“The Families First Coronavirus Response Act (FFCRA or Act) requires the Federal government to provide all of its employees with paid sick leave and, for employees who are covered under Title I of the Family and Medical Leave Act (FMLA), with expanded family and medical leave for specified reasons related to COVID-19. These provisions will apply from April 1, 2020 through December 31, 2020.”
Postal employees are covered under Title 1 of the FMLA.
(An article on FedSmith.com explains the subtle differences between Title 1 and Title 2 of the FMLA.)
It looks like the USPS has already implemented FFCRA, which takes effect on April 1st.