lead dnt tapper measles outbreak_00021812.jpg
lead dnt tapper measles outbreak_00021812.jpg
Now playing
02:59
2016 hopefuls weigh in on measles vaccine debate
Tom Pennington/Chip Somodevilla/Getty Images
Now playing
02:52
Gupta fact-checks vaccine comments by Trump, Carson
orig Should I get my child vaccinated npr_00003513.jpg
orig Should I get my child vaccinated npr_00003513.jpg
Now playing
01:14
Should I get my child vaccinated?
Now playing
01:26
How vaccines stop the spread of viruses
A single virus particle of measles virus
CDC
A single virus particle of measles virus
Now playing
01:29
Measles: Why not vaccinating your kids can be deadly
pkg orig jimmy kimmel vaccination psa_00005613.jpg
"Jimmy Kimmel Live"/ABC
pkg orig jimmy kimmel vaccination psa_00005613.jpg
Now playing
01:00
Kimmel rips anti-vaxxers in mock PSA
orig polio pakistan arrests vaccine cm_00003008.jpg
orig polio pakistan arrests vaccine cm_00003008.jpg
Now playing
02:12
Parents arrested for not vaccinating children
ac intv burton vaccine heated debate_00000000.jpg
ac intv burton vaccine heated debate_00000000.jpg
Now playing
03:43
Former Congressman: Vaccines linked to autism
ac dnt lah arizona anti vaccine doctor _00010629.jpg
CNN
ac dnt lah arizona anti vaccine doctor _00010629.jpg
Now playing
03:16
Anti-vaccine doctor under investigation
intv amanda peet measels_00041315.jpg
intv amanda peet measels_00041315.jpg
Now playing
05:35
Actress Amanda Peet talks about vaccinating children
MYRTLE BEACH, SC - JANUARY 18: Dr. Ben Carson speaks at the South Carolina Tea Party Coalition convention on January 18, 2015 in Myrtle Beach, South Carolina. A variety of conservative presidential hopefuls spoke at the gathering on the second day of a three day event. (Photo by Richard Ellis/Getty Images)
Getty Images
MYRTLE BEACH, SC - JANUARY 18: Dr. Ben Carson speaks at the South Carolina Tea Party Coalition convention on January 18, 2015 in Myrtle Beach, South Carolina. A variety of conservative presidential hopefuls spoke at the gathering on the second day of a three day event. (Photo by Richard Ellis/Getty Images)
Now playing
03:52
Dr. Carson: No religious exemptions for vaccinations
ac dnt tuchman why we dont vaccinate_00000000.jpg
Margulis Family Photo
ac dnt tuchman why we dont vaccinate_00000000.jpg
Now playing
03:00
Parents speak out: Why we don't vaccinate our children
erin dnt malveaux measles religious exemptions_00010912.jpg
erin dnt malveaux measles religious exemptions_00010912.jpg
Now playing
01:50
Do religious exemptions do more harm than good?
CNN/CNBC
Now playing
02:34
Gupta: Rand Paul's vaccine views are 'dangerous'
Now playing
01:30
Gupta: Vaccines do not cause autism
Among vaccines delayed until a child grows older, the measles-mumps-rubella (MMR) vaccine topped the list.
Thinkstock
Among vaccines delayed until a child grows older, the measles-mumps-rubella (MMR) vaccine topped the list.
Now playing
02:21
Kohn: I regret not vaccinating my kid
ac kaye on doctors treating measles_00012507.jpg
ac kaye on doctors treating measles_00012507.jpg
Now playing
03:58
Doctors struggle to treat unvaccinated kids
ac sot sanjay measles questions_00025814.jpg
ac sot sanjay measles questions_00025814.jpg
Now playing
04:07
Dr. Sanjay Gupta answers your questions about measles
Now playing
04:36
Gupta: Those opposing vaccines are just wrong
Joe Raedle/Getty Images
Now playing
01:57
How did the anti-vaccination movement begin?
ac pkg cohen anti vaccine movement_00023910.jpg
ac pkg cohen anti vaccine movement_00023910.jpg
Now playing
02:45
Measles outbreak fuels vaccine debate
ctn pkg lah californias wealthiest anti vaccine _00023513.jpg
CNN
ctn pkg lah californias wealthiest anti vaccine _00023513.jpg
Now playing
03:47
L.A.: Where the rich don't vaccinate

Story highlights

More than 100 cases of measles have been reported this year

Should you be worried?

What is the fuss over measles vaccines?

Parents: What is your message to parents who don’t vaccinate their kids? Share your video or written perspective on CNN iReport.

CNN —  

To call the news surrounding vaccinations a “debate” is misleading. The scientific and medical consensus is clear: Vaccinations are safe, and they work.

But there are many who choose – for their own reasons – to disregard the recommendations to vaccinate and exercise their right to not do so.

The controversy, then, comes when the anti-vaccination movement gets large enough to reverse advances in the reduction or elimination of certain diseases.

That’s what is happening with the measles. How bad can it be? Here are some guideposts to the issue in context:

What is the current situation?

In simplest terms, as of January 30, there were 102 cases of measles reported across 14 states.

The majority of these cases are related to one outbreak linked to Disneyland in California.

Map: The measles outbreak

Is a 102 cases a lot?

Last year, there were 644 cases of measles reported.

This year’s pace is striking: One month into the new year, the number of measles cases is nearly one-sixth of last year’s total.

A closer look makes this year’s measles outbreak look even worse. Last year’s 644 measles cases is an outlier compared to the previous decade. The number of measles cases in 2014 was the highest since 2000.

Between 2001 and 2011, the median number of measles cases reported per year was 62. (During that period, the highest number of cases in a single year was 220, and the lowest was 37).

Here’s the glass-half-empty view: So far this year, there are already more cases of measles than during an entire typical year. Those are the words of Dr. Anne Schuchat, assistant surgeon general and director of the Centers for Disease Control and Prevention’s National Center for Immunization and Respiratory Diseases.

Is this uptick in measles cases unprecedented?

No, this is not the first time the United States has witnessed an uptick in measles cases since the invention of the measles vaccine.

A brief history of measles in the United States, according to the CDC:

Before the introduction of a live measles vaccine in 1963, the average yearly number of measles cases was 549,000. (Nearly 500 deaths per year were attributed to measles).

Once the measles vaccine was introduced (it was a one-dose shot), there was a huge drop in measles cases.

Then, between 1989 and 1991, there was a resurgence in measles cases. There were 55,000 cases and 123 deaths reported during that period.

Those getting sick were mostly unvaccinated children. But there were also people who had the vaccine and were getting the disease anyway.

In 1989, the medical community’s recommendation was updated to recommend a two-dose vaccination regimen.

The use of two doses was effective. In 2000, endemic measles was declared “eliminated” from the United States.

What is at stake here?

It is a pretty big deal that the United States can say it eliminated measles. This doesn’t mean that measles doesn’t exist here, but that there is not a constant presence of it in an area.

There is the risk that measles could re-establish itself in the United States.

Schuchat, the assistant surgeon general, told reporters the spike in measles cases is troubling.

“This worries me and I want to do everything possible to prevent measles from getting a foothold in the United States and becoming endemic again,” she said.

The CDC points out that people who refuse to vaccinate usually live in the same community. When measles finds its way into these communities, outbreaks are more likely to occur, and controlling the disease becomes harder.

Measles is not a virus that Americans typically spend time worrying about, because for a long time it has not been prevalent. But it is a serious disease. It is a highly communicable respiratory disease caused by a virus and spread through the air.

Measles starts with a fever, runny nose, cough, red eyes and sore throat.

“This is not a problem with the measles vaccine not working,” Schuchat said. “This is a problem of the measles vaccine not being used.”

Why do people choose not to vaccinate?

The research on the effectiveness of the measles vaccine is well-documented. But anecdotes have a powerful sway.

The anti-vaccination crowd got a boost when a British study alleged a link between autism and childhood vaccines. The study was later retracted, and called an “elaborate fraud” by a leading medical publication.

Nonetheless, personal stories of people who claim that vaccines are responsible for autism or other conditions in children find an audience among well-meaning parents.

One Arizona cardiologist, Dr. Jack Wolfson, has become a face of the anti-vaccination movement, because he is a doctor who refuses to vaccinate his children.

“It’s not my responsibility to inject my child with chemicals,” Wolfson told CNN’s Erin Burnett.

The bottom line, of course, is that no matter what the recommendations are, no person or institution can force people to vaccinate their children. Schools and other institutions often have immunization requirements, but there are ways to opt out for religious or personal reasons.

During the last school year, 3.3% of California kindergartners – about 18,200 – were allowed to skip vaccinations, according to the CDC. The vast majority of exemptions were due to personal beliefs.

Journalists at Silk, a platform for creating data visualizations, took California Kindergarten vaccination rate data and found 133 school districts with vaccination compliance rates at 80% or lower.

Why do I keep hearing this being called a debate?

Scientifically, there is no debate. The measles vaccine is effective. Most of those who contract measles, unsurprisingly, are those who are unvaccinated.

But a conversation about the current measles outbreak brings up other ideas – on personal and religious freedoms, skepticism of scientific findings, reach of government regulations – that are inherently political. And here is where the arguments arise.

Some potential Republican presidential contenders have said that vaccinating children should be voluntary, though they walked a fine line.

Kentucky Sen. Rand Paul told radio host Laura Ingraham that he is “not anti-vaccine at all,” but added “most of them should be voluntary.”

New Jersey Gov. Chris Christie said he vaccinates his children to protect “their health and the public health,” but that he understands that “parents need to have some measure of choice as well.”

The science is clear; which policies to craft with that knowledge is what remains to be discussed.