Hi there. My information comes from doctors that dh works with, of which I am not one! Haha. Based on what they said, I don't think it would be impossible for complications to arise from Zika later in pregnancy, in the same way that the flu virus can cause complications in a higher risk pregnancy. They always tell pregnant women to get their flu shots! But the main cause of concern here is the brain and skull abnormalities that can occur as a result of Zika, and what they are saying is that once the brain is formed, this is no longer a risk.
In other words, if the mom has a high-risk pregnancy and something like the flu could devastate the life of her baby, I wouldn't be traveling south any time soon just to be safe. (Though the chances of being bitten by a Zika carrying mosquito are still very low here.) But I'm pretty sure those moms aren't planning trips to Disney anyway.