Blood was collected from participants for testing in the HAI assay with Influenza H1N1 2009 virus as the assay antigen. A participant met the threshold of a 4-fold rise in titer if the Day 0 titer was less than 1:10 (the assay's lowest level of detection) and the Day 8 post first H1N1 vaccination titer was 1:40 or greater, or the Day 0 titer was greater than or equal to 1:10 and the Day 8 titer was an increase by 4-fold or more.

Participants who received the H1N1 vaccination and from whom blood was collected are included. One participant was excluded due to an eligibility deviation. This outcome restricts to age stratum.

Blood was collected from participants for testing in the HAI assay with Influenza H1N1 2009 virus as the assay antigen. A participant met the threshold of a 4-fold rise in titer if the Day 0 titer was less than 1:10 (the assay's lowest level of detection) and the Day 21 post first H1N1 vaccination titer was 1:40 or greater, or the Day 0 titer was greater than or equal to 1:10 and the Day 21 titer was an increase by 4-fold or more.

Participants who received the H1N1 vaccination and from whom blood was collected within 7 days of the window are included. One participant was excluded due to eligibility deviation and two due to receipt of off-study vaccines. Analyses are as treated. This outcome restricts to age stratum.

Blood was collected from participants for testing in the HAI assay with Influenza H1N1 2009 virus as the assay antigen. A participant met the threshold of a 4-fold rise in titer if the Day 0 titer was less than 1:10 (the assay's lowest level of detection) and the Day 8 post first H1N1 vaccination titer was 1:40 or greater, or the Day 0 titer was greater than or equal to 1:10 and the Day 8 titer was an increase by 4-fold or more.

Participants who received the H1N1 vaccination and from whom blood was collected are included. One participant was excluded due to influenza-like illness. This outcome restricts to age stratum.

Blood was collected from participants for testing in the HAI assay with Influenza H1N1 2009 virus as the assay antigen. A participant met the threshold of a 4-fold rise in titer if the Day 0 titer was less than 1:10 (the assay's lowest level of detection) and the Day 21 post first H1N1 vaccination titer was 1:40 or greater, or the Day 0 titer was greater than or equal to 1:10 and the Day 21 titer was an increase by 4-fold or more.

Participants who received the H1N1 vaccination and from whom blood was collected within 7 days of the window are included. One participant was excluded due to influenza-like illness. Analyses are as treated. This outcome restricts to age stratum.

Serious adverse events included any untoward medical occurrence that resulted in death; was life threatening; was a persistent/significant disability/incapacity; required in-patient hospitalization or prolongation thereof; resulted in a congenital anomaly/birth defect; may have jeopardized the participant or required intervention to prevent one of these outcomes; or was described as Guillain-Barré Syndrome. Association to vaccination was determined by a study clinician licensed to make medical diagnoses.

All participants receiving the first vaccination are included in the safety cohort. Analyses are as treated.

Blood was collected from all participants 8 days after second vaccination for testing in the HAI assay with Influenza H1N1 2009 virus as the assay antigen. Each sample was tested at least twice according to standard operating procedures and the result of each replicate reported. A participant is counted if the geometric mean of the replicate values was 1:40 or greater.

Participants who received both H1N1 vaccinations and from whom blood was collected are included. One participant was excluded due to eligibility deviation, one due to receipt of the wrong second dose, and two due to receipt of off-study vaccines. Analyses are as treated. This outcome restricts to age stratum.

Blood was collected from all participants 21 days after second vaccination for testing in the HAI assay with Influenza H1N1 2009 virus as the assay antigen. Each sample was tested at least twice according to standard operating procedures and the result of each replicate reported. A participant is counted if the geometric mean of the replicate values was 1:40 or greater.

Participants who received both H1N1 vaccinations and from whom blood was collected within 7 days of window are included. One participant was excluded due to eligibility deviation, one due to receipt of the wrong second dose, and two due to receipt of off-study vaccines. Analyses are as treated. This outcome restricts to age stratum.

Blood was drawn 8-10 days after vaccination to assess laboratory parameters at a central laboratory. Adverse events (AE) were any values that were Grade 1 or greater for the following parameters: prothrombin time (AE >12.6 seconds), partial thromboplastin time (>40.7 seconds), platelets (>=401,000 or <=129,000 cells/square millimeter), white blood cells (>10,800 or <3800 cells/microliter), neutrophils (>8000 or <1800 cells/microliter), and lymphocytes(>4100 or <850 cells/microliter). These parameters were not evaluated prior to enrollment as an assessment of eligibility.

Participants who received the first vaccination and had blood collected with results reported at the timepoint are included. Analyses are as treated.

Blood was drawn 8-10 days after vaccination to assess laboratory parameters at a central laboratory. Adverse events (AE) were any values that were Grade 1 or greater for the following parameters: prothrombin time (AE >12.6 seconds), partial thromboplastin time (>40.7 seconds), platelets (>=401,000 or <=129,000 cells/square millimeter), white blood cells (>10,800 or <3800 cells/microliter), neutrophils (>8000 or <1800 cells/microliter), and lymphocytes(>4100 or <850 cells/microliter). These parameters were not evaluated prior to enrollment as an assessment of eligibility.

Participants who received at least the first vaccination and had blood collection at the timepoint are included. Analyses are as treated.

Blood was drawn 8-10 days after vaccination to assess laboratory parameters at a central laboratory. Adverse events (AE) were any values that were Grade 1 or greater for the following parameters: sodium (AE >146 or <135 mEq/L), potassium (>5.3 or <3.5 mEq/L), creatinine (>1.4 mg/dL), Alanine transaminase (>52.7 U/L), Albumin (<3.2 g/dL), and total protein (<6.0 g/dL participants age 18-64 years, <5.8 g/dL participants age 65 years and older). These parameters were not evaluated prior to enrollment as an assessment of eligibility.

Participants who received the first vaccination and had blood collected with results reported at the timepoint are included. Analyses are as treated.

Blood was collected from all participants 180 days after second vaccination for testing in the HAI assay with Influenza H1N1 2009 virus as the assay antigen. Each sample was tested at least twice according to standard operating procedures and the result of each replicate reported. A participant is counted if the geometric mean of the replicate values was 1:40 or greater.

Participants who received both H1N1 vaccinations and from whom blood was collected within 14 days of window are included. Two participants were excluded due to eligibility deviations, one due to receipt of the wrong second dose, and two due to receipt of off-study vaccines. Analyses are as treated. This outcome restricts to age stratum.

Blood was collected from all participants 270 days after second vaccination for testing in the HAI assay with Influenza H1N1 2009 virus as the assay antigen. Each sample was tested at least twice according to standard operating procedures and the result of each replicate reported. A participant is counted if the geometric mean of the replicate values was 1:40 or greater.

Participants who received both H1N1 vaccinations and from whom blood was collected within 14 days of window are included. Two participants were excluded due to eligibility deviations, one due to receipt of the wrong second dose, and two due to receipt of off-study vaccines. Analyses are as treated. This outcome restricts to age stratum.

Blood was collected from all participants 8 days after second vaccination for testing in the HAI assay with Influenza H1N1 2009 virus as the assay antigen. Each sample was tested at least twice according to standard operating procedures and the result of each replicate reported. A participant is counted if the geometric mean of the replicate values was 1:40 or greater.

Participants who received both H1N1 vaccinations and from whom blood was collected are included. One participant was excluded due to influenza-like illness and one due to receipt of off-study vaccine. Analyses are as treated. This outcome restricts to age stratum.

Blood was collected from all participants 21 days after second vaccination for testing in the HAI assay with Influenza H1N1 2009 virus as the assay antigen. Each sample was tested at least twice according to standard operating procedures and the result of each replicate reported. A participant is counted if the geometric mean of the replicate values was 1:40 or greater.

Participants who received both H1N1 vaccinations and from whom blood was collected within 7 days of window are included. One participant was excluded due to influenza-like illness and two due to receipt of off-study vaccines. Analyses are as treated. This outcome restricts to age stratum.

Blood was collected from all participants 180 days after second vaccination for testing in the HAI assay with Influenza H1N1 2009 virus as the assay antigen. Each sample was tested at least twice according to standard operating procedures and the result of each replicate reported. A participant is counted if the geometric mean of the replicate values was 1:40 or greater.

Participants who received both H1N1 vaccinations and from whom blood was collected within 14 days of window are included. One participant was excluded due to influenza-like illness and two due to receipt of off-study vaccines. Analyses are as treated. This outcome restricts to age stratum.

Blood was collected from all participants 270 days after second vaccination for testing in the HAI assay with Influenza H1N1 2009 virus as the assay antigen. Each sample was tested at least twice according to standard operating procedures and the result of each replicate reported. A participant is counted if the geometric mean of the replicate values was 1:40 or greater.

Participants who received both H1N1 vaccinations and from whom blood was collected within 14 days of window are included. One participant was excluded due to influenza-like illness and two due to receipt of off-study vaccines. Analyses are as treated. This outcome restricts to age stratum.

Blood was collected from participants for testing in the HAI assay with Influenza H1N1 2009 virus as the assay antigen. A participant met the threshold of a 4-fold rise in titer if the Day 0 titer was less than 1:10 (the assay's lowest level of detection) and the Day 8 post second H1N1 vaccination titer was 1:40 or greater, or the Day 0 titer was greater than or equal to 1:10 and the Day 8 titer was an increase by 4-fold or more.

Participants who received both H1N1 vaccinations and from whom blood was collected are included. One participant was excluded due to eligibility deviation, one due to receipt of the wrong second dose, and two due to receipt of off-study vaccines. Analyses are as treated. This outcome restricts to age stratum.

Blood was drawn 8-10 days after vaccination to assess laboratory parameters at a central laboratory. Adverse events (AE) were any values that were Grade 1 or greater for the following parameters: sodium (AE >146 or <135 mEq/L), potassium (>5.3 or <3.5 mEq/L), creatinine (>1.4 mg/dL), Alanine transaminase (>52.7 U/L), Albumin (<3.2 g/dL), and total protein (<6.0 g/dL participants age 18-64 years, <5.8 g/dL participants age 65 years and older). These parameters were not evaluated prior to enrollment as an assessment of eligibility.

Participants who received at least the first vaccination and had blood collected with results reported at the timepoint are included. Analyses are as treated.

Participants maintained a memory aid to record daily the occurrence of systemic symptoms of feverishness, malaise, myalgia, headache, nausea, chills, arthralgia, and shivering for 8 days (Day 0-7) after vaccination based on their interference with daily activities. Participants are counted if they reported experiencing the symptom at any severity on any of the 8 days.

Participants who received the first vaccination are included. Analyses are as treated.

Participants maintained a memory aid to record daily the occurrence of systemic symptoms of feverishness, malaise, myalgia, headache, nausea, chills, arthralgia, and shivering for 8 days (Day 0-7) after vaccination based on their interference with daily activities. Participants are counted if they reported experiencing the symptom at any severity on any of the 8 days.

Participants who received the second vaccination are included. Analyses are as treated.

Blood was collected from participants for testing in the HAI assay with Influenza H1N1 2009 virus as the assay antigen. A participant met the threshold of a 4-fold rise in titer if the Day 0 titer was less than 1:10 (the assay's lowest level of detection) and the Day 21 post second H1N1 vaccination titer was 1:40 or greater, or the Day 0 titer was greater than or equal to 1:10 and the Day 21 titer was an increase by 4-fold or more.

Participants who received both H1N1 vaccinations and from whom blood was collected within 7 days of the window are included. One participant was excluded due to eligibility deviation, one due to receipt of the wrong second dose, and two due to receipt of off-study vaccines. Analyses are as treated. This outcome restricts to age stratum.

Blood was collected from participants for testing in the HAI assay with Influenza H1N1 2009 virus as the assay antigen. A participant met the threshold of a 4-fold rise in titer if the Day 0 titer was less than 1:10 (the assay's lowest level of detection) and the Day 180 post second H1N1 vaccination titer was 1:40 or greater, or the Day 0 titer was greater than or equal to 1:10 and the Day 180 titer was an increase by 4-fold or more.

Participants who received both H1N1 vaccinations and from whom blood was collected within 14 days of the window are included. Two participants were excluded due to eligibility deviations, one due to receipt of the wrong second dose, and two due to receipt of off-study vaccines. Analyses are as treated. This outcome restricts to age stratum.

Blood was collected from participants for testing in the HAI assay with Influenza H1N1 2009 virus as the assay antigen. A participant met the threshold of a 4-fold rise in titer if the Day 0 titer was less than 1:10 (the assay's lowest level of detection) and the Day 270 post second H1N1 vaccination titer was 1:40 or greater, or the Day 0 titer was greater than or equal to 1:10 and the Day 270 titer was an increase by 4-fold or more.

Participants who received both H1N1 vaccinations and from whom blood was collected within 14 days of the window are included. Two participants were excluded due to eligibility deviations, one due to receipt of the wrong second dose, and two due to receipt of off-study vaccines. Analyses are as treated. This outcome restricts to age stratum.

Blood was collected from participants for testing in the HAI assay with Influenza H1N1 2009 virus as the assay antigen. A participant met the threshold of a 4-fold rise in titer if the Day 0 titer was less than 1:10 (the assay's lowest level of detection) and the Day 8 post second H1N1 vaccination titer was 1:40 or greater, or the Day 0 titer was greater than or equal to 1:10 and the Day 8 titer was an increase by 4-fold or more.

Participants who received both H1N1 vaccinations and from whom blood was collected are included. One participant was excluded due to influenza-like illness and one due to receipt of off-study vaccine. Analyses are as treated. This outcome restricts to age stratum.

Blood was collected from participants for testing in the HAI assay with Influenza H1N1 2009 virus as the assay antigen. A participant met the threshold of a 4-fold rise in titer if the Day 0 titer was less than 1:10 (the assay's lowest level of detection) and the Day 21 post second H1N1 vaccination titer was 1:40 or greater, or the Day 0 titer was greater than or equal to 1:10 and the Day 21 titer was an increase by 4-fold or more.

Participants who received both H1N1 vaccinations and from whom blood was collected within 7 days of the window are included. One participant was excluded due to influenza-like illness and two due to receipt of off-study vaccines. Analyses are as treated. This outcome restricts to age stratum.

Blood was collected from participants for testing in the HAI assay with Influenza H1N1 2009 virus as the assay antigen. A participant met the threshold of a 4-fold rise in titer if the Day 0 titer was less than 1:10 (the assay's lowest level of detection) and the Day 180 post second H1N1 vaccination titer was 1:40 or greater, or the Day 0 titer was greater than or equal to 1:10 and the Day 180 titer was an increase by 4-fold or more.

Participants who received both H1N1 vaccinations and from whom blood was collected within 14 days of the window are included. One participant was excluded due to influenza-like illness and two due to receipt of off-study vaccines. Analyses are as treated. This outcome restricts to age stratum.

Blood was collected from participants for testing in the HAI assay with Influenza H1N1 2009 virus as the assay antigen. A participant met the threshold of a 4-fold rise in titer if the Day 0 titer was less than 1:10 (the assay's lowest level of detection) and the Day 270 post second H1N1 vaccination titer was 1:40 or greater, or the Day 0 titer was greater than or equal to 1:10 and the Day 270 titer was an increase by 4-fold or more.

Participants who received both H1N1 vaccinations and from whom blood was collected within 14 days of the window are included. One participant was excluded due to influenza-like illness and two due to receipt of off-study vaccines. Analyses are as treated. This outcome restricts to age stratum.

Participants were provided a thermometer and a memory aid to record daily oral temperatures for 8 days (Day 0-7) after vaccination. Participants are counted as experiencing fever if they reported oral temperatures of 38 degrees Celsius or higher on any of the 8 days.

Participants who received the first vaccination and reported oral temperatures during the time period are included. Analyses are as treated.

Participants were provided a thermometer and a memory aid to record daily oral temperatures for 8 days (Day 0-7) after vaccination. Participants are counted as experiencing fever if they reported oral temperatures of 38 degrees Celsius or higher on any of the 8 days.

Participants who received the second vaccination and reported oral temperatures during the time period are included. Analyses are as treated.

Participants maintained a memory aid to record daily the occurrence of local symptoms of pain, tenderness and swelling for 8 days (Day 0-7) after vaccination based on their interference with daily activities. Participants are counted if they reported experiencing the symptom at any severity on any of the 8 days.

Participants who received the first vaccination are included. Analyses are as treated.

Participants maintained a memory aid to record daily the occurrence of local symptoms of pain, tenderness and swelling for 8 days (Day 0-7) after vaccination based on their interference with daily activities. Participants are counted if they reported experiencing the symptom at any severity on any of the 8 days.

Participants who received the second vaccination are included. Analyses are as treated.

Participants maintained a memory aid to record daily the occurrence of local reactions of redness and swelling for 8 days (Day 0-7) after vaccination. If the reaction was present, the maximum diameter was measured in millimeters (mm). Participants are counted if they were reported as experiencing the reaction with any measurement greater than 0 mm on any of the 8 days.

Participants who received the first vaccination are included. Analyses are as treated.

Participants maintained a memory aid to record daily the occurrence of local reactions of redness and swelling for 8 days (Day 0-7) after vaccination. If the reaction was present, the maximum diameter was measured in millimeters (mm). Participants are counted if they were reported as experiencing the reaction with any measurement greater than 0 mm on any of the 8 days.

Participants who received the second vaccination are included. Analyses are as treated.

Blood was collected from all participants 8 days after vaccination for testing in the HAI assay with Influenza H1N1 2009 virus as the assay antigen. Each sample was tested at least twice according to standard operating procedures and the result of each replicate reported. A participant is counted if the geometric mean of the replicate values was 1:40 or greater.

Participants who received the H1N1 vaccination and from whom blood was collected at the timepoint are included. One participant was excluded due to eligibility deviation. Analyses are as treated. This outcome restricts to age stratum.

Blood was collected from all participants 21 days after vaccination for testing in the HAI assay with Influenza H1N1 2009 virus as the assay antigen. Each sample was tested at least twice according to standard operating procedures and the result of each replicate reported. A participant is counted if the geometric mean of the replicate values was 1:40 or greater.

Participants who received the H1N1 vaccination and from whom blood was collected within 7 days of the window are included. One participant was excluded due to eligibility deviation and two due to receipt of off-study vaccines. Analyses are as treated. This outcome restricts to age stratum.

Blood was collected from all participants 8 days after vaccination for testing in the HAI assay with Influenza H1N1 2009 virus as the assay antigen. Each sample was tested at least twice according to standard operating procedures and the result of each replicate reported. A participant is counted if the geometric mean of the replicate values was 1:40 or greater.

Participants who received the H1N1 vaccination and from whom blood was collected at the timepoint are included. One participant was excluded due to influenza-like illness. Analyses are as treated. This outcome restricts to age stratum.

Blood was collected from all participants 21 days after vaccination for testing in the HAI assay with Influenza H1N1 2009 virus as the assay antigen. Each sample was tested at least twice according to standard operating procedures and the result of each replicate reported. A participant is counted if the geometric mean of the replicate values was 1:40 or greater.

Participants who received the H1N1 vaccination and from whom blood was collected within 7 days of the window are included. One participant was excluded due to influenza-like illness. Analyses are as treated. This outcome restricts to age stratum.