TOPLINE

Recombinant zoster vaccine (RZV) induced seroconversion in more than 80% of patients with idiopathic inflammatory myopathies (IIMs) who received immunosuppressive therapies, although antibody levels remained lower than those in healthy control individuals.

METHODOLOGY

• Researchers conducted a subanalysis of a randomized, placebo-controlled, phase 4 trial in Brazil to assess the humoral immune response to RZV and the safety of the vaccine in 70 adult patients with IIM on immunosuppressive therapies and 280 healthy control individuals aged 50 years or older who received two doses of RZV administered 6 weeks apart.
• Patients were randomly assigned to receive RZV or placebo during the blinded phase, with the placebo group subsequently crossing over to receive two doses of RZV.
• Humoral response was defined as at least a fourfold increase in immunoglobulin G anti-glycoprotein E antibody levels from baseline; geometric mean titers (GMTs) and factor increase-GMTs were used for comparative analysis (60 patients with IIM were included in the immunogenicity analyses).

TAKEAWAY

• For humoral immunogenicity, seroconversion rates were lower in patients with IIM than in healthy control individuals (83.3% vs 99.3%; P < .001), with reduced postvaccination GMTs and factor increase-GMTs (P = .001 for both). Patients with IIM had reduced seroconversion compared with control individuals (adjusted odds ratio [aOR], 0.057; P < .001) and lower postvaccination GMTs (P < .001).
• The use of mycophenolate mofetil was independently associated with reduced odds of seropositivity after the second dose of RZV (aOR, 0.03; 95% CI, 0.001-0.50) and lower antibody levels (P = .022).
• A higher baseline cutaneous disease activity and a higher baseline GMT were independently associated with reduced odds of seroconversion.
• Adverse events were reported by 50.0% of patients with IIM and 72.8% of control individuals (P < .001) and were mostly mild to moderate. No vaccine-related serious adverse events were noted; disease activity was comparable between the vaccine and placebo groups, and vaccination did not induce disease flares.

IN PRACTICE

“[The study] findings suggest that both disease phenotype and treatment-related immunosuppression modulate humoral vaccine responsiveness, with direct implication for clinical decision-making,” the authors of the study wrote. “Although lower postvaccination antibody levels raise uncertainty regarding long-term protection, reduced vaccine responsiveness associated with [mycophenolate mofetil] exposure and active cutaneous disease suggests that tailored vaccination strategies may benefit selected patients,” they added.

SOURCE

The study was led by Sandra G. Pasoto, MD, PhD, Hospital das Clínicas HCFMUSP, Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brazil. It was published online on June 15, 2026, as a brief report in Arthritis Care & Research.

LIMITATIONS

The study’s short-term assessment of immunogenicity limited the evaluation of vaccine protection and durability of responses in the long term. The sample size was limited, as is inherent to a rare disease, and may have reduced the ability to detect differences in health outcomes and rare adverse events. Patients who received rituximab or cyclophosphamide were not included owing to their known profound effects on vaccine responses.

DISCLOSURES

GSK provided support for the study through an investigator-initiated grant. Additional funding was provided by the Fundacao de Amparo a Pesquisa do Estado de Sao Paulo and the Conselho Nacional de Desenvolvimento Cientifico e Tecnologico to various authors. The authors declared having no other conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.