A Study to Evaluate the Efficacy, Immunogenicity and Safety in a Sporozoite Challenge Model of a Fractional Booster Dose of GSK Biologicals' Candidate Malaria Vaccine Administered to Previously Vaccinated Healthy Malaria-naïve Adults

Exclusion Criteria

• •For all subjects except the infectivity control subjects:
• •Any medical condition that in the judgment of the investigator would make intramuscular injection unsafe.
• •History of any reaction or hypersensitivity likely to be exacerbated by any component of the vaccine.
• •History of anaphylaxis post-vaccination.
• •For all subjects:
• •Use of any investigational or non-registered product other than the study vaccine during the period starting 30 days before Day 1 (Day -29 to Day 1) (for P-Fx and NP-Fx groups)/before the malaria challenge (for infectivity control subjects), or planned use during the study period.
• •Chronic administration of immunosuppressants or other immune-modifying drugs during the period starting six months prior to Day 1 (for P-Fx and NP-Fx groups) or malaria challenge (for infectivity control subjects). For corticosteroids, this will mean prednisone ≥20 mg/day, or equivalent. Inhaled and topical steroids are allowed.
• •Administration of long-acting immune-modifying drugs at any time during the study period.
• •Chronic use of antibiotics with anti-malarial effects.
• •Planned administration/administration of a vaccine not foreseen by the study protocol in the period within seven days of Day 1 (for P-Fx and NP-Fx groups) or the malaria challenge (for infectivity control subjects).
• •Concurrently participating in another clinical study, at any time during the study period, in which the subject has been or will be exposed to an investigational or a non-investigational vaccine/product.
• •Seropositive for Human Immunodeficiency Virus, Hepatitis B surface antigen or Hepatitis C Virus.
• •Planned travel to malaria endemic areas during the study period.
• •Any confirmed or suspected immunosuppressive or immunodeficient condition, based on medical history and physical examination.
• •History of any reaction or hypersensitivity that would prevent the subject from utilizing all of the following: chloroquine, atovaquone/proguanil, artemether/lumefantrine.
• •Current use of medications known to cause drug reactions that would prevent the subject from utilizing any of the following: chloroquine, atovaquone/proguanil, artemether/lumefantrine.
• •History of severe reactions to mosquito bites.
• •Acute disease and/or fever at the time of enrollment.
• •* Fever is defined as temperature ≥37.5°C/99.5°F for oral, axillary or tympanic route.
• •* Subjects with a minor illness without fever may be enrolled at the discretion of the investigator.
• •Hepatomegaly, right upper quadrant abdominal pain or tenderness.
• •Any abnormal baseline laboratory screening tests: ALT, AST, creatinine, hemoglobin, platelet count, total WBC, out of normal range.
• •Personal history of auto-immune disease.
• •Administration of immunoglobulins and/or any blood products during the period starting three months before Day 1 (for P-Fx and NP-Fx groups)/the malaria challenge (for infectivity control subjects), or planned administration during the study period.
• •Pregnant or lactating female.
• •Female planning to become pregnant or planning to discontinue contraceptive precautions.
• •History of chronic alcohol consumption and/or drug abuse.
• •History of blood donation within 56 days preceding enrollment.
• •Any other significant finding that in the opinion of the investigator would increase the risk of having an adverse outcome from participating in this study.
• •Acute or chronic, clinically significant pulmonary, cardiovascular, hepatic or renal functional abnormality, as determined by physical examination or laboratory screening tests.
• •Evidence of increased cardiovascular disease risk, "moderate" or "high", according to the National Health And Nutrition Examination Survey I (NHANES I) criteria.
• •Only for infectivity control subjects:
• •Previous vaccination against malaria.
• •History of splenectomy.
• •Family history of congenital or hereditary immunodeficiency.
• •Major congenital defects.
• •Serious chronic illness.
• •History of any neurological disorders or seizures.
• •Diagnosed with malaria within the last 5 years (inclusive).