TABLE 3

Clinical symptoms after oral immunization with either live-attenuated vaccine strain SC602 or wild-type S. flexneri 2a strain 2457T

Time and clinical parameterValue for treatment groupa
SC602 (n = 8) (1 × 1010 CFU)SC602 (n = 8) (1 × 1011 CFU)S. flexneri 2a 2457T (n = 8) (1 × 109 CFU)PBS (n = 10)
After vaccination 1
    No. of cases of diarrheab1162
    Mean day of onset (range)7 (NA)1 (NA)3.8 (1–8)7 (1–9)
    Mean no. of days of illness (range)2 (NA)10 (NA)3.5 (2–9)3.5 (2–5)
    % Colonizationc100100750
    Median duration (range)1 (1–3)4 (1–8)7.5 (2–10)
After vaccination 2
    No. of cases of diarrhea2160
    Mean day of onset (range)2.5 (2–3)1 (NA)2 (1–5)0
    Mean no. of days of illness (range)3 (2–4)5 (NA)6 (2–10)0
    % Colonization1001001000
    Median duration (range)2 (1–3)2 (2–4)5 (1–8)
After vaccination 3
    No. of cases of diarrhea0260
    Mean day of onset (range)0 (NA)1 (NA)2.8 (1–6)0
    Mean no. of days of illness (range)0 (NA)8 (6–10)4 (2–8)0
    % Colonization1001001000
    Median duration (range)2 (1–2)2 (1–3)6 (1–8)
  • a NA, not applicable.

  • b Diarrhea defined as at least one loose-watery stool on at least two consecutive days during the observation period (10 days).

  • c Colonization assessed by plating of HE agar with confirmatory slide agglutination or colony blotting. Negative samples confirmed with ipaH-specific PCR on frozen stool specimens.