Swine Flu and Immune-Suppressing Drugs

Many medications prescribed for rheumatoid arthritis can weaken the immune system, including prednisone, methotrexate, and, of course, the biologic agents such as Humira, Enbrel and Remicade, to name but a few.  The use of these medications can make a patient more susceptible to the H1N1 virus (the so-called swine flu) and the regular seasonal influenza.  And if a patient on an immunosuppressive drug does contract such a viral illness, there is a much higher risk of developing more severe-and thus more life-threatening-disease.

The key is to avoid contracting seasonal influenza or the swine flu H1N1 virus.  This can be best achieved through frequent hand washing, having those around you cover their mouths when they cough or sneeze, and avoiding individuals known to be ill, including family members or acquaintances in social gatherings.  The H1N1 virus spreads mainly from person to person through coughing or sneezing by people with the virus.  However, individuals can also be infected by touching objects contaminated with the virus, and then in turn touching her mouth or nose.  Therefore, try also to get out of the habit of touching your mouth or nose this season.

A recent article in The Lancet Infectious Diseases journal examined how influenza affects immunosuppressed individuals with HIV/AIDS or cancer, transplant patients and patients on dialysis or steroids.  Rheumatoid arthritis patients per se were not studied, but it is my opinion that the conclusions can be extrapolated to those rheumatoid arthritis patients taking immunosuppressive medications.

The article found that there is little research on using vaccination to prevent influenza in immunosuppressed people.  Studies of HIV/AIDS patients show a lower antibody response to vaccination, but studies also show that vaccination results in fewer and less severe cases of flu in these patients.  Larger studies are needed to know how useful vaccination is for these patients.

Transplant patients have higher flu infection rates due to the immunosuppressant drugs they take to prevent rejection of the transplanted organ.  Cancer patients on chemotherapy also experience significant immunosuppression, the data showing that up to 33% of these patients contract flu.  Patients taking cor€ticosteroids such as prednisone appear to have a positive response to flu vaccination.

The authors of this paper conclude that most immunosuppressed populations have a greater risk of influenza-associated complications.  These patients may have an impaired antibody response to vaccination, thus rendering the vaccine less protective:  One study found that patients on cancer chemotherapy had a poor antibody response to vaccination, whereas dialysis patients and transplant patients achieved fairly good antibody responses when vaccinated.

While most immunosuppressed patients can be safely vaccinated, it is not known whether all will develop significant immunity to ward off swine flu or traditional influenza.  Rheumatoid arthritis patients in particular have not been well-studied.