In the video with Edwards that has just come to light, CHD once again uses the situation to disparage MMR vaccines. Someone off camera asks Edwards if he had never had measles before, to which he replies that he had gotten an MMR vaccine as a kid, though he didn’t know if he had gotten one or the recommended two doses.

“That doesn’t work then, does it?” the off-camera person asks, referring to the MMR vaccine. “No, apparently not, ” Edwards replies. “Just wear[s] off.”

It appears Edwards had a breakthrough infection, which is rare, but it does occur. They’re more common in people who have only gotten one dose, which is possibly the case for Edwards.

A single dose of MMR is 93 percent effective against measles, and two doses are 97 percent effective. In either case, the protection is considered lifelong.

While up to 97 percent effectiveness is extremely protective, some people do not mount protective responses and are still vulnerable to an infection upon exposure. However, their illnesses will likely be milder than if they had not been vaccinated. In the video, Edwards described his illness as a “mild case.”

The data on the outbreak demonstrates the effectiveness of vaccination. As of April 18, Texas health officials have identified 597 measles cases, leading to 62 hospitalizations and two deaths in school-aged, unvaccinated children with no underlying medical conditions. Most of the cases have been in unvaccinated children. Of the 597 cases, 12 (2 percent) had received two MMR doses previously, and 10 (1.6 percent) had received one dose. The remaining 96 percent of cases are either unvaccinated or have no record of vaccination.

Toward the end of the video, Edwards tells CHD he’s “doing what any doctor should be doing.”