From the website of Sewing for Lives:
To date: Over 39,000 mask covers in progress from volunteer seamstresses for 300 healthcare facilities across the United States since 3/21/2020.
We are connecting hospitals and healthcare professionals in need of mask covers with those willing to sew them.
DISCLAIMER: These hand-crafted mask COVERS are not recommended to prevent the spread of disease. They are created to help healthcare professionals preserve the remaining medically approved masks we do have left. This is not intended to be medical advice or guidelines. Please refer to the CDC for up-to-date guidance and see additional information about our process at bottom of [the Sewing for Lives] page.