Stokes left Ketchum last month after spending two years in the agency's healthcare practice working across accounts including the Movember Foundation, PepsiCo, Pfizer and the World Hepatitis Alliance.
Before Ketchum he worked at healthcare PR agency Red Door Unlimited.
Stokes said: "SHED is all about taking a more bespoke, hand-crafted approach to client problems. We focus on two things, creative and technology. Creative ensures we produce cut-through ideas but technology will always drive engagement in that idea."
SHED, which is based in east London, launches with one client, which was not disclosed. Stokes is currently the firm's sole staff member.