medwireNews: Administration of a high-dose influenza vaccine results in an improved humoral immune response when given to patients with rheumatoid arthritis (RA), suggest findings from a randomized controlled trial.
“People living with rheumatoid arthritis have an increased risk of influenza infection,” and it is therefore recommended that these patients should receive annual vaccination with an inactivated influenza vaccine, lead author Inés Colmegna (McGill University in Montreal, Québec, Canada) told delegates at the 2018 ACR/ARHP Annual Meeting in Chicago, Illinois, USA.
She added that RA patients experience suboptimal vaccine effectiveness and have a higher risk for severe influenza compared with the general population, meaning it is a “high priority to develop new approaches” to decrease influenza risk in these individuals.
A total of 279 patients with seropositive RA were randomly assigned to receive either a high-dose trivalent inactivated vaccine (60 µg hemagglutinin [HA] per strain) – previously shown to enhance influenza prevention in people aged 65 years and older – or to receive a standard-dose quadrivalent inactivated vaccine (15 µg HA per strain) in the 2016–2017 and 2017–2018 Northern Hemisphere influenza seasons.
The trivalent vaccine included the A/HongKong/4801/2014(H3N2) and B/Brisbane/60/2008 strains in both time periods, A/California/7/2009(H1N1) in 2016–2017, and A/Michigan/45/2015(H1N1) in 2017–2018. The quadrivalent vaccine included B/Phuket (B Yamagata lin) in addition to these strains.
Colmegna reported that overall responses to vaccination were “consistently higher” with the high-dose compared with the standard-dose vaccine. Rates of seroconversion, defined as a fourfold or greater increase in hemagglutination inhibition (HI) titers from baseline to 28 days post-vaccination, were significantly higher in the high-dose group for all strains, at 22.3% versus 8.6% in the standard-dose group for H3N2, 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, translating into adjusted odds ratios (ORs) of 2.93, 1.93, 2.91, and 2.79, respectively.
Similarly, rates of seroprotection – the proportion of patients with HI titers of at least 1:40 at day 28 – were significantly higher among patients in the high- versus the standard-dose group for the H3N2 strain, at 48.2% versus 30.0% (adjusted OR=2.13), but the differences did not reach statistical significance for the other strains.
Rates of adverse events (AEs) were comparable among patients in the high- and standard-dose groups, with 31.7% and 33.6%, respectively, experiencing an AE.
Myalgias were the most commonly occurring AE in both groups (33.1 vs 32.9%), followed by headaches (20.1 vs 22.9%), and tiredness (16.5 vs 23.6%). There was no evidence for worsening RA disease activity scores in the month following vaccination with either dose.
Colmegna cautioned that the trial was an “immunogenicity study not an efficacy study,” but stressed that serum HA antibodies are “considered correlates of vaccine-induced protection for inactivated influenza vaccines.”
And she believes that the findings “could change clinical practice.”
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