Flu vaccine's effects reduced in arthritis patients treated with rituximab

Flu shots do not protect arthritis patients who are being treated with the intravenous drug rituximab, according to a new study by Dutch researchers, The New York Times and Los Angeles Times reported Jan. 7.

Rheumatoid arthritis, which affects more than 4.6 million people worldwide, is an autoimmune disease that attacks the patient's joints and surrounding tissues. It also compromises a patient's immune system, leaving him or her at risk to a variety of infections. Most physicians recommend that patients receive a flu vaccination every year to ward off serious illness, and also recommend immunization against pandemic H1N1 influenza.

But the study found that in patients vaccinated close to the time they get rituximab, the drug does not promote the formation of antibodies to protect against arthritis. Researchers recommended giving the shots well before the rituximab treatment.

The study began long before swine flu emerged, but the effects on that vaccine are expected to be similar. Rituximab is sold under the names Rituxan and MabThera.

Dr. Sander van Assen of the University Medical Center Groningen in the Netherlands studied 23 patients with rheumatoid arthritis who were taking rituximab, 20 patients taking methotrexate and 29 healthy individuals, all of whom were given the seasonal flu vaccine.

Among those taking rituximab, 11 received the vaccine four to eight weeks after treatment and 12 were given it six to 10 months after treatment. The team reported in the journal Arthritis & Rheumatism that those given the vaccine in the weeks after treatment developed no protective antibodies, while those given it later developed some antibodies, but not as many as healthy people. Those taking methotrexate developed normal flu protection.

The doctors recommended that patients being treated with the drug be given the vaccines for seasonal flu and H1N1 flu before treatment begins.