Adjuvanted vs Non-Adjuvanted Flu Vaccine: Which Is Better for Young Children?
The MF59-adjuvanted, quadrivalent, inactivated influenza vaccine (aIIV4) may provide better protection from influenza virus than non-adjuvanted influenza vaccines in young children aged 6 to 23 months, according to new findings.
Researchers arrived at this conclusion following a study of 10,644 children aged 6 months to 5 years over the course of 2 influenza seasons.
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Participants were randomly assigned to receive either aIIV4 or a non-adjuvanted inactivated influenza vaccine—such as trivalent inactivated influenza vaccine (IIV3) or quadrivalent inactivated influenza vaccine (IIV4).
Vaccine-naïve participants received 2 doses of the study vaccine on days 1 and 29 of the study, and non-vaccine-naïve participants received only 1 dose on day 1. Children aged 6 to 35 months received one or two 0.25 mL doses of the vaccine, and children aged 3 to 5 years received one or two 0.5 mL doses.
A total of 10,612 participants were vaccinated with aIIV4 (n = 5338) or the comparator vaccine (n = 5274). Results of the study revealed that relative vaccine efficacy was similar between groups for the overall study population (relative vaccine efficacy -0.67).
However, relative vaccine efficacy was found to be significantly greater for aIIV4 than for the comparator vaccine (relative vaccine efficacy 31.37) specifically among children aged 6 to 23 months.
Furthermore, in children aged 6 months to 5 years, superior immunogenic response was observed for all 4 vaccine strains (geometric mean titer ratios: 1.91 for A/H1N1; 1.71 for A/H3N2, 2.19 for B/Yamagata; and 2.12 for B/Victoria) and 3 heterologous strains (1.94 for A/H3N2; 2.17 for B/Yamagata; and 2.12 for B/Victoria).
The researchers noted that, although safety profiles were similar, more frequent solicited adverse events occurred in the aIIV4 group than in the comparator group (73% vs 64%).
“Although there was no additional benefit of aIIV4 compared with the US-licensed non-adjuvanted influenza vaccines in the overall study population, in the youngest and most vulnerable population of children in this trial, aIIV4 provided greater protection against influenza than a non-adjuvanted vaccine when assessed in this prespecified age group of 6 through 23 months,” the researchers wrote.
“Additional clinical benefit was also apparent early after first vaccination in vaccine-naive participants aged 6 months through 5 years,” they added.
—Christina Vogt
Reference:
Vesikari T, Kirstein J, Go GD, et al. Efficacy, immunogenicity, and safety evaluation of an MF59-adjuvanted quadrivalent influenza virus vaccine compared with non-adjuvanted influenza vaccine in children: a multicenter, randomized controlled, observer-blinded, phase 3 trial. Lancet Respir Med. 2018;6(5):345-356. https://doi.org/10.1016/S2213-2600(18)30108-5