Persistence of rabies antibody 5 years after pre-exposure prophylaxis with human diploid cell antirabies vaccine and antibody response to a single booster dose

Abstract

SUMMARYIn 1978, 22 staff members of the National Institute of Virology, Pune, India, were given two doses of human diploid cell antirabies vaccine (HDCV) for primary pre-exposure prophylactic immunization; the interval between the two doses being approximately 4 weeks. Eighteen of these 22 vaccinees were given a booster dose 1 year later. All 18 vaccinees developed protective levels of antibody; most of them had antibody levels exceeding 10 IU/ml.In 1984, 5 years after the booster dose, 11 (79·0%) of 14 vaccinees tested still possessed neutralizing antibody levels ranging from 0·5 IU/ml to 10 IU/ml. Fourteen days after the administration of a booster dose, the antibody levels ranged from 10 to ≥ 100 IU/ml for all except one vaccinee (5·2 IU/ml). These findings demonstrate that the majority of vaccinees retained detectable neutralizing antibody after pre-exposure prophylaxis for as long as 5 years and that a single booster dose thereafter evoked a good antibody response.