Measles is back in the United States, and with a vengeance. Just last year, the US Centers for Disease Control and Prevention (CDC) reported that the number of measles cases had reached a stunning 20-year high, with 677 cases in 27 states. This is after, mind you, the virus was officially declared eradicated in the Americas in 2002. So who's to blame? Experts and pundits alike point straight to a new wave of "mindful" parents refusing to have their children vaccinated.

But before we start pointing fingers, let's check out some backstory.

Measles in Our Past

According to the CDC, measles is deadliest to young children and pregnant women. Victims of the virus often experience dangerously high fevers and a full-body rash. The virus has also been known to cause tragic stillbirths and even a swelling of the brain (encephalitis) that results in severe mental disability or death.

In the first decade after US doctors and labs started reporting measles cases (in 1912), an average of 6,000 measles-related deaths were recorded each year. By the late 1950s the situation had improved 10-fold with modernized medicine. Unfortunately, an estimated 3 to 4 million US citizens were still annually infected, and those cases resulted in 400-500 deaths and about 48,000 hospitalizations each year.

Thankfully, in 1954 researchers John Enders and Thomas Peebles managed to successfully isolate the virus in a 13-year-old boy. A decade later, that work led to the creation of the first measles vaccine.

The vaccine was quickly introduced to parents and their children, with the CDC asking doctors to promote immunization among children between 12 months and 12 years of age.

Unlike the common flu, measles does not frequently mutate and interact with other strains of itself. In this way, the vaccine has remained highly effective for generations. Combined with vaccines for mumps and rubella (MMR), or even with the addition of varicella (MMRV), early childhood immunization plans resulted in a speedy decline in infections. By the time immunization was common in most continental US states (around 1981) the number of reported cases was dropping by about 80 percent each year. (Scroll to read on...)

By 2000, measles was declared eliminated entirely in the United States, with the only occasional state-side cases occurring after an unvaccinated citizen picked it up when abroad.

Measles Returns

Unfortunately, like all good things, this time of safety appears to have come to an end. For January 2015 alone, the CDC reported a whopping 102 measles cases, 92 percent of which were the result of a single outbreak in California.

That outbreak has since been traced back to Disneyland of all places, with 42 children initially confirmed with the illness. And because measles is an airborne virus, it can travel from host to host quickly, finding its way into a new victim's lungs after being coughed into a room.

What's worse, "persons can be infectious for a few days prior to developing symptoms of measles and may feel well enough to be out and about potentially exposing others," the CDC and California health authorities have warned.

Good Intentions Gone Awry

One question remains though: if most US children are immunized before the age of 12, how the heck did all those kids manage to get the virus and then pass it on to others? Is the MMR vaccine losing its effectiveness?

Not quite. Of the 34 victims who had US vaccination records, 28 of them were reportedly unvaccinated, with the remainder having never completed their vaccination regimen (reducing the effectiveness of the immunization). (Scroll to read on...)

Many experts and health professionals are blaming this on growing fears about vaccines. For almost as long as the MMR vaccine has been around, anecdotal evidence has tied it to an increased risk for developing autism. Experts DO agree that the prevalence of autism has been increasing at the same time that infant vaccination coverage has increased across the country. However, the great majority of the scientific community has long since concluded that this is simply a coincidence, especially as most neurological authorities assert that autism-related factors can only influence the brain prenatally, not 12 months or more after birth.

Unfortunately, not every parent has heard the whole story, and those concerned about exposing their child to unnecessary dangers may choose not to have Junior vaccinated.

"Anti-vaxxers," as the media is calling them, can also be found in religious communities. This is less of a problem in the United States, often isolated to Amish communities for obvious reasons. Still, Canada has also been seeing a rise in the number of cases, largely because its vulnerable and larger religious communities often send missionaries to regions like the Philippines and Vietnam, which continue to face what the World Health Organization (WHO) is calling a massive measles epidemic.

Measles and Mistrust

Still, experts are worried about a fresh wave of anti-vaxxers as well; ones that are opting out of vaccination simply because they don't trust the CDC or the White House.

"It's not that [they] reject vaccination because of their conservative views or exposure to certain media," Kent Schwirian, professor of sociology at The Ohio State University, explained in a recent statement. "It was their lack of confidence in the government to deal with the swine flu crisis that was driving their anti-vaccination views."

In a study recently published in the journal Health Promotion International, Schwirian and his colleagues analyzed national survey data from 2009 that examined Americans' views on a then-new vaccine for the H1N1 virus - commonly known as swine flu.

The study found that people trusting the government's ability to deal with the epidemic were almost three times more likely to take the vaccine than others.

This is despite the fact that the 2009-2010 swine flu was kind of a big deal, with the WHO declaring outbreaks to be part of the first worldwide pandemic in more than 40 years. In the US alone, the virus killed about 12,500 people and sickened a stunning 61 million. (Scroll to read on...)

And yet by the winter of 2010, only 50.4 percent of those who participated in a Pew survey indicated that they were going to get vaccinated. It's important to note that this is during a time that Democratic President Barack Obama was urging citizens to get a flu shot.

"Even in our study, about a third of Democrats said they were not likely to get swine flu vaccine and many of those had low confidence in government," added Schwirian. "I believe it is a lack of confidence in government - not political affiliation - that may unite the anti-vaccination people in our study with those from today."

Political satirist Jon Stewart, named one of the most influential people in the world by Time magazine, and dubbed "the most trusted man in America" by The New York Times, seems to agree. Earlier this week, he even called US citizens out on this behavior, poking fun at anti-vaxxers who would choose not to vaccinate just to spite a president they don't trust. Watch the whole segment, called "Les Measlesrables," here.

"You're Barack Obama! You can't tell people what to do," he emphatically said. "Now half the country just on principle has jumped in their cars and raced off looking for the 'Measles Depot!'"

"I've learned," he added in a grave voice, "there's no red America. There's no blue America. There's just a needlessly sick America."

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