Short Communication Combined action of type I and type III interferon restricts initial replication of severe acute respiratory syndrome coronavirus in the lung but fails to inhibit systemic virus spread Tanel Mahlako˜iv,1,2 Daniel Ritz,3 Markus Mordstein,1,2 Marta L. DeDiego,4 Luis Enjuanes,4 Marcel A. Mu¨ller,3 Christian Drosten3 and Peter Staeheli1 Correspondence Peter Staeheli