RA patients experience enhanced immune response with high-dose influenza vaccine
medwireNews: Findings from a randomised controlled trial suggest that rheumatoid arthritis (RA) patients who are given a high-dose influenza vaccine experience a stronger immune response than those given a standard dose.
Inés Colmegna (McGill University in Montreal, Québec, Canada), who presented the results at the 2018 ACR/ARHP Annual Meeting in Chicago, Illinois, USA, explained that RA patients have a 22% increased risk of influenza and an 82% increased risk of influenza-related complications compared with non-RA individuals.
She said that although influenza vaccination is recommended for all RA patients, they experience suboptimal vaccine effectiveness, and therefore interventions are needed to improve vaccine immunogenicity in this population.
The investigators randomly assigned 279 seropositive RA patients aged an average of 61 years to receive either a high-dose trivalent (60 μg of haemagglutinin [HA] per strain) or a standard-dose quadrivalent (15 μg HA per strain) inactivated influenza vaccine during the 2016–2017 and 2017–2018 Northern Hemisphere influenza seasons. The A/HongKong/4801/2014 (H3N2) and B/Brisbane/60/2008 vaccine strains were given in both seasons, while the A/California/7/2009 (H1N1) strain was given in 2016–2017 only, and A/Michigan/45/2015 (H1N1) in the later period only. The quadrivalent vaccine also included the B/Phuket (B Yamagata lin) strain.
At 28 days after vaccination, response rates were “consistently higher” among the 139 participants who received the high-dose vaccine compared with the 140 who were given the standard dose, reported Colmegna.
Indeed, rates of seroconversion, defined as at least a fourfold increase in serum HA inhibition (HI) titres from baseline to day 28, were 22.3% versus 8.6% for the H3N2 strain, 44.6% versus 28.6% for B/Brisbane, 51.4% versus 25.3% for A/California H1N1 and 46.4% versus 24.6% for A/Michigan H1N1. The corresponding odds ratios (ORs) were 2.93, 1.93, 2.91 and 2.79 after adjustment for factors including age and RA disease duration.
And the proportion of patients with seroprotection – HI titres of at least 1:40 at day 28 – was also significantly higher among those given the high-dose versus the standard-dose vaccine for the H3N2 strain, with rates of 48.2% versus 30.0%. The difference in seroprotection rates did not reach statistical significance for the other strains, however.
Colmegna said that a comparable proportion of patients in the high-dose and standard-dose groups experienced adverse events (31.7 vs 33.6%), most commonly myalgias (33.1 vs 32.9%), headaches (20.1 vs 22.9%) and tiredness (16.5 vs 23.6%). She emphasised that RA disease activity did not worsen in the month following vaccination for either dose group.
“This is the first [randomised controlled trial] documenting a successful intervention to enhance influenza vaccine responses in patients with rheumatoid arthritis”, concluded Colmegna.
She cautioned, however, that “this is an immunogenicity study and not an efficacy study”.
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