IMMUNOGENICITY IN PERUVIAN VOLUNTEERS OF A BOOSTER DOSE OF ORAL CHOLERA VACCINE CONSISTING OF WHOLE CELLS PLUS RECOMBINANT-B-SUBUNIT

Forty-nine subjects received two doses of oral cholera vaccine consist ing of whole cells plus recombinant B subunit; this was followed by a booster dose one year later. After the primary series, a significant ( greater than twofold) increase in the levels of vibriocidal, anti-chol era toxin immunoglobulin G and anti-cholera toxin immunoglobulin A ant ibodies occurred in 54, 88, and 81% of the subjects, respectively. Wit hin one year, titers decreased to levels close to baseline. A booster dose then induced rises similar to those which occurred after the init ial vaccination. The results suggest that 1-year booster doses may be necessary to maintain immunity against cholera in Latin America.