Introductory evaluation of an oral, killed whole cell enterotoxigenic Escherichia coli plus cholera toxin B subunit vaccine in Egyptian infants.
BACKGROUND
We conducted the first trial to assess the safety and immunogenicity of an oral, killed enterotoxigenic Escherichia coli plus cholera toxin B-subunit vaccine in children <2 years old.


METHODS
Three doses of vaccine or killed E. coli K-12 control were given at 2-week intervals to 64 Egyptian infants, 6 to 18 months old, in a randomized, double blind manner. Adverse events were monitored for 3 days after each dose. Blood was collected before immunization and 7 to 10 days after each dose to assess vaccine-specific serologic responses.


RESULTS
There was no statistically significant intergroup difference in the percentage of subjects reporting the primary safety endpoint (diarrhea or vomiting) after the first (31%, vaccine; 30%, control) or third (14%, vaccine; 18%, control) dose, whereas there was a trend toward greater reporting in the vaccine group after Dose 2 (36%, vaccine; 18%, control; P = 0.052). The percentage of children showing IgA seroconversion after any dose was higher in the vaccine than the control group for recombinant cholera toxin B-subunit (97% vs. 46%), colonization factor antigen I (61% vs. 18%) and coli surface antigen 4 (39% vs. 4%) (P < 0.001 for each comparison). IgG seroconversion rates in the vaccine and control groups were 97 and 21% to recombinant cholera toxin B-subunit (P < 0.001), 64 and 29% for colonization factor antigen I (P < 0.01), 53 and 21% for coli surface antigen 2 (P < 0.05) and 58 and 4% for coli surface antigen 4 (P < 0.001), respectively. The third vaccine dose was followed by augmented IgG antitoxin titers.


CONCLUSIONS
The oral enterotoxigenic E. coli vaccine was safe and immunogenic in this setting in Egyptian infants.
Savarino
Stephen J
SJ
US Naval Medical Research Unit Number 3, Cairo, Egypt. savarinos@nmrc.navy.mil
Hall
Eric R
ER
Bassily
Samir
S
Wierzba
Thomas F
TF
Youssef
Fouad G
FG
Peruski
Leonard F
LF
Abu-Elyazeed
Remon
R
Rao
Malla
M
Francis
Wagdy M
WM
El Mohamady
Hanan
H
Safwat
Mohammed
M
Naficy
Abdollah B
AB
Svennerholm
Ann-Mari
AM
Jertborn
Marianne
M
Lee
Young J
YJ
Clemens
John D
JD
D000276:Adjuvants, Immunologic / Q000008:administration & dosage*; D000284:Administration, Oral; D000917:Antibody Formation; D002772:Cholera Toxin / Q000008:administration & dosage* / Q000276:immunology; D003967:Diarrhea / Q000276:immunology / Q000517:prevention & control; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004534:Egypt; D004927:Escherichia coli Infections / Q000276:immunology / Q000517:prevention & control*; D022361:Escherichia coli Vaccines / Q000008:administration & dosage / Q000009:adverse effects / Q000276:immunology*; D005260:Female; D006801:Humans; D007070:Immunoglobulin A / Q000032:analysis; D007223:Infant; D008297:Male
D000276:Adjuvants, Immunologic; D022361:Escherichia coli Vaccines; D007070:Immunoglobulin A; D002772:Cholera Toxin