Randomized Trial of Inactivated and Live Polio Vaccine Schedules in Guatemalan Infants
1Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, and 2Center for Biologics Evaluation and Research, Food and Drug Administration, Rockville, Maryland; 3Center for Health Studies, University del Valle de Guatemala, and 4Department of Pediatrics, Hospital Roosevelt Guatemala, Guatemala City, Guatemala; 5Instituto de Virología “Dr. J. M. Vanella,” Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Córdoba, Argentina
Background.
The immunogenicity of inactivated poliovirus vaccine (IPV) in developing countries is not well documented. This study compared the immune response to IPV with that to oral poliovirus vaccine (OPV) in Guatemalan infants.
Methods.This was an open‐label, randomized comparison of IPV only, OPV only, or IPV followed by OPV in Guatemalan public health clinics. Serum samples were tested for neutralizing antibodies, and stool samples were tested for Sabin strain polioviruses.
Results.Seropositivity rates 2 months after 2 doses of IPV were 98%–100% for polio types 1, 2, and 3 and were 97.1%, 99.3%, and 92.1% for OPV‐only recipients (
for the response to type 3). One month after the third dose, 100% of IPV‐only recipients had protective antibodies against all 3 types, compared with 99%, 100%, and 97% against polio types 1, 2, and 3 respectively, among recipients of OPV only. Infants who received IPV only had higher geometric mean titers than infants who received OPV only. Maternal antibodies lowered the final antibody responses to IPV but did not prevent the development of protective levels of antibody. Of 191 stool samples from infants who received IPV only, 5 (2.6%) were positive for poliovirus vaccine strains.
Conclusions.IPV alone and IPV followed by OPV are safe and effective for Guatemalan infants.
Received 1 February 2007; accepted 28 March 2007; electronically published 23 July 2007.
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Potential conflicts of interest: E.J.A. has received travel grants from Sanofi Pasteur and GlaxoSmithKline to participate in conferences and is a member of an independent data and safety monitoring board reviewing data for studies conducted by Sanofi Pasteur. S.B.O. has received reimbursement from Sanofi Pasteur for a trip to Guatemala in 2006 for a meeting to discuss the analysis of the research study on which this article is based. N.A.H. and E.J.A. have received salary support through the grant that funded the study. Representatives from Sanofi Pasteur participated in the study design but not in the data collection or analysis; representatives reviewed the manuscript and offered comments. The corresponding author had full access to all data and final responsibility for the decision to submit the manuscript for publication. All other authors report no conflicts.
Financial support: Sanofi Pasteur. Independent funds were used to support statistical analyses, and support for E.L.D. was provided by a Fogarty International Research Scientist Development Award (grant KO1 TW006659).