Since the outbreak of the coronavirus pandemic, we continue to learn more about the risk factors for severe COVID-19 outcomes. Studies have shown that COVID-19 does not affect all population groups equally. Generally, the risk of severe COVID-19 increases as the number of underlying medical conditions increases in a person.
Age is the strongest risk factor for severe COVID-19 outcomes. Approximately 54.1 million people aged 65 years or older reside in the United States; in 2020 this age group accounted for 81% of U.S. COVID-19 related deaths, and as of September 2021 the mortality rate in this group was more than 80 times the rate of those aged 18-29. In 2020, residents of long-term care facilities made up less than 1% of the U.S. population but accounted for more than 35% of all COVID-19 deaths. Additionally, adults of any age with certain underlying medical conditions are at increased risk for severe illness from COVID-19.
Unfortunately, studies have shown that taking certain medications strongly increases the risk for severe COVID-19 outcomes.
What is methotrexate?
Methotrexate is a medication used to treat severe psoriasis (a skin disease in which red, scaly patches form on some areas of the body) that cannot be controlled by other treatments. Methotrexate is also used along with rest, physical therapy, and sometimes other medications to treat severe active rheumatoid arthritis (RA; a condition in which the body attacks its own joints, causing pain, swelling, and loss of function) that cannot be controlled by certain other medications. Methotrexate is also used to treat certain types of cancer including cancers that begin in the tissues that form around a fertilized egg in the uterus, breast cancer, lung cancer, certain cancers of the head and neck, certain types of lymphoma, and leukemia (cancer that begins in the white blood cells). Methotrexate is sometimes given when other medicines have not been effective.
Does methotrexate reduce the risk of COVID-19 infection?
Yes, clinical and experimental data from recently conducted studies indicate that methotrexate has certain protective effects on SARS-CoV-2 infection by down-regulating angiotensin-converting enzyme (ACE)-2. Research reveals that when compared to other individuals not taken the medication, those under treatment with methotrexate, often remain virus-free when others under the same or similar condition and environment have contracted the virus.
How does methotrexate affect the body’s response to the COVID-19 vaccine?
According to a study presented to the European Congress of Clinical Microbiology & Infectious Diseases and published in Lancet Rheumatology, people taking methotrexate had low antibody responses after the first dose of the Pfizer–BioNTech mRNA COVID-19 vaccine but did show evidence of T-cell-mediated immune responses, findings from a small study show.
The common immunosuppressant has previously been linked to poor antibody responses to mRNA COVID-19 vaccines, but this appears to be the first study to look at T-cell responses in people taking methotrexate. These findings indicate that seroconversion alone might not adequately reflect vaccine immunogenicity in individuals with immune-mediated inflammatory diseases receiving therapeutic immunosuppression and caution against routine use of seroconversion data in isolation in clinical practice.
Health authorities recommend the interruption of methotrexate therapy during COVID-19 vaccination, but only in patients with stable rheumatic disease at low risk of flare, or those for whom protection from COVID-19 is of particular importance. This decision to hold methotrexate for one or two doses following each vaccination should be individualized and discussed with the treating Rheumatologist.