Trial of 2009 influenza A (H1N1) monovalent MF59-adjuvanted vaccine

N Engl J Med. 2009 Dec 17;361(25):2424-35. doi: 10.1056/NEJMoa0907650. Epub 2009 Sep 10.


Background: The 2009 pandemic influenza A (H1N1) virus has emerged to cause the first pandemic of the 21st century. Development of effective vaccines is a public health priority.

Methods: We conducted a single-center study, involving 176 adults, 18 to 50 years of age, to test the monovalent influenza A/California/2009 (H1N1) surface-antigen vaccine, in both MF59-adjuvanted and nonadjuvanted forms. Subjects were randomly assigned to receive two intramuscular injections of vaccine containing 7.5 microg of hemagglutinin on day 0 in each arm or one injection on day 0 and the other on day 7, 14, or 21; or two 3.75-microg doses of MF59-adjuvanted vaccine, or 7.5 or 15 microg of nonadjuvanted vaccine, administered 21 days apart. Antibody responses were measured by means of hemagglutination-inhibition assay and a microneutralization assay on days 0, 14, 21, and 42 after injection of the first dose.

Results: The most frequent local and systemic reactions were pain at the injection site and muscle aches, noted in 70% and 42% of subjects, respectively; reactions were more common with the MF59-adjuvanted vaccine than with nonadjuvanted vaccine. Three subjects reported fever, with a temperature of 38 degrees C or higher, after either dose. Antibody titers, expressed as geometric means, were higher at day 21 among subjects who had received one dose of MF59-adjuvanted vaccine than among those who had received one dose of nonadjuvanted vaccine (P<0.001 by the microneutralization assay). By day 21, hemagglutination-inhibition and microneutralization antibody titers of 1:40 or more were seen in 77 to 96% and 92 to 100% of subjects receiving MF59-adjuvanted vaccine, respectively, and in 63 to 72% and 67 to 76% of those receiving nonadjuvanted vaccine, respectively. By day 42, after two doses of vaccine, hemagglutination-inhibition and microneutralization antibody titers of 1:40 or more were seen in 92 to 100% and 100% of recipients of MF59-adjuvanted vaccine, respectively, and in 74 to 79% and 78 to 83% of recipients of nonadjuvanted vaccine, respectively.

Conclusions: Monovalent 2009 influenza A (H1N1) MF59-adjuvanted vaccine generates antibody responses likely to be associated with protection after a single dose is administered. ( number, NCT00943358).

Publication types

  • Clinical Trial, Phase I
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adjuvants, Immunologic / administration & dosage*
  • Adjuvants, Immunologic / adverse effects
  • Adolescent
  • Adult
  • Antibodies, Viral / blood*
  • Female
  • Hemagglutination Inhibition Tests
  • Hemagglutinins, Viral / immunology
  • Humans
  • Influenza A Virus, H1N1 Subtype / immunology*
  • Influenza Vaccines / administration & dosage
  • Influenza Vaccines / adverse effects
  • Influenza Vaccines / immunology*
  • Influenza, Human / immunology*
  • Influenza, Human / prevention & control
  • Injections, Intramuscular
  • Male
  • Middle Aged
  • Neutralization Tests
  • Polysorbates / administration & dosage
  • Polysorbates / adverse effects
  • Squalene / administration & dosage
  • Squalene / adverse effects
  • Squalene / immunology
  • Young Adult


  • Adjuvants, Immunologic
  • Antibodies, Viral
  • Hemagglutinins, Viral
  • Influenza Vaccines
  • MF59 oil emulsion
  • Polysorbates
  • Squalene

Associated data