Because people with rheumatoid arthritis have depressed immune systems, flu vaccinations are recommended for them. 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.