1 week off methotrexate works okay for RA patients receiving flu shot

Temporarily discontinuing methotrexate treatment for 1 week appears to induce satisfactory response to a seasonal influenza vaccine in patients with rheumatoid arthritis (RA), with a similar effect as a 2-week interruption schedule, according to a study.

The study included RA patients on a stable dose of methotrexate who are scheduled to receive the quadrivalent 2021–2022 seasonal influenza vaccine containing H1N1, H3N2, B-Yamagata, and B-Victoria strains. They were randomly assigned to groups that held methotrexate for 1 week (n=90) or 2 weeks (n=88) after receiving the flu shot.

The mean methotrexate dose in the 1-week-hold and the 2-week-hold groups were similar at 12.6 and 12.9 mg/week, respectively. The two groups were also similar in terms of baseline demographics and disease characteristics, including age, gender, seropositivity for rheumatoid factor (RF) or anticyclic citrullinated peptide antibody (ACPA), or disease activity score (DAS) 28 using C-reactive protein (CRP).

The primary outcome of the proportion of patients with a satisfactory flu vaccine response was comparable in the 1-week-hold and the 2-week-hold groups (68.9 percent vs 75.0 percent, respectively; p=0.364). Satisfactory response was defined as ≥4-fold increase in hemagglutination inhibition antibody titres against two or more of the four vaccine strains 4 weeks after vaccination.

Finally, there were no significant between-group differences in the seroprotection rate and the fold-increase in antibody titres to each of the four influenza antigens.

The flu vaccine was well tolerated, and none of the patients developed serious adverse events related to the vaccination during the follow-up period.

The findings have important clinical implications, since minimizing the methotrexate discontinuation period is critical when a vaccination protocol, such as those for COVID-19 and hepatitis, requires multiple doses. Repeated discontinuation for 2 weeks or longer during a vaccination series of two doses given 3–4 weeks apart can increase the risk of a disease flare.