By Tom Frieden, M.D., MPH - 02/11/15 04:08 PM EST

“Five Chicago Babies Have Measles.”

That headline from just a few days ago brought news none of us hoped we’d hear.

Five children so young they could not be vaccinated against measles had become infected with this highly contagious and potentially deadly disease.

This is exactly what we are concerned about, when we urge everyone who can be vaccinated to get vaccinated.

Vaccinations protect you. They protect your family. And they protect people around you.

I will never forget my first assignment as a new epidemic intelligence service officer with the Centers for Disease Control. I investigated a large outbreak of measles in New York City, mostly among Hispanic children. Many were under a year old, and many became infected when they visited hospital emergency departments or doctors’ offices for other reasons.

Because these infants were too young to be vaccinated, they were particularly susceptible to being infected. So we vaccinated those around them to stop transmission.

Every day, measles kills 400 children somewhere in the world, most of them under age five, and will cause permanent hearing loss or brain damage in many more. And, until we eliminate measles globally, we’ll continue to be at risk in the U.S.

Mothers in Africa travel many kilometers by foot or on motorbike to get their children vaccinated. They know the devastation measles can cause. They’ve seen it firsthand. They don’t want that fate for their children.

Now, the United States is facing a measles outbreak of more than 100 people, most associated with the outbreak that started in Southern California in December and has now spread to several states and Mexico.

Additional cases not related to this outbreak have also been reported in the United States this year. By the first week of February, more than 120 people had been infected with measles, and the number is increasing.

We don’t know for sure how the California outbreak began, but, like every other chain of transmission in the U.S. over the past 15 years, it’s likely someone got infected with measles when they visited overseas, then brought the disease home to the United States and spread it to others. Nearly 90 percent of people getting measles in this outbreak didn’t have documentation of vaccination.

Measles is remarkably infectious — possibly the most infectious disease known.  If you are not vaccinated or do not have immunity from having already had measles, you can get it just from being in the same space where a person with measles left two hours before — even if that person was not yet very ill. You could also contract the disease, for example, in an auditorium with just one measles patient many seats away from you.

Measles would be a far greater threat in the United States if it weren’t for the measles vaccine, which has now been successfully used for more than 50 years. It’s widely administered through childhood immunization programs around the world. In the past 14 years alone, it has been given to more than 2 billion people worldwide and prevented more than 15 million deaths.

In the United States, immunization programs have become a victim of their own success. Because measles no longer circulates here unchecked as it once did, people have forgotten how serious this disease can be.

But measles is not just a disease of the past. If we don’t take action now, it could become a disease of our future.

Vaccination is not just a way to protect your own kids. It’s also a way to protect the children around you.

With every child not vaccinated, it becomes ever more likely that those who cannot be vaccinated — the baby next door or the kid with leukemia down the street — will become seriously ill or even die from this completely preventable disease.

All parents are concerned about the health and safety of their kids. At the CDC, we’re parents and grandparents, too, and we do everything we can so no child in this country gets ill from measles, becomes hearing impaired or brain damaged, or dies from a disease that could have been so easily prevented.

Both my kids are fully vaccinated against measles and other diseases. Study after study shows the measles vaccine is safe and that it works.

For the past 20 years, the federal Vaccines for Children program has provided the measles vaccine at no cost to children who might not otherwise be vaccinated because of inability to pay. Now, under the Affordable Care Act, health insurance plans must cover the cost of vaccinations, including for measles.

Every parent wants to do what is best for their children. The more children are vaccinated, the safer all children will be.

Vaccination is not only the best — it’s the only — strategy that can protect our children from measles.

Frieden has been the director of the Centers for Disease Control and Prevention since 2009.