The disclosure provides synthetic (e.g. recombinant) pneumococcal saccharides comprising one or more repeat unit(s) →4)-β-D-Glcp-(1→4)-[Gro-(2→P→3)]-β-D-Galp-(1→4)-β-L-Rhap-(1→. Also provided are conjugates comprising a →4)-β-D-Glcp-(1→4)-[Gro-(2→P→3)]-β-D-Galp-(1→4)-β-L-Rhap-(1→, immunogenic compositions, vaccines and their use in preventing or treating infection by Streptococcus pneumoniae.