Washington — Measles is a common childhood disease often eclipsed in international health news by deadly HIV/AIDS and highly pathogenic avian influenza, but new measles outbreaks occurred in the United States and other countries in 2008, and every day, 600 children around the world die from the highly infectious virus.Even though a vaccine was available in 1963, millions of children, especially those in developing countries, are at risk from measles. Children younger than age 5 who are malnourished and have not been immunized are most vulnerable to dying from the disease. Its complications include pneumonia, blindness, diarrhea and encephalitis.
International partnerships and research groups around the world are working to reduce measles deaths globally and to understand whether controlling measles will be more difficult in regions where HIV infection is common.
One group, the Measles Initiative, was established in 2001 and is led by the American Red Cross, the United Nations Foundation, the U.S. Centers for Disease Control and Prevention (CDC), UNICEF and the World Health Organization (WHO).
The initiative provides technical and financial support for vaccination campaigns to governments and communities. Since 2001, it has supported the vaccination of more than 500 million children in more than 60 countries, helping reduce measles deaths by 68 percent globally and 91 percent (based on deaths in 2000) in Africa.
“This vaccine has been available for 45 years and is incredibly inexpensive,” Athalia Christie, senior technical adviser to the American Red Cross–International Services, told America.gov, “We can reach any child in the world in any part of Africa or Asia for less than $1.”
The Measles Initiative supports the four-part WHO-UNICEF joint strategic plan for measles mortality reduction, Christie added.
The strategy includes strengthening routine immunization, providing an opportunity for vaccinated children to receive a second dose of measles vaccine through the public health system or through a targeted campaign, instituting surveillance for measles outbreaks and making sure those who are infected receive proper treatment.
“To eliminate measles, to really stop transmission in a region or a country, you need two doses rather than one,” Dr. William Moss, lead author of a measles-HIV study in Zambia and an associate professor in the Johns Hopkins Bloomberg School of Public Health’s Epidemiology Department, told America.gov.
The second dose, he said, usually given several years after the first dose in the United States, immunizes the small percentage of children who did not respond to the first dose and those who missed receiving the first dose.
WHO recommends a second measles vaccination for all children.
CDC announced August 21 that between January and July, 131 cases of measles in the United States were reported to the agency’s National Center for Immunization and Respiratory Diseases. At least 15 patients, including four children younger than age 15 months, were hospitalized. No deaths were reported.
Of the 131 cases, 17 were importations from Switzerland (3), Italy (3), Israel (2), Belgium (2), India (2), Germany (1), the Peoples Republic of China (1), Pakistan (1), the Russian Federation (1) and the Philippines (1) — countries where outbreaks have been reported among people who have not been vaccinated.
Highly infectious measles is one of the first diseases to reappear when immunization rates fall.
In sub-Saharan Africa, where 1.7 million people were newly infected with HIV in 2007 and 22.5 million people live with HIV, controlling measles may require repeat vaccinations for HIV-infected children, according to the research by Moss and colleagues from the Bloomberg School of Public Health, the Johns Hopkins University School of Medicine, the U.S. Food and Drug Administration, the London School of Hygiene and Tropical Medicine and the University Teaching Hospital in Lusaka, Zambia.
In the study of 690 Zambian children, the scientists found most HIV-infected and uninfected children responded well to the measles vaccine at age 9 months, but those who survived HIV infection lost their protective antibodies over several years.
“What we’ve been very interested in,” Moss said, “and the broader public health question is, whether measles control will be more difficult in regions where HIV infection is common.”
Vaccinated children with HIV in sub-Saharan Africa often do not survive long enough to again become susceptible to measles, but that will change for those who have access to life-saving anti-retroviral therapy.
“These children are going to have increasing access to anti-retroviral therapy,” Moss said, “but what does it do to their immunity to measles? In this sense, measles may be a model for all vaccines.”
The researchers soon will start a study in Zambia with HIV-infected children who are starting anti-retroviral therapy, measuring measles immunity before and after treatment.
“My hypothesis is that their measles immunity does not come back and they would need to be revaccinated,” Moss said. “It’s possible that in the absence of revaccination, if these children have lost their immunity to measles and then start surviving longer because of anti-retroviral therapy, [sub-Saharan Africa] could see more measles as a consequence. That’s why it’s important now to understand whether or not they should be revaccinated.”
Courtsey : Cheryl Pellerin