Measles, which afflicted most American children with red blotches just two generations ago, is nearing extinction in the United States, a feat that some health officials liken to the victories against smallpox and polio.
Federal health officials logged only 37 measles cases nationwide in 2002, down from 116 the year before. California also recorded the fewest cases in its history, five, down from 40 in 2001.
"This has been a dramatic success story of the vaccination program," said Dr. Paul Offit, chief of infectious diseases at Children's Hospital of Philadelphia and a member of the U.S. Advisory Committee on Immunization Practices.
The success seen in the United States, however, only accentuates the failures in the developing world. Globally, measles remains the leading cause of vaccine-preventable deaths among children younger than 5. Thirty million children worldwide contract the virus annually, and 745,000 died from it in 2001 -- half of them in Africa.
In 1990, the World Summit for Children set a goal of vaccinating 90% of children worldwide against measles by 2000. It didn't come close. The global immunization rate hovered around 70% throughout the decade, according to UNICEF. Coverage in sub-Saharan Africa dropped from 62% in 1990 to 50% in 1999.
Some call this performance inexcusable given the effectiveness and low cost of the vaccine -- less than a dollar per child. But others note that measles has been eclipsed by other major health concerns such as eradicating polio and treating AIDS.
"It's unacceptable for children to die from measles, when definitely they could be protected by immunization," said Mohammad Jalloh, a UNICEF spokesman. "That's why we are moving now to make sure that we intensify the campaigns."
The progress in the Western Hemisphere is, at least, a reminder of what is possible. Cases have declined from a high of about 250,000 in 1990 to an all-time low of 548 in 2001. Because of outbreaks in Venezuela and Columbia, that number increased to 2,572 last year.
"The countries in this region have demonstrated that it's possible to eradicate this disease, as was the case of polio," said Gina Tambini, director of vaccines and immunization at the Pan American Health Organization. The Western Hemisphere rid itself of polio in 1991, while the disease remained a problem in many other areas.
Before the first measles vaccine was approved 40 years ago, the virus affected up to 4 million U.S. children a year, hospitalizing 100,000 and killing several thousand.
It is the complications of measles, including pneumonia and encephalitis, that can prove lethal. The disease -- different from German measles, or rubella -- typically begins with a cough, conjunctivitis and fever of 103 to 105 degrees. After about three days, a red rash begins on the face and eventually covers the body. The virus is highly contagious through coughing and sneezing.
U.S. health officials attribute their success against measles in large part to a 1989 recommendation that all school-age children receive a second dose of vaccine, on top of the first dose given at 12 to 15 months. That move was prompted by recurrent measles outbreaks among school-age children who were not vaccinated as babies or whose vaccinations didn't take.
Health experts also credit a quick response by state and federal leaders to a surprise measles epidemic among preschoolers in major urban areas, including Los Angeles, in the late 1980s.
More than 7,000 measles cases were reported in Los Angeles County alone during the outbreak, which ended in 1991. About 2,700 county residents were hospitalized and 40 died. Many of those cases were among Latino preschoolers, some of whose families had recently migrated from Latin America.
In response to the outbreak, officials nationwide extended hours at public health centers and set up immunization clinics in churches and housing projects. Since 1993, fewer than 1,000 cases have been reported in the United States annually, and since 1996, more than 90% of infants have been vaccinated against measles.
"Everyone is trying very hard and doing a good job to immunize children, and we're seeing the effects of that," said Maureen Kolasa, an epidemiologist with the National Immunization Program at the Centers for Disease Control and Prevention in Atlanta.
Today, measles cases in the United States have become a matter of curiosity and historical interest.
"Most of our pediatricians in training have never seen measles and may never see measles," said Dr. Paul Krogstad, a pediatric infectious disease specialist at UCLA, who himself has treated only two children with the virus. "I would like to say that about many more diseases."
Even with the remarkable progress, some parent groups think the federal government needs to conduct more research on the effects of the measles-mumps-rubella vaccine, saying they believe it causes autism and other disorders in some children. No link to autism has been scientifically established.
Medical experts say it will be difficult for the nation to eradicate the disease entirely. Because the virus has a 10- to 12-day incubation period, people can contract it elsewhere, travel to the United States feeling fine and develop measles here. For that reason, vaccinations are not likely to end soon.
The progress in the United States and other First World countries throws the failures of vaccination efforts in the Third World into high relief. Some doctors question the decision by international health officials to focus first on polio eradication.
Measles can actually be more deadly than polio. Polio causes paralysis in fewer than 1% of cases and can lead to death by asphyxiation. Measles is fatal in about 5% of cases in sub-Saharan Africa; the rate is higher in areas suffering from drought, famine or humanitarian crises. In the United States before the vaccine was introduced, measles killed about only one or two of every 1,000 patients.
"If you had to pick the disease that really kills people, measles is far more important than probably polio," Offit said.
Polio eradication became a worldwide goal in 1988, in large part because Rotary International championed the cause and had raised $246 million. But measles elimination lacked financial support until recently.
The polio vaccine was also considered easier to administer because it is given orally; the measles vaccine is injected and requires a health worker to do so.
In the last couple years, though, world health groups have devoted more resources to reducing measles.
In early 2001, the American Red Cross organized a $200-million, five-year Measles Initiative to reduce deaths from the virus in Africa. The goal is to vaccinate all children at risk -- about 200 million -- in up to 36 sub-Saharan countries. The program's leaders believe that if they succeed, they can prevent 1.2 million deaths by 2005 and reduce the annual measles death toll to near zero.
In less than two years, the Measles Initiative has delivered the vaccine to more than 70 million children in 16 African countries.
The strategy is to conduct an initial immunization campaign targeting all children 9 months to 15 years old and then to come back every three or four years to vaccinate all children born since the previous effort. Countries are also urged to continue routine immunization of all 9-month-olds.
"Measles is so infectious, it's unforgiving," said Dr. Bradley Hersh, a medical officer for the World Health Organization's immunization program in Geneva. "Measles has the ability of finding pockets of low vaccine coverage and creating outbreaks. The challenge for measles is maintaining high-population immunity."
The executive committee of the World Health Organization voted last week to endorse efforts to cut measles deaths in half by 2005, compared with the 1999 level of nearly 900,000. The resolution will now be considered by the whole World Health Assembly.
European countries have set a goal of 2007 for eliminating measles from their region, and the Middle East and North Africa are trying for 2010.
Dr. Mark Grabowsky, a senior advisor to the Red Cross' international effort, said it's time for the world to take notice that measles elimination is not only feasible but also should be a priority.
"The greatest impact we can have on health in the lives of these children is by doing those things that work," he said. "This is something that works."
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Measles is the world's leading cause of vaccine-preventable deaths of children under age 5.
Hib (Haemophilus influenza, type B): 23.4%
Neonatal tetanus: 11.7%
Yellow fever: 1.8%
Source: World Health Organization
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California and the United States recorded their lowest number of measles cases ever last year, largely because of sustained immunization efforts.
Note: 2002 data are provisional
Sources: U.S. Centers for Disease Control and Prevention; California Department of Health Services; World Health Organization