of symptoms, duration of illness, and whether the illness was medically attended. Each year, risk of symptomatic influenza illnesses defined by multiple laboratory endpoints (rt-PCR, culture, serology) were estimated and compared by intervention group. The results of the efficacy analyses from study years one, two and four have been published and can be found in the publications section, along with companion publications examining adverse reactions to vaccine receipt and characteristics of vaccine failures. Additional analyses will examine duration of vaccine protection and serologic predictors of