Antibody levels following WI38 rabies vaccine.

WI38 rabies vaccine lots with varying mouse potency ratios were compared in their ability to induce neutralizing antibody in human volunteers. Three vaccination schedules were used: 0, 7 and 14 days; o,7 and 21 days; and 0,28 and 56 days. Regardless of the mouse potency ratio, antibody was barely or not detectable on the 7th day after the first dose of vaccine. After the second dose, however, there was a very good correlation between mouse potency and antibody level attained. Vaccines with potency ratios above 2 gave comparable results, whether the 0, 7, 14 or 0, 28, 56 schedules were used. The lowest potency vaccine, however, have a much better response when given at 0, 7 and 14 days than at 0, 28, and 56 days. Although the vaccine with the greatest potency ratio produced the highest levels of antibody, very adequate responses were obtained in 100% of recipients after three doses of vaccines having a ratio greater than 2, given at 0, 7, 14 or 0, 7, 21 days.