The recent measles outbreak in Allegheny County triggered by an infected traveler from India shows that Americans are at risk as long as people here and abroad remain unvaccinated.

While it is now rare for Americans to contract this highly contagious disease, the circumstances are not unique.

As health authorities confirmed an outbreak in Western Pennsylvania, the search for other measles cases intensified in Maryland, Virginia, Washington, D.C., and Iowa.

From 2000 to 2007, the Centers for Disease Control and Prevention reported an average of 63 cases annually in the United States, and they were linked to foreign sources. Last year, the number of reported measles cases more than doubled as a growing number of parents chose not to vaccinate their children.

When measles was eliminated from the Americas in 2002, parents gained a false sense of security. What they fail to realize is that until families everywhere have the opportunity to immunize their children, those living in the United States will face the threat of contracting this preventable disease.

Despite the fact that a safe and effective measles vaccine costs less than $1, in many developing countries parents do not have access to immunization services. Factors such as poverty, poor health systems and a lack of information make it difficult for families to secure preventative medical care. These parents do not have a choice whether to immunize their children; the vaccine is simply not available to those who need it the most.

India currently has the greatest disease burden; an estimated 67 percent of global measles deaths occur in this one country. Every day, more than 360 children die from measles in India. These deaths are due to persistently low vaccination coverage and could be prevented.

The Measles Initiative is a partnership -- led by the American Red Cross, the Centers for Disease Control and Prevention, the United Nations Foundation, UNICEF and the World Health Organization -- committed to addressing this issue. The current goal is to reduce measles deaths globally by 90 percent between 2000 and 2010.

A core strategy of the Measles Initiative is nationwide vaccination campaigns. The work is carried out by local health workers and Red Cross and Red Crescent volunteers who create temporary vaccination posts, visit schools and travel door to door, ensuring that every child receives a measles vaccination. Other health services, such as insecticide-treated mosquito nets to prevent malaria, vitamin A and deworming medicine, are often provided at the vaccination posts. Campaigns typically last a few days and reach the underserved and poorest children.

Following a campaign, new outbreaks disappear and hospital workers begin to close wards that were once needed to treat measles.

Since 2001, the Measles Initiative has supported campaigns in more than 60 countries, vaccinating more than 600 million children. By early 2009, 46 out of 47 priority countries with the highest measles mortality had implemented nationwide campaigns, some more than once. Through these efforts, global measles mortality was reduced by 74 percent (2000-2007).

But as this month's outbreaks show, the global gains, while impressive, are not enough. More than 540 children worldwide still die every day as a result of measles-related complications.

India, the last priority country to adopt the strategy, plans to implement its first set of mass vaccination campaigns in four high-risk states later this year with technical support from the Measles Initiative. Campaigns will also continue in Africa and elsewhere to ensure that the number of measles deaths does not rise again.

As long as measles remains an issue for one nation, it remains a threat to all.