According to the Hadith the Prophet Muhammad (saws) used to recite this supplication in the morning when first waking up and in the evening.
“O Allah, I ask you for Afiyah.”
Afiyah is an all encompassing word referring to overall well-being. This can include health, wealth, and safety from anything that may be deemed as harmful.
To be saved from any afflictions, you are in Afiyah.
To be healthy, you are in Afiyah.
To have enough money, you are in Afiyah.
To live, you are in Afiyah.
To have your children protected, you are in Afiyah.
And if you are forgiven and not punished, you are in Afiyah.
In the dua Dunya refers to this worldly life and the akhirah meaning the afterlife.