Safety and Immunogenicity of a Monovalent 2009 Influenza A/H1N1v Vaccine Adjuvanted With AS03A or Unadjuvanted in HIV-Infected Adults: A Randomized, Controlled Trial

Background. Human immunodeficiency virus (HIV)-infected patients have decreased immune response to vaccines. Few data are available about pandemic flu vaccination in this population. Methods. We conducted a multicenter, patient-blinded, randomized trial in a cohort of HIV-infected adults. Patients received 2 injections 21 days apart of a AS03(A)-adjuvanted H1N1v vaccine containing 3.75 mu g hemagglutinin (HA) or a nonadjuvanted H1N1v vaccine containing 15 mu g HA to assess hemagglutination inhibition (HI) response and safety. Results. A total of 309 patients were randomized, and 306 were vaccinated. After the first vaccine dose, HI titers >= 1:40 were observed in 93.4% of the patients in the adjuvanted group (A group) (n = 155) and in 75.5% in the nonadjuvanted group (B group) (n = 151) (P < .001); seroconversion rates were 88.8% and 71.2%, and factor increases in geometric mean titers (GMT) of 21.9 and 15.1, respectively. After 2 injections, 98.6% of patients of the A group and 92.1% of the B group demonstrated HI titers >= 1:40 (P = .018); seroconversion rates were 96.5% and 87.1%, respectively, and factor increases in GMT were 45.5 and 21.2, respectively. The majority of adverse events were mild to moderate in severity; no impact on CD4+ cell count or viral load has been detected. Conclusions. In HIV-1-infected adults, the AS03(A)-adjuvanted H1N1v vaccine yielded a higher immune response than did the nonadjuvanted one, with no impact on HIV infection.