Two double-blind randomised controlled studies (phase I and I/II) were performed to assess for the first time the safety and immunogenicity of a recombinant subunit gp350 Epstein–Barr virus (EBV) vaccine in 148 healthy adult volunteers. All candidate vaccine formulations had a good safety profile and were well tolerated, with the incidence of solicited and unsolicited symptoms within a clinically acceptable range. One serious adverse event was reported in the phase I trial which was considered to be of suspected relationship to vaccination. The gp350 vaccine formulations were immunogenic and induced gp350-specific antibody responses (including neutralising antibodies).