People taking methotrexate—commonly used by patients with rheumatoid arthritis, psoriasis and other autoimmune diseases—may not have a full immune response to mRNA vaccines, according to new research published Tuesday in the journal Annals of Rheumatic Diseases.
The researchers, from New York University Langone Health and FAU Erlangen-Nuremberg and Universitätsklinikum Erlangen in Germany, looked at patients with immune-mediated inflammatory diseases (IMIDs), some taking methotrexate and others who weren’t. They also looked at healthy control participants. All were vaccinated with BNT 162b2, Pfizer/BioNTech’s Covid-19 mRNA vaccine, and assessed at baseline and after receiving their second shot.
In both the New York and German cohort, lower numbers of people taking methotrexate achieved adequate immune responses than those who were not taking it and those who were healthy.
The researchers found that 28 of 45 (62.2%) receiving methotrexate achieved adequate immunogenicity compared to 204 of 208 (98.1%) of healthy controls and 34 of 37 (91.9%) patients with IMID not taking methotrexate.
It is noted that in both New York and Germany, patients who were taking methotrexate were older on average than IMID patients who were not taking it and control patients.
The research also notes that certain essential T-cells needed for fighting off infection were induced in healthy adults and IMID patients not taking methotrexate but were not induced in those who were on the medication.
The authors say that the research does have some limitations. These include a small sample size, the fact that they only tested the Pfizer/BioNTech mRNA vaccine and that they did not include participants who had previous asymptomatic Covid-19 infections.
The authors say that the results suggest further study is needed into how to optimally protect IMID patients against Covid-19.