Psicologia

Measles in the United States

1- The control and virtual elimination of measles in the United States is a public health success that has provided a model for immunization programs in other parts of the developed world. Before measles vaccination was introduced in the United States in the mid-1960s, more than half a million cases of measles were reported each year. Once a vaccine was developed, public health officials set out to use it to control the disease, envisioning eventual global eradication. By the mid-1970s, fewer than 50,000 cases were being reported annually in the United States, but a severe outbreak in Los Angeles in 1977 reminded authorities how tenuous the control of measles was. Compulsory immunization of school children followed — the first in a series of steps that led to the interruption of the transmission of measles in the United States. The most effective of these steps was probably the introduction of a second dose of measles vaccine in 1989, again in response to a large outbreak of disease. At a meeting in March 2000, leaders in the field concluded that "measles is no longer endemic in the U.S.
2- Measles is an acute infectious disease that can affect persons of all ages but is most severe in young infants and adults. Person-to-person transmission occurs through direct contact or droplet spread, and there is some evidence that severity is related to infective dose, so that those who acquire the disease from close household contact have the most severe disease. Infected persons can infect others even before the characteristic rash appears, creating ample opportunity for people who are incubating the disease to travel from a country where the virus is circulating, such as Romania or India (the latter being the probable origin of an outbreak in Boston in the spring and early summer of 2006), and bring the virus with them.
3- At the time of the 2005 outbreak, the level of vaccination coverage in Indiana was 98 percent for the second dose