Several people who received this year's flu vaccine still got sick. The severe strain of H3N2 swiftly swept the globe leaving scores of people with chills, aches, fever, severe nausea, and in some cases, hospitalization.

Why?

When global health experts met in early 2014 to predict and select the strains to include in the coming season's flu vaccine, the specific type of H3N2 virus they chose began to mutate or "drift." The flu bug seemed to say, "I see what you're doing, so I'm going to change."

By the time H3N2 began taunting us with it's new armor, the flu shot you and I received this fall has been rendered only 23 percent effective. According to public health officials, it's usually closer to 60 percent.

That’s not the case this year. Even in people who got vaccinated [there was the flu]." - Brendan Flannery, CDC epidemiologist

By the time flu season hit, two-thirds of H3N2 viruses making people sick with the flu were not included in the vaccine.

The result has been what the CDC calls a "moderately severe" flu season thus far.

According to the Daily Beast, public health officials have insisted that those who get vaccinated are still better off. After all, the vaccine does protect against multiple strains of flu, including types that could still surface late in the season, and can make symptoms milder even in people who get sick.