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Immunogenicity and safety of AS03-adjuvanted 2009 influenza A H1N1 vaccine in children 6–35 months

2010; Elsevier BV; Volume: 28; Issue: 36 Linguagem: Inglês

10.1016/j.vaccine.2010.06.065

1873-2518

Alfonso Carmona, Félix Omeñaca, Juan Carlos Tejedor Torres, José Merino, Tejaswini Vaman, Ilse Dieussaert, Paul Gillard, Javier Arı́stegui,

Respiratory viral infections research

We report on the evaluation of the immunogenicity and reactogenicity/safety of AS03-adjuvanted vaccine against pandemic influenza A/H1N1/2009 in young children. In this open-label, randomized study, 157 healthy children aged 6–35 months received two doses (21 days apart) of split-virion inactivated A/California/7/2009 H1N1 vaccine containing either (i) 1.9 μg hemagglutinin (HA) and AS03B (5.93 mg tocopherol) (N = 104) or (ii) 3.75 μg HA and AS03A (11.86 mg tocopherol) (N = 53). At 21 days following the first dose of AS03B-adjuvanted vaccine (1.9 μg HA) the percentage of children with hemagglutination-inhibition titers of ≥40 against the vaccine strain rose from 3.0% before vaccination to 100%. The seroconversion rate was 99% and the geometric mean titer (GMT) increased from 6 to 313. After the second dose the GMT increased further to 2008. The higher dose AS03A-adjuvanted 3.75 μg HA vaccine did not further increase the immune response. Solicited symptoms reported within 7 days following vaccination were mainly mild to moderate. After the first dose of AS03B-adjuvanted vaccine (1.9 μg HA) the most common solicited symptoms were pain at the injection site (35.6%) and irritability (31.7%). Fever (axillary ≥37.5 °C) was reported with an incidence of 20.2%. After the second dose reactogenicity tended to increase (injection site pain: 41.3%; irritability: 46.2%; fever ≥37.5 °C: 67.3%). Spontaneously reported adverse events with an intensity that prevented normal activities were documented for 2.9–6.7% of doses with only one event (vomiting) considered related to vaccination. There was one serious adverse event reported in the AS03A-adjuvanted 3.75 μg HA vaccine group (traumatic brain injury) which was not considered as related to vaccination. In conclusion, these data suggest that a first dose of AS03B-adjuvanted A/H1N1/2009 vaccine containing 1.9 μg HA in children 6–35 months old is highly immunogenic and that the overall reactogenicity profile is acceptable although reactions including fever tend to increase after a second dose.