Measles virus

Since the introduction of a measles virus vaccine, many countries have mounted an effective immunization program which has essentially eliminated measles as a major childhood disease in those countries. However, as a result of vaccine failure or the failure to be vaccinated, a recent and persistent shift in the susceptible population towards young adults has been recorded. In the case of measles, severity of illness and mortality rates are highest among adults. Thus, serology has become increasingly important as a tool for determining the immune status of the young adult population entering college or the military. In addition, the linkage between measles infection and premature delivery or spontaneous abortion supports screening pregnant mothers for susceptibility. Classified as a paramyxovirus, measles produces a highly contagious respiratory infection. The disease is spread during the prodromal phase through direct contact with respiratory secretions in the form of droplets.

The immune response to infection (or vaccination) with measles virus is rapid and characteristic: Measles specific IgM and IgG begin to appear in the circulation simultaneously. The IgM response is relatively shortlived (1-3 months), while the IgG response is sustained, resulting in lifelong immunity. Therefore, the identification of circulating measles specific IgM antibodies is useful in defining a primary infection.

Since the presence of circulating IgG antibody to measles virus is indicative of previous infection or vaccination, screening the young adult population about to enter college or the military, pregnant women, and other individuals at risk, for seropositivity, is a valuable tool for determining their immune status.

The sensitivity, specificity, and reproducibility of enzyme-linked immunoassays is comparable to other serological tests for antibody.