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Flu vaccine doesn't work in arthritis patients treated with rituximab

January 6, 2010 | 12:25 pm

PigArthritis patients being treated with the drug rituximab should be given flu vaccinations immediately before treatment begins or several months later, but not in the first two months after treatment, Dutch researchers have found. The vaccine is not dangerous when given after treatment with the drug, but it also provides no benefit, failing to stimulate the production of antibodies against the flu virus. Other drugs used to treat arthritis have no effect on immunization, however.

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 from a variety of infections. Most physicians thus recommend that patients receive a flu vaccination every year to ward off serious illness, and also recommend immunization against pandemic H1N1 influenza.

The disease is typically treated with steroids, methotrexate and a variety of other agents that suppress the autoimmune reaction. One of the newer treatments is with rituximab--a monoclonal antibody sold under the brand names Rituxan and MabThera--which depletes the body's population of B cells that attack the joints. The drug is given in two infusions two weeks apart and its effects last for months. But researchers have been concerned about how depleting B cells would affect vaccination.

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 swine flu preemptively before treatment begins.

In other flu news:

-- New data from the Centers for Disease Control and Prevention showed a mixed bag of flu indicators for the week ending Dec. 26. Only four states were reporting widespread flu activity--Delaware, Maine, New Jersey and Virginia--down from seven the preceding week. Visits to physicians' offices for influenza-like illnesses rose slightly following eight consecutive weeks of declines. Hospitalization rates were unchanged from the previous week, while the proportion of deaths attributed to pneumonia and influenza increased slightly to rise above the epidemic threshold, after dipping below that threshold the preceding week for the first time in 11 weeks. Four pediatric flu deaths were reported during the week, compared with nine the previous week.

-- As of Tuesday morning, 130,386,600 doses of swine flu vaccine were available. Because supplies are becoming more readily available, the Department of Health and Human Services has declared next week National Influenza Vaccination Week. Monday and Tuesday will be focused on healthcare workers and people with high-risk conditions. Wednesday's effort will center on children, pregnant women and caretakers of infants under 6 months old, while Thursday will be focused on young adults. Friday will be devoted to seniors. The department is also conducting a special program this week to vaccinate athletes who will be competing in the Winter Olympics next month in Canada.

-- Canada is loaning Mexico 5 million doses of swine flu vaccine to allow the latter country to meet its immediate vaccination requirements, Canadian Health Minister Leona Aglukkaq said today. Mexico will replace the vaccines by the end of March, by which time it will have received its own shipments. Canada has so far immunized about a third of its population, Aglukkaq said, and the current wave of the pandemic is ebbing there just as it is in the United States.

-- France, meanwhile, is attempting to unload its surplus supplies of the vaccine. The country purchased 94 million doses for its population of 65 million on the assumption that two doses would be required. Now that it is clear one dose will suffice, the country is trying to sell its surplus to other countries at the price it paid for it. About 5 million people have been vaccinated in the country, but immunizations are declining as the pandemic wave has abated.

-- Thomas H. Maugh II