Immunization against rabies with rabies immune globulin, human (RIGH) and a human diploid cell strain (HDCS) rabies vaccine

Abstract

A serological study was performed in 16 volunteers and 3 patients to determine the active antibody response after immunization with human diploid cell strain (HDCS) vaccine alone, or in conjunction with Rabies Immune Globulin, Human (RIGH). Where heterologous antiserum from horse or mule together with any rabies vaccine is used for passiveactive immunization, a pronounced interfering effect is observed, depending upon the relative concentrations of preformed rabies antibody given and the rabies virus antigen of the vaccines. When 20 i.u. kg −1 of RIGH were applied simultaneously with vaccine on day 0, followed by a full series of post-exposure antirabies treatment, i.e. six doses of HDCS vaccine on days 0, 3, 7, 14, 30 and 90, no interference was observed. Instead, an additive effect was seen between passive antibody and actively produced antibody. This was reflected by the increase of rabies antibody titer on day 7 post-vaccination, which could be demonstrated by three different assays: MNT, CFT and HIT. From day 14 to day 90, no significant difference was observed between the sero-vaccinated and the control groups, as to logarithmic increase, plateau formation or persistence of neutralizing and HI antibodies. Serum samples obtained on day 455 from 12 individuals representing both study groups revealed comparable antibody values by MNT and HIT. Thus, persistence and level of vaccine-induced antibody to rabies virus, whether produced after vaccine alone or by sero-vaccination, showed no significance differences.