Table 2.

ELISA results for volunteersa

GroupNo. of volunteersMean SE ± ODRange
Baseline210.097 ± 0.0060.047–0.146
Vaccination one time210.122 ± 0.0110.040–0.258
Vaccination two times210.712 ± 0.0790.087–1.622
• a The ELISA used measured only IgG antibodies. None of the volunteers were positive at the baseline (cutoff, 0.2 OD unit). Two of the 21 volunteers were ELISA positive by 30 days following administration of the first dose of vaccine. One volunteer failed to seroconvert by 30 days following administration of the second dose of vaccine. That same individual was negative by all assays tested at all time points.