Open Source COVID-19 Response Communities used open hardware approaches to design and distribute medical supplies and devices during the COVID-19 PPE shortage. Examples of these communities include intermediary organizations that played coordinating roles in the response, like Nation of Makers, GetUsPPE, and Open Source Medical Supplies; local grassroots communities that designed and manufactured PPE, like Make4Covid and Makers Unite; and platform communities like NIH 3D Print Exchange.