Despite the great progress made in the Americas in reducing measles incidence, measles continues to circulate in certain parts of the Americas and in most other countries of the world. The recent public health emergency in Central America has resulted in many displaced persons, especially in Honduras and Nicaragua.
For protection against the elements and for basic nutrition many people have congregated in displaced persons camps. Past experience has shown that due to their high population density, displaced persons camps are at high risk for outbreaks of infectious diseases, including measles. Moreover, the recent influx of large numbers of disaster personnel into Central America increases the risk of measles virus importations. Indeed many of the public health workers now entering the region are coming from parts of the world where measles remains endemic.
Extremely high measles-associated mortality rates have been previously reported from displaced persons camps. Mortality from measles is, however, preventable, and immunization against the disease must be a high priority in emergency relief programs. Efforts are clearly needed to prevent measles outbreaks among camps of displaced persons.
The group at highest risk for dying from measles are children less than 1 year of age. Maternal measles antibody generally wanes between 6 and 9 months of age. It is, thus, recommended that the age of measles vaccination be reduced to 6 months of age in these camps. Infants vaccinated before 12 months of age should receive a second dose of measles-containing vaccine after their first birthday.
While most persons in Central America between 2 and 20 years of age have probably been previously vaccinated in the measles eradication efforts, some may have escaped vaccination and others have been vaccinated, yet for one reason or another, failed to respond to the vaccine and thus remain susceptible to the disease. The recent large measles outbreak in Brazil suggests that there may be a relatively large number of young adults in Latin America who remain susceptible to measles. Young adults living in the conditions of a displaced persons camp may be at high risk for coming into contact with measles virus. Most persons born before 1960, however, likely had natural measles disease and do not need to be vaccinated. For the above reasons, it would seem reasonable to indiscriminately administer measles vaccine to infants, children, adolescents and young adults residing in displaced persons camps.
Based on the above information, the following specific recommendations are made:
PAHO/WHO Special Program for Vaccines and Immunization
Regional Office of the World Health Organization