Before the vaccine, nearly all children got measles by the time they were 15. While thought of as a relatively benign childhood disease before 1963, it is estimated that 400 to 500 people died of measles each year. Add to that 48,000 hospitalizations and 4,000 suffering a life threatening complication called encephalitis – an infection of the brain. A deadly measles complication called subacute sclerosing panencephalitis or SSPE has been found to be much more common than previously thought, making childhood vaccination even more important.
Measles is caused by a virus called Rubeola. The virus is spread by contact with aerosols from the nose, mouth or throat of someone infected. Symptoms begin seven to 14 days after viral exposure and include a high fever, cough, runny nose and red watery eyes. Two to three days after symptoms begin, tiny white spots on red background called Koplik spots appear inside the mouth and are a hallmark of measles. After five days, a rash appears, beginning on the face at the hairline and spreads downward over the rest of the body and the fever spikes. Usually measles is self-limiting and after a few days, the fever declines and the rash starts to fade.
Children younger than five and adults 20 years or older are more likely to have measles complications. Common complications include ear infections that can lead to permanent hearing loss as well as diarrhea. Severe complications include pneumonia in about five percent of cases and encephalitis in one in 1000 cases that can be deadly. The most serious complication, SSPE, can occur seven to 10 years after a person has recovered from measles infection and is more prevalent in those infected when they were younger than two years old. In SSPE, the virus persistently infects the brain but proceeds slowly. Initial symptoms are subtle including mild mental deterioration such as forgetfulness, changes in mood or behavior that then progresses to changes in motor functions that include jerking movements of the limbs, trunk and head. Seizures often occur and some people become blind.
As SSPE moves into the advanced stages, people lose the ability to walk with their muscles stiffening or going into spasms. SSPE patients progressively deteriorate and go into a coma leading to a persistent vegetative state. There is no cure and death occurs within one to three years. Alarmingly, recent studies on those that get measles before age five indicate that one in 1,387 have a chance of developing SSPE. For kids infected with measles before their first birthday, this rises to one in 609. This highlights the importance of timely vaccination to protect children from getting measles. Since the first dose of vaccine is given when children are 12 to 15 months old, children under one are susceptible. They depend on others in the community being vaccinated for protection, something called herd immunity. Herd immunity is effective for measles if 83 to 94 percent of the population is vaccinated. Currently, 91.3 percent of U.S. children have received the measles vaccine. Thus, vaccinations not only protect the individuals who receive them but also protect those not yet vaccinated.
Medical Discovery News is hosted by professors Norbert Herzog at Quinnipiac University, and David Niesel of the University of Texas Medical Branch. Learn more at www.medicaldiscoverynews.com.