Here is a link to the actual study. I would take a look at the limitations discussed in the Discussion section. https://www.cdc.gov/mmwr/volumes/70/wr/mm7031e2

Here is a link to the actual study. I would take a look at the limitations discussed in the Discussion section. https://www.cdc.gov/mmwr/volumes/70/wr/mm7031e2.htm https://www.cdc.gov/mmwr/volumes/70/wr/mm7031e2.htm