Bruno Granwehr, MD, MS
What is the immunogenicity and safety of 2 different doses of a monovalent, unadjuvanted influenza A (H1N1) 2009 vaccine?
Ongoing randomized controlled trial. ClinicalTrials.gov NCT00938639.
Blinded (participants, clinicians).*
Single center in Adelaide, South Australia, Australia.
240 healthy adults 18 to 64 years of age (mean age 44 y, 56% women). Exclusion criteria were pregnancy, confirmed or suspected 2009 H1N1 infection, or receipt of an experimental influenza vaccine in the past 6 months.
Single doses of a 15-µg (n = 120) or 30-µg (n = 120) monovalent, unadjuvanted, inactivated, split-virus 2009 (H1N1) vaccine (hemagglutinin antigen) given by intramuscular injection.
Proportion of persons with antibody titers ≥ 1:40 on hemagglutination-inhibition (HI) assay, proportion with seroconversion or significant increase in antibody titer, factor increase in geometric mean titer (GMT), and adverse events. This study reports outcomes after the first of 2 planned vaccine doses.
33% of persons in the 15-µg group and 30% in the 30-µg group had HI antibody titers ≥ 1:40 before vaccination. At 21 days, > 90% of persons in both vaccine groups had HI antibody titers ≥ 1:40, and > 70% had seroconversion or significant titer increases (Table). GMTs ranged from 217 to 304 (Table); GMT factor increases were 11 (95% CI 8 to 14) in the 15-µg group and 19 (CI 14 to 26) in the 30-µg group (P = not significant). No deaths or serious adverse events were reported.
In healthy adults, a 15-µg dose of unadjuvanted influenza (H1N1) 2009 vaccine was immunogenic within 21 days.
15-µg or 30-µg single-dose unadjuvanted influenza A (H1N1) 2009 vaccine in healthy adults†
†HI = hemagglutination-inhibition; other abbreviations defined in Glossary.
Granwehr B. A 15-µg dose of unadjuvanted influenza A (H1N1) 2009 vaccine was immunogenic in healthy adults within 21 days. Ann Intern Med. ;152:JC1–9. doi: 10.7326/0003-4819-152-2-201001190-02009
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Published: Ann Intern Med. 2010;152(2):JC1-9.
Infectious Disease, Influenza, Prevention/Screening, Vaccines/Immunization.
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