Cumulative frequency profiles of rotavirus-specific antibodies in breast milk specimens from mothers in India, Vietnam, Korea and the United States. Milk specimens were tested for IgA (A) and neutralizing activity against vaccine strains Rotarix (B), RotaTeq G1 (C), and 116E (D) as described in the text. Nearly all Indian women had an IgA titier >16 versus all other women. The median IgA and neutralizing titers and the distribution of titers for breast milk from Indian women were higher than all others. The values of significance between Indian women and those from Korea, Vietnam, and the United States are indicated. NA indicates neutralizing antibody.