A composition comprising: an immunogenic M protein fragment: (i) consisting of the p145 peptide of SEQ ID NO: 56; (ii) consisting of a variant of (i) consisting of an amino acid sequence at least 90% identical to SEQ ID NO: 56; (iii) comprising the J8 peptide of SEQ ID NO: 58; (iv) comprising a variant of (iii) consisting of an amino acid sequence at least 90% identical to SEQ ID NO: 58; (v) comprising the J8 variant peptide of SEQ ID NO: 59, SEQ ID NO: 60, SEQ ID NO: 61, or SEQ ID NO: 62; (vi) comprising a variant of (v) consisting of an amino acid sequence at least 90% identical thereto; (vii) comprising a derivative of any one of (i) to (vi) consisting of one or a plurality of lysine residues at an N- and/or C-terminus thereof; or (viii) comprising a conjugated derivative of any one of (i) to (vii), consisting of any one of (i) to (vii) being conjugated to a carrier protein, fragment or epitope thereof, wherein said carrier protein does not comprise a sequence of the M protein, and an agent that facilitates restoring or enhancing neutrophil activity, the agent comprising: (a) the SpyCEP peptide of SEQ ID NO: 18; (b) a SpyCEP peptide variant consisting of an amino acid sequence at least 90% identical to SEQ ID NO: 18; (c) the SpyCEP peptide of (a) or the SpyCEP peptide variant of (b) further consisting of one or a plurality of lysine residues at an N- and/or C-terminus thereof; (d) the SpyCEP peptide or the SpyCEP peptide variant of any one of (a) to (c) conjugated to a carrier protein, fragment or epitope thereof; or (e) an antibody or antibody fragment, which binds the SpyCEP peptide or the SpyCEP peptide variant of any one of (a) to (d), for use in a method of eliciting an immune response to group A streptococcal bacteria in a mammal. an immunogenic M protein fragment: (i) consisting of the p145 peptide of SEQ ID NO: 56; (ii) consisting of a variant of (i) consisting of an amino acid sequence at least 90% identical to SEQ ID NO: 56; (iii) comprising the J8 peptide of SEQ ID NO: 58; (iv) comprising a variant of (iii) consisting of an amino acid sequence at least 90% identical to SEQ ID NO: 58; (v) comprising the J8 variant peptide of SEQ ID NO: 59, SEQ ID NO: 60, SEQ ID NO: 61, or SEQ ID NO: 62; (vi) comprising a variant of (v) consisting of an amino acid sequence at least 90% identical thereto; (vii) comprising a derivative of any one of (i) to (vi) consisting of one or a plurality of lysine residues at an N- and/or C-terminus thereof; or (viii) comprising a conjugated derivative of any one of (i) to (vii), consisting of any one of (i) to (vii) being conjugated to a carrier protein, fragment or epitope thereof, wherein said carrier protein does not comprise a sequence of the M protein, and (i) consisting of the p145 peptide of SEQ ID NO: 56; (ii) consisting of a variant of (i) consisting of an amino acid sequence at least 90% identical to SEQ ID NO: 56; (iii) comprising the J8 peptide of SEQ ID NO: 58; (iv) comprising a variant of (iii) consisting of an amino acid sequence at least 90% identical to SEQ ID NO: 58; (v) comprising the J8 variant peptide of SEQ ID NO: 59, SEQ ID NO: 60, SEQ ID NO: 61, or SEQ ID NO: 62; (vi) comprising a variant of (v) consisting of an amino acid sequence at least 90% identical thereto; (vii) comprising a derivative of any one of (i) to (vi) consisting of one or a plurality of lysine residues at an N- and/or C-terminus thereof; or (viii) comprising a conjugated derivative of any one of (i) to (vii), consisting of any one of (i) to (vii) being conjugated to a carrier protein, fragment or epitope thereof, wherein said carrier protein does not comprise a sequence of the M protein, and an agent that facilitates restoring or enhancing neutrophil activity, the agent comprising: (a) the SpyCEP peptide of SEQ ID NO: 18; (b) a SpyCEP peptide variant consisting of an amino acid sequence at least 90% identical to SEQ ID NO: 18; (c) the SpyCEP peptide of (a) or the SpyCEP peptide variant of (b) further consisting of one or a plurality of lysine residues at an N- and/or C-terminus thereof; (d) the SpyCEP peptide or the SpyCEP peptide variant of any one of (a) to (c) conjugated to a carrier protein, fragment or epitope thereof; or (e) an antibody or antibody fragment, which binds the SpyCEP peptide or the SpyCEP peptide variant of any one of (a) to (d), (a) the SpyCEP peptide of SEQ ID NO: 18; (b) a SpyCEP peptide variant consisting of an amino acid sequence at least 90% identical to SEQ ID NO: 18; (c) the SpyCEP peptide of (a) or the SpyCEP peptide variant of (b) further consisting of one or a plurality of lysine residues at an N- and/or C-terminus thereof; (d) the SpyCEP peptide or the SpyCEP peptide variant of any one of (a) to (c) conjugated to a carrier protein, fragment or epitope thereof; or (e) an antibody or antibody fragment, which binds the SpyCEP peptide or the SpyCEP peptide variant of any one of (a) to (d), for use in a method of eliciting an immune response to group A streptococcal bacteria in a mammal.