Pulliam, J. R. C.,Bellan, S. E.,Gambhir, M.,Meyers, L. A.,Dushoff, J.
Jolanta Piszczek and Eric Parlow1 outlined expected benefits of a stepped-wedge cluster trial (SWCT) design, with specific reference to the Sierra Leone Trial to Introduce a Vaccine against Ebola (STRIVE). STRIVE, however, is not an SWCT, but a phased-rollout trial in which randomisation to immediate or delayed vaccination groups occurs at the individual level (a randomised clinical trial [RCT]) within trial clusters.2 Whereas the SWCT design is advantageous in certain circumstances, many of the benefits described by Piszczek and Parlow1 would not apply to assessment of Ebola vaccine candidates in Sierra Leone.