Rate and clinical characteristics of mumps reinfection

: Mumps infection is anecdotally believed to occur only once over a lifetime. However, in recent years, it has gradually come to be recognized among pediatricians that mumps reinfection is not a rare condition, and some criteria for the mumps reinfection have been proposed. One of the widely accepted criteria is levels higher than 25.8 IU/dl of serum IgG antibodies against the mumps virus and lower than 2.0 IU/dl of serum IgM antibodies. From July 2010 to June 2011, 45 patients with acute swelling of the major salivary gland(s) were enrolled into our survey of mumps reinfection in Tsuchiura Kyodo General hospital. Serum IgG and IgM antibodies against the mumps virus were measured at the initial visit. Ten cases were diagnosed as having primary infection with the mumps virus, while the other 10 cases were diagnosed as having reinfection with the mumps virus according to the criteria. The present study suggests that mumps reinfection is a common condition in patients with acute swelling of the major salivary glands in adulthood.