According to the National Institutes of Health, community immunity (ie, herd immunity) occurs when a significant portion of a community is immunized against a contagious disease, and most members are protected against that disease because of the few opportunities for an outbreak. Successful vaccination reduces infection or infectiousness in certain people, and can decrease risk in other susceptible individuals in the population.

The Advisory Committee on Immunization Practices (ACIP) has revised its recommendations for the use of the typhoid vaccine to include updated information on the 2 currently available vaccines, the epidemiology of enteric fever in the United States, and the importance of vaccination and other preventive methods for typhoid fever.

Patients who present with joint pain and who have traveled recently may be infected with the chikungunya virus, which can closely mimic rheumatoid arthritis (RA). As the number of cases of chikungunya virus increases in the United States, rheumatologists and primary care physicians need to know how to distinguish between the virus and RA.