Measles epidemic on track to be the worst in nearly 20 years: report

According to CNN, the Centers for Disease Control and Prevention reports 626 cases of measles so far this year, with new cases being reported in

That puts this year's outbreak within 42 cases of breaking the record set in 2014 — which puts this year on track to be the worst for measles since the year 2000, when the disease was declared eradicated in the United States.

The cases have previously been reported in Arizona, California, Colorado, Connecticut, Florida, Georgia, Illinois, Indiana, Kentucky, Maryland, Massachusetts, Michigan, Missouri, Nevada, New Hampshire, New Jersey, New York, Oregon, Texas and Washington. The new cases were in Iowa and Tennessee.

Measles is one of the most infectious diseases known to mankind — an unvaccinated person has a 90 percent chance of contracting the disease if exposed to an infected person. While most people recover, in rare cases the disease can cause life-threatening complications like pneumonia and encephalitis, and 1 in 1,000 sufferers will die.

The measles vaccination remains by far the most effective way of preventing epidemics, but its use has declined in some areas of the United States, as parents in certain communities reject the vaccine over fears and conspiracy theories about health risks or autism.

Lawmakers in some states have recently sought to limit vaccine exemptions based on religious or philosophical reasons for children enrolling in public schools. Republicans have broadly resisted these pushes.