Author contributions
S.S.C., B.J.C. and V.D. designed the study. E.Y.L.C., L.L.M.P., S.L.L.
and S.S.C. conducted clinical surveillance. S.G. performed sequencing
and analysed the data. S.G., K.M.E. and D.V. designed the figures and
wrote the manuscript with contributions from S.S.C and B.J.C. All
authors discussed and approved the manuscript.