Completed

A Phase II, Multicenter, Randomized, Observer-Blind, Placebo-Controlled Study to Evaluate the Immunogenicity, Safety and Tolerability of CSL's 2009 H1N1 Influenza Vaccine (CSL425) in Healthy Adults Aged 18 Years and Older

What is being tested

CSL425

+ Placebo

Biological

Who is being recruted

Infections+4

+ Influenza, Human

+ Orthomyxoviridae Infections

Over 18 Years

+3 Eligibility Criteria

See all eligibility criteria

How is the trial designed

Prevention Study

Placebo-ControlledPhase 2

Interventional

Study Start: August 2009

See protocol details

Summary

Principal SponsorSeqirus

Last updated: January 27, 2026

Sourced from a government-validated database.Claim as a partner

Study start date: August 1, 2009

Actual date on which the first participant was enrolled.

The purpose of this study is to determine whether CSL425 is a safe and effective vaccine for eliciting an immune response to H1N1 influenza in healthy adults

Official TitleA Phase II, Multicenter, Randomized, Observer-Blind, Placebo-Controlled Study to Evaluate the Immunogenicity, Safety and Tolerability of CSL's 2009 H1N1 Influenza Vaccine (CSL425) in Healthy Adults Aged 18 Years and Older

NCT00958126

Principal SponsorSeqirus

Last updated: January 27, 2026

Sourced from a government-validated database.Claim as a partner

Protocol

This section provides details of the study plan, including how the study is designed and what the study is measuring.

Design Details

1313 patients to be enrolled

Total number of participants that the clinical trial aims to recruit.

Prevention Study

Prevention studies aim to stop a disease from developing. They often involve people at risk and test things like vaccines, lifestyle changes, or preventive medications.

Eligibility

Researchers look for people who fit a certain description, called eligibility criteria: person's general health condition or prior treatments.

Conditions

Criteria

Any sex

Biological sex of participants that are eligible to enroll.

Over 18 Years

Range of ages for which participants are eligible to join.

Healthy volunteers allowed

If individuals who are healthy and do not have the condition being studied can participate.

Conditions

Pathology

InfectionsInfluenza, HumanOrthomyxoviridae InfectionsRespiratory Tract DiseasesRespiratory Tract InfectionsRNA Virus InfectionsVirus Diseases

Criteria

2 inclusion criteria required to participate

Male or female aged 18 and older, inclusive, at the time of providing informed consent.

Females of child bearing potential (i.e., ovulating, pre-menopausal, not surgically sterile) must be abstinent or be willing to use a medically accepted contraceptive regimen for the duration of the study. Females of child bearing potential must return a negative urine pregnancy test result at enrolment and prior to each study vaccination.

1 exclusion criteria prevent from participating

Known hypersensitivity to a previous dose of influenza virus vaccine or allergy to eggs, chicken protein, thimerosal, neomycin, polymyxin, or any components of the Study Vaccine.

Study Plan

Find out more about all the medication administered in this study, their detailed description and what they involve.

Treatment Groups

Study Objectives

4 intervention groups are designated in this study

25% chance of being blinded to the placebo group

Treatment Groups

Group I

Experimental

7.5 mcg of hemagglutinin antigen per dose. 0.25 mL intramuscular injection into the deltoid region of the arm on Day 0 and Day 21

Group II

Experimental

15 mcg of hemagglutinin antigen per dose. 0.25 mL intramuscular injection into the deltoid region of the arm on Day 0 and Day 21.

Group III

Experimental

30 mcg of hemagglutinin antigen per dose. 0.5 mL intramuscular injection into the deltoid region of the arm on Day 0 and Day 21

Group IV

Placebo

Vaccine diluent. 0.5 mL intramuscular injection into the deltoid region of the arm on Day 0 and Day 21.

Study Objectives

Primary Objectives

Secondary Objectives

Study Centers

These are the hospitals, clinics, or research facilities where the trial is being conducted. You can find the location closest to you and its status.

This study has 11 locations

Suspended

Study Site

Huntsville, United StatesOpen Study Site in Google Maps

Suspended

Study Site

San Diego, United States

Suspended

Study Site

Melbourne, United States

Suspended

Study Site

Peoria, United States

Completed11 Study Centers