The purpose of this study was to evaluate the safety, tolerability, and immunogenicity of the Merck 0657nI S. aureus vaccine (V710) either with or without Merck Aluminum Adjuvant (MAA).

Inclusion criteria:

• Participant was in good physical health
• Participant was able to understand study procedures and agreed to participate in the study by providing written informed consent.
• Participant was willing and able to participate in the entire study duration planned for up to 12 months (~360 days).
• Female participants of reproductive potential were required to have a negative urine pregnancy test immediately prior to study vaccination. Female participants of reproductive potential must have used an acceptable method of birth control for 2 weeks prior to enrollment, and agreed to use an acceptable method of birth control for 1 month after vaccination.

Exclusion criteria:

• Participant suffered from a chronic skin condition that predisposed the individual to the development of chronic skin or soft-tissue infections (e.g., psoriasis, chronic granulomatous disease, atopic dermatitis).
• Participant developed a serious infection (e.g., bacteremia, pneumonia, mediastinitis) attributed to S. aureus in the 12 months prior to screening.
• Participant had a history of anaphylaxis to aluminum-containing adjuvant or other vaccine components.
• Participant had a temperature of ≥100.4ºF (≥38.0ºC), oral equivalent, within 48 hours prior to receipt of V710.
• Participant had received a live virus vaccine within 30 days prior to receipt of V710 or was scheduled to receive vaccination with a live virus vaccine within 30 days following study entry.
• Participant had received any other licensed vaccine (including non-live virus vaccines) within 14 days prior to receipt of V710 or was scheduled to receive any other licensed vaccine (including non-live virus vaccines) within 30 days following study entry.
• Participant had received V710 in a prior clinical study (Merck V710 Protocol 001).
• Participant was administered immunoglobulin or blood product within 90 days prior to receipt of V710 or was scheduled to receive such products within 30 days following study entry.
• Participant had received treatment with systemic (intramuscular, oral, or intravenous) corticosteroids or another immunosuppressive medication (e.g., calcineurin inhibitors, mycophenolate, azathioprine) or biological agents (e.g., rituximab) in the 14 days prior to receipt of V710 or was anticipated to receive such medications for a chronic medical condition during the course of the study.
• Participant had a condition that required active medical intervention or monitoring to avert serious danger to the participant's health or well-being, such as diabetes mellitus, autoimmune disease, or clinically significant chronic medical conditions that were considered progressive, including but not limited to: coronary artery disease, congestive heart failure, cardiomyopathy, progressive valvular heart disease, chronic obstructive pulmonary disease, pulmonary fibrosis, active peptic ulcer disease, chronic renal disease, chronic hepatic disease, multiple sclerosis, progressive neuropathies, or seizure disorder requiring therapy in the past 3 years.
• Participant had known or suspected impairment of immunologic function including, but not limited to, the following conditions: autoimmune disease, diabetes mellitus, endstage renal disease, hepatic insufficiency/cirrhosis, splenectomy, or human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS).
• Participant had a condition in which repeated venipuncture or injections posed more than minimal risk for the subject, such as hemophilia, other severe coagulation disorders, or significantly impaired venous access.
• Participant was pregnant or breastfeeding, or planning to conceive within the 12-month study duration period.
• Participant had clinically significant abnormalities based on the participant or physical examination.
• Participant had recent history (within the past 5 years) or current evidence of drug or alcohol abuse.
• Participant had a major psychiatric illness, including any history of schizophrenia or severe psychosis, bipolar disorder requiring therapy, or any subject with suicidal ideation within the previous 3 years.
• Participant was legally or mentally incapacitated.
• Participant had participated in another clinical study in the past 4 weeks, or participant planned to participate in a treatment-based study or study in which an invasive procedure was to be performed during the first 3 months of this study (through Day 84).
• Participant had a history of any condition which, in the opinion of the investigator, posed an additional risk for the subject or confounded the results of the study.