Moderna COVID-19 Vaccine Safe, Less Effective in Rheumatic Patients

Ines Colmenga, MD

Moderna COVID-19 vaccine mRNA-1273 is not associated with severe disease flares in vaccinated patients with rheumatic disease, according to late-breaking data presented at the American College of Rheumatology (ACR) 2021 Convergence this week.

The findings from a team of Canadian investigators help interpret safety outcomes, as well as the extent of limited immune response, in patients who may have been excluded from the pivotal clinical trials assessing the first emergency-authorized mRNA vaccines for the pandemic virus.

Led by Ines Colmenga, MD, Clinical Scientist at the Research Institute of the McGill University Health Care Center, investigators sought to assess the safety and immunogenicity of Moderna’s 2-dose mRNA vaccine as a full-regimen COVID-19 prophylaxis in patients with rheumatic diseases. As they noted, this is a lesser known population in COVID-19 vaccine trials—despite the understood risks rheumatic patients may face in SARS-CoV-2 infection.

“Immunocompromised conditions and/or a history of autoimmune disease were exclusion criteria of the initial SARS-CoV-2 vaccines clinical trials,” they explained.

Colmenga and colleagues conducted a non-randomized, prospective, open-label trial at 2 Quebec academic centers to observe full mRNA-1273 vaccination in patients with rheumatic disease. Their eligible patients were adults with any of the following diseases:

• Seropositive rheumatoid arthritis on stable treatment for ≥3 months
• Systemic lupus erythematosus (SLE) on stable mycophenolate mofetil (MMF) treatment
• Rheumatic diseases treated with ≥10 mg prednisone

Control patients without rheumatic disease were matched by age and sex with the trial population. Investigators sought a primary outcome of solicited local and systemic reactogenicity adverse events in 7 days following each COVID-19 vaccine dose, as well as unsolicited adverse events including disease flares in 28 days following each dose.

The trial’s secondary outcome was the effects of age and treatment on seropositivity, per presence of serum immunoglobulin G (IgG) antibody against the SARS-CoV-2 spike protein and its receptor binding domain. Investigators measured for such antibodies at baseline and within 28 days of each dose via an ELISA platform.

The trial population included 220 participants; 131 had rheumatoid arthritis, 23 had SLE, 8 had another rheumatic disease, and 58 served as controls. Mean patient age was 60.4 years old; nearly three-fourths (72%) of patients were female.

Investigators observed a greater rate of local and systemic solicited adverse events following the second vaccine dose, versus the first dose, in all subjects (94% vs 86.8%; 7.2%; 95% CI, 2.8 – 11.7). The most commonly reported solicited event was injection site pain. Swollen joints were more frequent in patients with rheumatoid arthritis than in controls following both vaccine doses (22.9% vs 3.4%; 19.5%; 95% CI, 10.9 – 28.0). There was no observed significant increase in rheumatic disease activity scores following vaccination, however.

Seropositivity for both IgG antibody versus the spike protein and its receptor-binding domain were 100% in controls after their first dose; only 67.7% of rheumatoid arthritis patients, 34.8% of SLE patients, and 87.5% of rheumatic disease patients incurred such antibodies. Following the second dose, those rates increased to 88.5%, 78.3%, and 87.5%, respectively.

Colmenga and colleagues observed a similar second-dose seropositivity among older (age ≥65) and younger patients with rheumatoid arthritis (88% vs 88.8%). Patients taking rituximab had significantly lower post-full vaccination seropositivity (9% vs 88%) than patients not on the drug, as did patients on MMF (39% vs 58%).

“In this prospective study, the mRNA-1273 SARS-CoV-2 vaccine was not associated with severe disease flares,” they concluded. “MMF and rituximab were associated with a reduction in vaccine-induced humoral responses.”

The study, "COVID-19 Vaccine in Immunosuppressed Adults with Autoimmune Diseases," was presented at ACR 2021.