Safety and immunogenicity of a quadrivalent intradermal influenza vaccine in adults.

•Intradermal quadrivalent influenza vaccine (IIV4-ID) was as immunogenic as trivalent vaccines.•IIV4-ID induced superior antibody responses to the B strain not contained in the trivalent vaccine.•A second B strain in IIV4-ID did not change the safety profile compared with trivalent vaccines.•Injection site and systemic reactions were mostly grades 1 and 2 and transient.•IIV4-ID may reduce the risk of trivalent vaccine B strain mismatches with the circulating B strain.