Efficacy and safety of seven-valent conjugate pneumococcal vaccine in American Indian children: group randomised trial.
BACKGROUND
Streptococcus pneumoniae is the main cause of invasive bacterial disease in children aged younger than 2 years. Navajo and White Mountain Apache children have some of the highest rates of invasive pneumococcal disease documented in the world. We aimed to assess the safety and efficacy of a seven-valent polysaccharide protein conjugate pneumococcal vaccine (PnCRM7) against such disease.


METHODS
In a group-randomised study, we gave this vaccine to children younger than 2 years from the Navajo and White Mountain Apache Indian reservations; meningococcal type C conjugate vaccine (MnCC) served as the control vaccine. Vaccine schedules were determined by age at enrollment. We recorded episodes of invasive pneumococcal disease and serotyped isolates. Analyses were by intention to treat and per protocol.


RESULTS
8292 children enrolled in the trial. In the per protocol analysis of the primary efficacy group (children enrolled by 7 months of age) there were eight cases of vaccine serotype disease in the controls and two in the PnCRM7 group; in the intention-to-treat analysis we noted 11 cases of vaccine serotype disease in the MnCC control group and two in the PnCRM7 group. After group randomisation had been controlled for, the per protocol primary efficacy of PnCRM7 was 76.8% (95% CI -9.4% to 95.1%) and the intention-to-treat total primary efficacy was 82.6% (21.4% to 96.1%).


CONCLUSIONS
PnCRM7 vaccine prevents vaccine serotype invasive pneumococcal disease even in a high risk population. Other regions with similar disease burden should consider including this vaccine in the routine childhood vaccine schedule.
O'Brien
Katherine L
KL
Center for American Indian Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA. klobrien@jhsph.edu <klobrien@jhsph.edu>
Moulton
Lawrence H
LH
Reid
Raymond
R
Weatherholtz
Robert
R
Oski
Jane
J
Brown
Laura
L
Kumar
Gaurav
G
Parkinson
Alan
A
Hu
Diana
D
Hackell
Jill
J
Chang
Ih
I
Kohberger
Robert
R
Siber
George
G
Santosham
Mathuram
M
D001130:Arizona / Q000453:epidemiology; D005260:Female; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D006801:Humans; D007115:Immunization Schedule; D007198:Indians, North American / Q000706:statistics & numerical data*; D007223:Infant; D008297:Male; D022401:Meningococcal Vaccines / Q000276:immunology; D022242:Pneumococcal Vaccines / Q000276:immunology / Q000627:therapeutic use*; D011018:Pneumonia, Pneumococcal / Q000453:epidemiology / Q000276:immunology / Q000517:prevention & control*; D012703:Serotyping; D013296:Streptococcus pneumoniae / Q000276:immunology; D018074:Vaccines, Conjugate / Q000276:immunology / Q000627:therapeutic use
D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D022401:Meningococcal Vaccines; D022242:Pneumococcal Vaccines; D018074:Vaccines, Conjugate; C410218:serogroup C meningococcal conjugate vaccine