A Trial of Acellular Pertussis Vaccine in Hospital Workers during the Cincinnati Pertussis Epidemic of 1993

The safety and immunogenicity of acellular pertussis (AP) vaccine in outbreak control was determined in a randomized, double-blind, controlled trial. Participants received AP vaccine (n=102), which contained 25 microg of pertussis toxoid (PT) and 3 microg of filamentous hemagglutinin (FHA), or licensed meningococcal vaccine (MN; n=97). Local reactions (pain or tenderness, redness, swelling, and induration) and systemic reactions (fever, sleepiness or lethargy, and irritability) were similar among AP and MN vaccinees. One month after AP vaccination, the geometric mean level of IgG anti-PT was 33.1 microg/mL, with 2-fold increases in 85% of patients and 4-fold increases in 73% of patients; for IgG anti-FHA, the respective values were 34.7 microg/mL, 92%, and 63%. After 6 months of follow-up, no serological evidence of pertussis was seen among symptomatic or asymptomatic subjects. However, recent evidence of Bordetella pertussis infection before immunization was shown. Thus, AP vaccine was safe and immunogenic in adults.