title: H1N1 influenza A outbreak among young medical staff members who received single dose of non-adjuvanted split-virion 2009 H1N1 vaccine.
abstract: We experienced an H1N1 influenza A outbreak among medical staff members who had received a vaccination. To investigate the preventive effects of the H1N1 influenza vaccine on the H1N1 influenza A infection, we examined the data on the medical staff members and patients with confirmed H1N1 influenza A or influenza-like illness retrospectively. Approximately half of the young individuals under 30 years of age developed H1N1 influenza A, while the diagnosis was established in 3% of medical staff over the age of 30 and 0.9% of patients with a median age of 67. The mechanism for association between age and the risk of H1N1 infection is unclear; however, it might have been associated with an age-related increase in the prevalence of neutralizing antibody titers against the 2009 H1N1 influenza A as indicated by previous reports. This study showed that current Japanese H1N1 influenza A vaccine program using one dose of non-adjuvant split-virion 2009 H1N1 vaccine with 7.5 μg hemagglutinin had a limited preventive effect on H1N1 influenza A infection in adults under 30 years of age.
authors.affiliation: Department of Nephrology, Kameda Medical Center, Kamogawa, Japan. mami.ohara.kameda@gmail.com
authors.forename: Mamiko
authors.initials: M
authors.lastname: Ohara
authors.forename: Masaharu
authors.initials: M
authors.lastname: Tsubokura
authors.forename: Hosokawa
authors.initials: H
authors.lastname: Naoto
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kami
authors.forename: Takahiro
authors.initials: T
authors.lastname: Mochizuki
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D057134:Antibodies, Neutralizing / Q000097:blood; D000914:Antibodies, Viral / Q000097:blood; D004196:Disease Outbreaks; D005260:Female; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology*; D007252:Influenza Vaccines / Q000008:administration & dosage / Q000276:immunology*; D007251:Influenza, Human / Q000453:epidemiology*; D008297:Male; D008503:Medical Staff; D008875:Middle Aged; D012189:Retrospective Studies; D015164:Vaccines, Inactivated / Q000008:administration & dosage / Q000276:immunology; D022223:Vaccines, Subunit / Q000008:administration & dosage / Q000276:immunology
chemical_list: D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D007252:Influenza Vaccines; D015164:Vaccines, Inactivated; D022223:Vaccines, Subunit