Two doses of inactivated influenza H1N1 vaccine, 15 mcg per dose, administered as a single 0.5 milliliters (mL) intramuscular injection in the deltoid muscle.

Normal saline (placebo control) administered as a single 0.5 mL intramuscular injection in the deltoid muscle.

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. Day 21 post first H1N1 vaccination is Study Day 42 for Group 4, and is Study Day 21 for all other groups.

Participants maintained a memory aid to record daily the occurrence of systemic symptoms of feverishness, malaise, myalgia, headache, and nausea 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 maintained a memory aid to record daily the occurrence of systemic symptoms of feverishness, malaise, myalgia, headache, and nausea 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 maintained a memory aid to record daily the occurrence of systemic symptoms of feverishness, malaise, myalgia, headache, and nausea 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 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 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 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 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. First H1N1 vaccination was given on Study Day 0 for Groups 1, 2 and 3, and on Study Day 21 for Group 4.

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. Second H1N1 vaccination was given on Study Day 21 for Groups 1, 2 and 3, and on Study Day 42 for Group 4.

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. The TIV vaccination was given on Study Day 42 for Group 1, Study Day 0 for Groups 2 and 4, and on Study Day 21 for Group 3.

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. The first placebo vaccination was given on Study Day 0 for Groups 1, 3 and 4, and on Study Day 21 for Group 2.

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. The second placebo vaccination was given on Study Day 21 for Groups 1 and 4, on Study Day 42 for Groups 2 and 3.

Participants maintained a memory aid to record daily the occurrence of local reactions of swelling and redness 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 maintained a memory aid to record daily the occurrence of local reactions of swelling and redness 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 maintained a memory aid to record daily the occurrence of local reactions of swelling and redness 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 maintained a memory aid to record daily the occurrence of local reactions of swelling and redness 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 maintained a memory aid to record daily the occurrence of local reactions of swelling and redness 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.

Blood was collected from participants for testing in the HAI assay against each strain in the 2009-2010 trivalent influenza vaccine. 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 63 titer was 1:40 or greater, or the Day 0 titer was greater than or equal to 1:10 and the Day 63 titer was an increase by 4-fold or more.

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. Day 21 post second H1N1 vaccination is Study Day 63 for Group 4, and is Study Day 42 for all other groups.

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. Day 21 post second H1N1 vaccination is Study Day 63 for Group 4, and is Study Day 42 for all other groups.

Blood was collected from participants 21 days after the last vaccination for testing in the HAI assay against each strain in the 2009-2010 trivalent influenza vaccine. Each sample was tested according to standard operating procedures. A participant is counted if the value at the Day 63 timepoint was 1:40 or greater.

Blood was collected from participants 21 days after the last vaccination for testing in the HAI assay against each strain in the 2009-2010 trivalent influenza vaccine. Each sample was tested according to standard operating procedures. A participant is counted if the value at the Day 63 timepoint was 1:40 or greater.

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. For Group 4, this timepoint is Study Day 63, all others it is Study Day 42. 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.

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. For Group 4, this timepoint is Study Day 63, all others it is Study Day 42. 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 received 15 mcg H1N1 Vaccine + saline placebo on Day 0; 15 mcg H1N1 Vaccine + Trivalent Influenza Vaccine (TIV) on Day 21, and saline placebo on Day 42

Participants received 15 mcg H1N1 Vaccine + saline placebo on Day 0; 15 mcg H1N1 Vaccine + saline placebo on Day 21, and Trivalent Influenza Vaccine (TIV) on Day 42

Total of all reporting groups

Participants received 15 mcg H1N1 Vaccine + Trivalent Influenza Vaccine (TIV) on Day 0; 15 mcg H1N1 Vaccine + saline placebo on Day 21, and saline placebo on Day 42

Participants received 15 mcg H1N1 Vaccine + saline placebo on Day 0; 15 mcg H1N1 Vaccine + Trivalent Influenza Vaccine (TIV) on Day 21, and saline placebo on Day 42

Participants received 15 mcg H1N1 Vaccine + saline placebo on Day 0; 15 mcg H1N1 Vaccine + saline placebo on Day 21, and Trivalent Influenza Vaccine (TIV) on Day 42

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. For Group 4, this timepoint is Study Day 42, all others it is Study Day 21. 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, both within 4 days of the window, are included. One participant was excluded due to receipt of a non-study vaccine. 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 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. Day 21 post first H1N1 vaccination is Study Day 42 for Group 4, and is Study Day 21 for all other groups.

Participants who received the H1N1 vaccination and from whom blood was collected at the timepoint, both within 4 days of the window, are included. Seven participants were excluded due to eligibility deviations, vaccine administration error or other protocol deviations. Analyses are as treated. This outcome restricts to age stratum.

Blood was collected from participants for testing in the HAI assay against each strain in the 2009-2010 trivalent influenza vaccine. 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 63 titer was 1:40 or greater, or the Day 0 titer was greater than or equal to 1:10 and the Day 63 titer was an increase by 4-fold or more.

Participants who received all vaccinations and from whom blood was collected at the timepoint, all within 4 days of the window, are included. Eight participants were excluded due to eligibility deviations, vaccine administration error or other protocol deviations. Analyses are as treated. This outcome restricts to age stratum.

Blood was collected from participants for testing in the HAI assay against each strain in the 2009-2010 trivalent influenza vaccine. 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 63 titer was 1:40 or greater, or the Day 0 titer was greater than or equal to 1:10 and the Day 63 titer was an increase by 4-fold or more.

Participants who received all vaccinations and from whom blood was collected at the timepoint, all within 4 days of the window, are included. Three participants were excluded due to receipt of non-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 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. Day 21 post second H1N1 vaccination is Study Day 63 for Group 4, and is Study Day 42 for all other groups.

Participants who received both H1N1 vaccinations and from whom blood was collected at the timepoint, all within 4 days of the window, are included. Eight participants were excluded due to eligibility deviations, vaccine administration error or other protocol deviations. 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. Day 21 post second H1N1 vaccination is Study Day 63 for Group 4, and is Study Day 42 for all other groups.

Participants who received both H1N1 vaccinations and from whom blood was collected at the timepoint, all within 4 days of the window, are included. Three participants were excluded due to receipt of non-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 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. Day 21 post first H1N1 vaccination is Study Day 42 for Group 4, and is Study Day 21 for all other groups.

Participants who received the H1N1 vaccination and from whom blood was collected at the timepoint are included. One participant was excluded due to receipt of a non-study vaccine. Analyses are as treated. This outcome restricts to age stratum.

Participants maintained a memory aid to record daily the occurrence of systemic symptoms of feverishness, malaise, myalgia, headache, and nausea 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.

Blood was collected from participants 21 days after the last vaccination for testing in the HAI assay against each strain in the 2009-2010 trivalent influenza vaccine. Each sample was tested according to standard operating procedures. A participant is counted if the value at the Day 63 timepoint was 1:40 or greater.

Participants who received all scheduled vaccinations and from whom blood was collected at the timepoint, all within 4 days of the window, are included. Eight participants were excluded due to eligibility deviations, vaccine administration error or other protocol deviations. Analyses are as treated. This outcome restricts to age stratum.

Blood was collected from participants 21 days after the last vaccination for testing in the HAI assay against each strain in the 2009-2010 trivalent influenza vaccine. Each sample was tested according to standard operating procedures. A participant is counted if the value at the Day 63 timepoint was 1:40 or greater.

Participants who received all scheduled vaccinations and from whom blood was collected at the timepoint, all within 4 days of the window, are included. Three participants were excluded due to receipt of non-study vaccines. 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. For Group 4, this timepoint is Study Day 63, all others it is Study Day 42. 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 at the timepoint, all within 4 days of the window, are included. Eight participants were excluded due to eligibility deviations, vaccine administration error or other protocol deviations. 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. For Group 4, this timepoint is Study Day 63, all others it is Study Day 42. 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 at the timepoint, all within 4 days of the window, are included. Three participants were excluded due to receipt of non-study vaccines. Analyses are as treated. This outcome restricts to age stratum.

Participants maintained a memory aid to record daily the occurrence of systemic symptoms of feverishness, malaise, myalgia, headache, and nausea 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 systemic symptoms of feverishness, malaise, myalgia, headache, and nausea 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 third vaccination 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 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 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 third 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. First H1N1 vaccination was given on Study Day 0 for Groups 1, 2 and 3, and on Study Day 21 for Group 4.

Participants who received the first H1N1 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. Second H1N1 vaccination was given on Study Day 21 for Groups 1, 2 and 3, and on Study Day 42 for Group 4.

Participants who received the second H1N1 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. The TIV vaccination was given on Study Day 42 for Group 1, Study Day 0 for Groups 2 and 4, and on Study Day 21 for Group 3.

Participants who received the TIV 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. The first placebo vaccination was given on Study Day 0 for Groups 1, 3 and 4, and on Study Day 21 for Group 2.

Participants who received the first placebo 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. The second placebo vaccination was given on Study Day 21 for Groups 1 and 4, on Study Day 42 for Groups 2 and 3.

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

Participants maintained a memory aid to record daily the occurrence of local reactions of swelling and redness 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 H1N1 vaccination are included. Analyses are as treated.

Participants maintained a memory aid to record daily the occurrence of local reactions of swelling and redness 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 H1N1 vaccination are included. Analyses are as treated.

Participants maintained a memory aid to record daily the occurrence of local reactions of swelling and redness 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 TIV vaccination are included. Analyses are as treated.

Participants maintained a memory aid to record daily the occurrence of local reactions of swelling and redness 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 placebo vaccination are included. Analyses are as treated.

Participants maintained a memory aid to record daily the occurrence of local reactions of swelling and redness 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 placebo vaccination are included. Analyses are as treated.

Participants received 15 mcg H1N1 Vaccine + Trivalent Influenza Vaccine (TIV) on Day 0; 15 mcg H1N1 Vaccine + saline placebo on Day 21, and saline placebo on Day 42

Participants received 15 mcg H1N1 Vaccine + saline placebo on Day 0; 15 mcg H1N1 Vaccine + Trivalent Influenza Vaccine (TIV) on Day 21, and saline placebo on Day 42

Participants received 15 mcg H1N1 Vaccine + saline placebo on Day 0; 15 mcg H1N1 Vaccine + saline placebo on Day 21, and Trivalent Influenza Vaccine (TIV) on Day 42