Lack of association of swine flu vaccine and rheumatoid arthritis.

On the basis of available incidence rates, about 22,000 new cases of definite rheumatoid arthritis would have developed fortuitously among the 45 million recipients of the swine flu vaccine during the year after the immunization program. No excess has been detected. Proportional morbidity studies among all Mayo Clinic patients and among the active-duty personnel of the US Army showed no increase in the number of cases of rheumatoid arthritis after administration of the swine flu vaccine. These results do not support the claims based on anecdotal reports of an association of the vaccine with rheumatoid arthritis.