Serotype | OPA GMTs at^{b}: | |||||||
---|---|---|---|---|---|---|---|---|

Prevaccination | Postvaccination | |||||||

Mexican study (n = 142–159) | U.S. study (n = 672–795) | Comparison^{c} | Mexican study (n = 148–155) | U.S. study (n = 709–786) | Comparison^{c} | |||

Ratio | 95% CI | Ratio | 95% CI | |||||

1 | 6 | 5 | 1.1 | 0.94, 1.24 | 120 | 171 | 0.7 | 0.53, 0.94 |

3 | 7 | 7 | 1.0 | 0.84, 1.24 | 88 | 92 | 1.0 | 0.76, 1.20 |

4 | 30 | 16 | 2.0 | 1.23, 3.09 | 1,729 | 2,412 | 0.7 | 0.53, 0.96 |

5 | 7 | 6 | 1.3 | 1.05, 1.52 | 288 | 231 | 1.2 | 0.88, 1.78 |

6A | 57 | 16 | 3.5 | 2.35, 5.32 | 3,380 | 3,331 | 1.0 | 0.75, 1.37 |

6B | 235 | 38 | 6.1 | 3.68, 10.26 | 3,982 | 2,516 | 1.6 | 1.16, 2.15 |

7F | 66 | 7 | 9.2 | 6.55, 12.82 | 3,130 | 1,301 | 2.4 | 1.75, 3.30 |

9V | 264 | 24 | 11.0 | 6.81, 17.86 | 2,416 | 1,416 | 1.7 | 1.22, 2.38 |

14 | 291 | 35 | 8.2 | 5.30, 12.78 | 1,569 | 765 | 2.1 | 1.45, 2.91 |

18C | 70 | 23 | 3.0 | 1.95, 4.60 | 3,063 | 1,828 | 1.7 | 1.22, 2.30 |

19A | 52 | 25 | 2.1 | 1.51, 2.85 | 1,542 | 805 | 1.9 | 1.52, 2.41 |

19F | 26 | 17 | 1.5 | 1.07, 2.21 | 1,104 | 556 | 2.0 | 1.41, 2.80 |

23F | 13 | 8 | 1.6 | 1.20, 2.14 | 879 | 430 | 2.0 | 1.38, 3.03 |

↵a OPA, opsonophagocytic activity; GMT, geometric mean titer.

↵b

*n*values are the numbers of subjects with a valid and determinate OPA titer to the given serotype. The GMTs were calculated using all subjects with available data for the specified blood draw.↵c The ratio of GMTs (Mexican study to U.S. study) was calculated by back transforming the mean difference between the studies on the logarithmic scale. The 95% confidence intervals (CIs) for the ratio are back transformations of a confidence interval based on the Student

*t*distribution for the mean difference of the logarithms of the measures (Mexican study to U.S. study). The statistically significant differences are in bold type.