PLoS ONE (Jan 2012)

Immunogenicity and tolerability after two doses of non-adjuvanted, whole-virion pandemic influenza A (H1N1) vaccine in HIV-infected individuals.

  • Heimo Lagler,
  • Katharina Grabmeier-Pfistershammer,
  • Veronique Touzeau-Römer,
  • Selma Tobudic,
  • Michael Ramharter,
  • Judith Wenisch,
  • Guido Andrés Gualdoni,
  • Monika Redlberger-Fritz,
  • Theresia Popow-Kraupp,
  • Armin Rieger,
  • Heinz Burgmann

DOI
https://doi.org/10.1371/journal.pone.0036773
Journal volume & issue
Vol. 7, no. 5
p. e36773

Abstract

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BackgroundDuring the influenza pandemic of 2009/10, the whole-virion, Vero-cell-derived, inactivated, pandemic influenza A (H1N1) vaccine Celvapan® (Baxter) was used in Austria. Celvapan® is adjuvant-free and was the only such vaccine at that time in Europe. The objective of this observational, non-interventional, prospective single-center study was to evaluate the immunogenicity and tolerability of two intramuscular doses of this novel vaccine in HIV-positive individuals.Methods and findingsA standard hemagglutination inhibition (HAI) assay was used for evaluation of the seroconversion rate and seroprotection against the pandemic H1N1 strain. In addition, H1N1-specific IgG antibodies were measured using a recently developed ELISA and compared with the HAI results. Tolerability of vaccination was evaluated up to one month after the second dose. A total of 79 HIV-infected adults with an indication for H1N1 vaccination were evaluated. At baseline, 55 of the 79 participants had an HAI titer ≥1:40 and two patients showed a positive IgG ELISA. The seroconversion rate was 31% after the first vaccination, increasing to 41% after the second; the corresponding seroprotection rates were 92% and 83% respectively. ELISA IgG levels were positive in 25% after the first vaccination and in 37% after the second. Among the participants with baseline HAI titers 60 years of age had a baseline HAI titer ConclusionThe non-adjuvanted pandemic influenza A (H1N1) vaccine was well tolerated and induced a measurable immune response in a sample of HIV-infected individuals.