According to a study, certain persons who take the medicine methotrexate to treat common immune system illnesses such as rheumatoid arthritis and multiple sclerosis may have a poorer immunological response to the COVID-19 vaccine.
Drugs that suppress inflammation, such as methotrexate, are commonly used to treat people with immune-mediated inflammatory illnesses. The disorders result when the immune system, meant to fight disease and drive healing, is triggered abnormally, which in turn causes inflammation, pain and swelling.
The study, published in the journal Annals of the Rheumatic Diseases, looked specifically at patients’ responses to the Pfizer-BioNTech mRNA COVID-19 vaccine, which the researchers measured by looking at the antibodies produced in each patient by the vaccine.
Once injected into the body, vaccine ingredients are supposed to cause the formation of antibodies, immunological proteins that specifically target viral proteins, rendering them inactive and marking them for removal.
However, the researchers at NYU Grossman School of Medicine and NYU Langone Health in the US cautioned that the lower antibody response in patients who take methotrexate does not necessarily mean that these patients are not protected against COVID-19.
“It is most important to state that patients should not be concerned about our study findings as the majority of patients with immune system disorders are responding well to the mRNA vaccines,” study co-first author Dr. Rebecca Haberman explained.
“It is also possible that methotrexate is delaying, rather than preventing, an adequate immune response against COVID-19,” she added.
Patients with rheumatoid arthritis who use methotrexate have a lower reaction to seasonal flu shots, according to researchers. The team wanted to determine how well these patients are protected since mRNA vaccines use a new mechanism of action that patients with these common immune disorders have not seen before.
The study enrolled healthy people and patients treated for common immune-mediated disorders, including rheumatoid arthritis, psoriatic arthritis, and psoriasis. The participants received two doses of the Pfizer-BioNTech mRNA COVID-19 vaccine.
Blood samples were analyzed to establish how many antibodies patients created after getting the vaccine. They also examined the activation of important immune system cells, such as CD8 killer T cells, which are produced as part of the immune system’s response.
Researchers’ findings
Over 90 percent of healthy people and patients using medicines other than methotrexate to manage inflammation developed robust antibody responses, according to the study. Only 62 percent of methotrexate-treated patients with immune-mediated inflammatory diseases had a satisfactory response.
Similarly, while healthy patients and those with common immune disorders who were taking anti-inflammatory drugs other than methotrexate produced CD8 T cells, patients taking methotrexate did not show an increase in CD8 T cell activation after vaccination.
“More research is needed to understand why such a significant proportion of people with common immune disorders who take methotrexate have deficiencies in mounting an antibody and cellular response. This may not necessarily mean that the vaccine is not efficacious, but that alternate vaccine strategies need to be investigated,” said study co-senior author Dr. Jose U Scher, an associate professor at NYU Langone.
He further added that other vaccine techniques could include discontinuing methotrexate at the period these individuals receive the vaccine, adjusting the drug’s dosage, or giving the vaccination a booster shot.
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