Swedish researchers have revealed that vaccines do not appear to increase the risk of rheumatoid arthritis.
Their study involved 2,000 people, aged 18 to 70, with RA and more than 2,000 people without RA. Vaccines that were given to the patients included flu, tetanus, diphtheria, tick-borne encephalitis, polio, pneumococcus and hepatitis A, B and C.
The authors report that there was no link between the type or number of vaccines received and the risk of RA.
"This result does not rule out the possibility that vaccinations given earlier in life, or vaccinations that are rare, may trigger the development of RA," Camilla Bengtsson of the Karolinska Institute in Stockholm, Sweden, and colleagues wrote.
The details are due to appear in the journal Annals of the Rheumatic Diseases.