June 16, 2010
Though often left off the list of the most worrisome diseases, measles poses a major danger, particularly to children under five years of age. At the present time, mortality related to this disease has dropped significantly. There were more than 164,000 measles-related deaths in 2008—which averages out to some 450 deaths per day—compared to 733,000 deaths in 2000 and 2.5 million in 1980. But a spate of severe outbreaks in recent years has proven that there is no room for complacency, but that there are indeed many reasons for concern.
The current strategy to reduce measles-related mortality is based on immunizing the greatest number of children by administering two doses (two injections) instead of one. An inexpensive vaccine has existed for 30 years. It is effective for about 85 percent of the children vaccinated and provides protection for several decades. If greater numbers of children are immunized, the circulation of the virus will be limited. Consequently, the risks for the unprotected population will be limited as well.
A Viral Disease
Measles, a viral illness, is an extremely contagious disease. It propagates through infected droplets emitted by sneezing, coughing, and direct contact with nasal or oropharyngeal secretions of infected individuals. Measles primarily affects children and causes a fever and skin rash. There are significant risks of complications: ear infections, pneumonia, diarrhea, malnutrition, and encephalitis (inflammation of the brain). These complications can result in seizures, blindness, mental retardation, and even death.
In the absence of treatment, measles results in the death of 5 percent to 20 percent of those with the disease. Furthermore, those who recover remain subject to a high risk of mortality in the twelve months that follow the onset of the disease. However, once an individual has had measles, he or she is no longer at risk; the disease affords lifelong protection.
Despite the gains of recent decades, numerous countries have experience measles epidemics in 2009 and 2010. Immunization coverage—the proportion of children in the target age group who are immunized—should be very high and then maintained at this level to both limit the number of cases and deaths and also to prevent the onset of epidemics.
The vaccine is effective for about 85 percent of children immunized, which is to say that out of 100 immunized children, 15 will be non-responders and as such unprotected. If these non-responders do not receive a second dose, and if a portion of the children are unvaccinated, a larger at-risk group is formed as time goes by, one that eventually becomes large enough for an outbreak to occur. On average, immunization coverage of 80 percent translates into occasional cases and deaths and a risk of outbreak every five years or more. At 60 percent coverage, there will be more cases, more deaths, and more frequent outbreaks—every three years or so.
When MSF intervenes in a measles outbreak, our teams strengthen epidemiological surveillance and patient care (treatment of symptoms, malnutrition secondary to measles, etc.) and strive to conduct an immunization campaign in coordination with local officials. MSF has shown that the emergency vaccination of children saves lives.
An Effective, Inexpensive Vaccine
Caring for people with measles involves managing symptoms and preventing complications. The treatment is simple and relies on acetaminophen, antibiotics, ophthalmic ointments, and vitamin A to prevent ophthalmic complications and diarrhea. Nutritional support is necessary because measles is a major risk factor for malnutrition.
The best way to reduce measles-related mortality is to strengthen prevention. The present strategy recommends two doses (two injections) instead of one in order to “catch-up” with those who did not receive the routine immunization and also to catch-up with the non-responders. This objective can be carried out through routine immunization targeting children from 9 to 12 months of age and national immunization campaigns at regular intervals (every two to five years), along with supplementary immunization activities for children from 9 months to 5 years of age.
© 2013 Doctors Without Borders/Médecins Sans Frontières (MSF)