Immunological response to Vibrio cholerae O1 infection and an oral cholera vaccine among Peruvians.
A 'double-blind', randomized, placebo controlled study of an oral inactivated whole cell plus recombinant B subunit (WC/rBS) cholera vaccine was conducted during February-March 1992 in Peru in 346 military recruits, 307 (89%) of whom received 2 oral doses of vaccine or Escherichia coli K12 placebo, 2 weeks apart. Paired serum samples were obtained from 155 (50%) of the recipients of 2 doses. An epidemic of cholera took place between doses. No difference in cholera attack rates was detected between vaccine and placebo recipients after one dose (8% versus 14%). Seroconversion (4-fold or higher increase in vibriocidal antibody titres) was detected in 90% and 80% of vaccine and placebo recipients, respectively, with low pre-existing vibriocidal titres (< 0.01). The anti-cholera toxin seroconversion rate among those with low pre-existing titres was higher in vaccinated subjects (97%) than in placebo recipients (68%) (P < 0.01). Administration of 2 doses of WC/rBS vaccine concomitantly with natural V. cholerae O1 infection enhanced the serum anti-cholera toxin response. The immune response to the whole cell component of the vaccine was reduced by high pre-existing vibriocidal antibody titres.
Sanchez
J L
JL
United States Army Medical Research Unit-Brazil, American Consulate-Rio, Unit 3501, USA.
Hayashi
K E
KE
Kruger
H F
HF
Meza
R
R
English
C K
CK
Vidal
W
W
Svennerholm
A M
AM
Taylor
D N
DN
D000293:Adolescent; D000907:Antibodies, Bacterial / Q000096:biosynthesis; D002771:Cholera / Q000453:epidemiology / Q000276:immunology / Q000517:prevention & control*; D002772:Cholera Toxin / Q000276:immunology; D022121:Cholera Vaccines / Q000276:immunology*; D004311:Double-Blind Method; D006801:Humans; D008297:Male; D010568:Peru / Q000453:epidemiology; D011994:Recombinant Proteins / Q000276:immunology; D013997:Time Factors; D014734:Vibrio cholerae / Q000276:immunology*
D000907:Antibodies, Bacterial; D022121:Cholera Vaccines; D011994:Recombinant Proteins; D002772:Cholera Toxin