• Occurrence of vaccine-associated serious adverse events (SAEs) throughout the course of the study by dose level group (15 or 30 mcg), by asthma severity group (mild-to-moderate or severe), by dose level group + asthma severity group, and overall [ Time Frame: Measured at baseline and at Days 1, 8, 21, 28, 41, 80, 120, and 201 ] [ Designated as safety issue: Yes ]
  
• Occurrence of solicited local AEs within 8 days after vaccination by dose level group (15 or 30 mcg), asthma severity group (mild/moderate or severe), dose level group + asthma severity group, and overall [ Time Frame: Measured on Days 1 to 8 and 21 to 28 ] [ Designated as safety issue: Yes ]
  
• Occurrence of solicited systemic AEs within 8 days post vaccination by dose level group (15 or 30 mcg), asthma severity group (mild/moderate or severe), dose level group + asthma severity group, and overall [ Time Frame: Measured on Days 1 to 8 and 21 to 28 ] [ Designated as safety issue: Yes ]
  
• Occurrence of asthma exacerbations within 8 days post vaccination by dose level group (15 or 30 mcg), asthma severity group (mild/moderate or severe), dose level group + asthma severity group, and overall [ Time Frame: Measured on Days 1 to 8 and 21 to 28 ] [ Designated as safety issue: Yes ]
  
• Proportion of participants stratified by asthma severity achieving 4-fold or greater HAI antibody titer increases against the novel influenza H1N1 2009 virus following two administrations of Novartis H1N1 vaccine, at each dose, combined across age groups [ Time Frame: Measured on Days 1, 28, and 41 ] [ Designated as safety issue: No ]
  
• Proportion of participants stratified by asthma severity achieving a serum HAI antibody titer of 1:40 or greater against the novel influenza H1N1 2009 virus following two administrations of Novartis H1N1 vaccine at each dose, combined across age groups [ Time Frame: Measured on Days 1, 28, and 41 ] [ Designated as safety issue: No ]
  

• Proportion of participants stratified by asthma severity with a 4-fold or greater HAI antibody titer increases against the novel influenza H1N1 2009 virus following a single administration of Novartis H1N1 vaccine at each dose, combined across age groups [ Time Frame: Measured on Days 1, 8, and 21 ] [ Designated as safety issue: No ]
  
• Proportion of participants stratified by asthma severity achieving a serum HAI antibody titer of 1:40 or greater against influenza H1N1 2009 virus following a single administration of the H1N1 vaccine at each dose, combined across age groups [ Time Frame: Measured on Days 1, 8, and 21 ] [ Designated as safety issue: No ]
  

A new swine-origin influenza A/H1N1 virus was recently identified as a significant cause of respiratory illness in Mexico and the United States. In response, the World Health Organization (WHO) declared a pandemic on June 11, 2009. Current data indicates that licensed seasonal influenza vaccines are not likely to provide protection against the new H1N1 virus. Development and deployment of a vaccine for the new H1N1 virus, particularly to at-risk populations, is essential.

Groups at risk for influenza yearly include the elderly and those with asthma, and current guidelines from the Advisory Committee on Immunization Practices (ACIP) recommend vaccination of adults and children with asthma. Early, unpublished data on US patients hospitalized by H1N1 infection indicates that many had underlying asthma, and it is expected people with asthma will be on a priority list for H1N1 influenza vaccination. Data also indicate that increased dosage of vaccines may increase development of antibodies and that use of certain inhalers may affect immunization. This study will test the safety and immunogenicity of an unadjuvanted, inactivated H1N1 vaccine at two dosage levels in people with asthma.

Participation in this study will last approximately 34 weeks. Participants will be stratified into two groups: those with mild to moderate versus those with severe asthma. All participants will be randomly assigned to receive either a high dose (30 mcg) or low dose (15 mcg) H1N1 vaccine. Both vaccine dosages will be administered in two intramuscular injections 21 days apart. Participants assigned to the higher dose (30 mcg) will receive two injections of the 15 mcg vaccine at each administration.

Participants will complete study visits at entry, administration of the vaccines on Days 1 and 21, follow-ups a week after each vaccine injection, and 21 days after the second injection. Measurements at these visits will include spirometry (measurement of air entering and leaving the lungs), a questionnaire about asthma, a targeted physical examination, an adverse event and medication assessment, inspection of vaccination site, and collection of a blood sample. A urine sample will be collected for pregnancy test before each vaccination. In additions, for 8 days after each vaccination injection participants will keep a diary recording oral temperature, adverse events, asthma symptoms, and use of inhalers. These diaries will be reviewed at study visits. Participants will also receive follow-up phone calls to assess safety 60, 120, and 180 days after the last vaccine injection.