A Phase I Study to Evaluate the Safety, Reactogenicity, and Humoral Immune Responses to an Inactivated H5N1 Influenza Vaccine

Since 1997, avian H5N1 influenza in Southeast Asia has caused several human infections and has a high mortality rate. Experts warn that the next influenza pandemic is imminent and could be severe and prevention and control will depend on the rapid production and worldwide distribution of specific pandemic influenza candidate vaccines. An H5N1 influenza vaccine was successfully produced from whole virus grown in MDCK (Madin-Darby canine kidney) cells. These purified inactivated vaccine antigens were safe and could induce immune responses in animal studies. Moreover, when formulated in aluminum phosphate a stronger response was generated even at low doses in animals (Chong et al., 2008; Hu et al., 2008). However, further investigations are necessary before their human safety and immunogenicity can be established. This human phase I clinical study, therefore, evaluates the safety and immunogenicity of adjuvanted H5N1 virion influenza vaccine.

Inclusion criteria

• Male or female ≥20 and ≤60 years of age
• In good health as determined by medical history, physical examination, and clinical judgment of the investigator
• Willing and able to comply with all required study visits and follow-up required by this protocol
• Must provide written informed consent

Exclusion criteria

• Known or potential exposure to avian influenza virus or any H5N1 HA antigen vaccine
• Had any influenza vaccine within 6 months
• Administered with any vaccine within 30 days
• A history of hypersensitivity to vaccines or inflammatory or degenerative neurological disease
• Receiving chronic administration of immunosuppressants or other immune-modifying drugs within 6 months
• Known HIV, hepatitis B (HBsAg) or hepatitis C seropositivity
• Any medical illness including clinically significant acute pulmonary, cardiovascular, hepatic or renal functional abnormality, as determined by physical examination or laboratory screening tests
• Receiving immunoglobulins and/or any blood products within the three months
• Acute disease at the time of enrolment
• Psychiatric, addictive, or any disorder, which may compromise the ability to give a truly informed consent for participation of this study or adequate compliance
• Breast feeding or pregnant women