Outbreaks can occur despite vaccination

No immunization is 100% effective, say infectious disease experts.

By Susan J. Landers, AMNews staff. March 27, 2006.

Washington -- Last summer's outbreak of mumps at a New York camp probably affected more kids than it should have, because no one recognized the swelling that characterizes the disease. Plus, many campers had been vaccinated, so suspicion was low.

Mumps is rare in the United States, and physicians as well as parents have become less likely to suspect it. That was unfortunate for the 31 campers and counselors infected by a 20-year-old counselor who had arrived from the United Kingdom where an outbreak of mumps was raging, noted a report in the Feb. 24 Morbidity and Mortality Weekly Report.

The case illustrates the need to maintain broad vaccination programs that continue to provide immunity for diseases rarely seen, as well as the need to recognize that vaccines aren't 100% effective.

The New York case also demonstrates the importance of recognizing the signs and symptoms of mumps and that physicians should suspect mumps independent of vaccination history, diagnose the disease by using laboratory testing and report it immediately to local health authorities, according to the MMWR report. In this instance, delays in diagnosis and isolating those infected, as well as the failure to report it quickly, likely caused a much larger outbreak than should have occurred, federal authorities said.

The outbreak also raised the question of the effectiveness of at least the mumps portion of the measles, mumps and rubella vaccination.