Randomized, placebo-controlled trial of inactivated poliovirus vaccine in Cuba.
BACKGROUND
After poliomyelitis has been eradicated, access to live polioviruses will be highly restricted and the use of oral poliovirus vaccine (OPV) will probably be discontinued. Countries using OPV must decide whether to switch to inactivated poliovirus vaccine (IPV) or stop polio vaccination. Because data on the immunogenicity of IPV in tropical developing countries are limited, we conducted a randomized, controlled trial of IPV in Cuba.


METHODS
The study population consisted of healthy infants born in Havana. A total of 166 infants were randomly assigned to two groups. Group A received a combination of the diphtheria-pertussis-tetanus (DPT) vaccine, the Haemophilus influenzae type b (Hib) vaccine, and IPV (DPT-Hib-IPV) at 6, 10, and 14 weeks of age. Group B, the control group, received a combination of the DPT vaccine and the Hib vaccine at 6, 10, and 14 weeks of age. Another group (group C, 100 infants), which did not undergo randomization at the same time as groups A and B, received the DPT-Hib-IPV combination at 8 and 16 weeks of age. Serum samples were collected before vaccination and at least 4 weeks after the last dose. Stool samples were obtained before and 7 days after challenge with OPV.


RESULTS
The seroconversion rates in group A were 94%, 83%, and 100% for types 1, 2, and 3 poliovirus, respectively. There were no seroconversions in group B. The seroconversion rates in group C were 90%, 89%, and 90% for poliovirus types 1, 2, and 3, respectively. For groups A, B, and C, the virus isolation rates after challenge with OPV were 94%, 91%, and 97%, respectively, and the mean log10 viral titers of any serotype were 3.46, 3.89, and 3.37, respectively. There was one major adverse event, an episode of hypotonia.


CONCLUSIONS
Vaccination with two or three doses of IPV resulted in a rate of seroconversion of at least 90%, except for seroconversion against type 2. The viral titer of OPV shed in the stool after OPV challenge was reduced in both groups receiving IPV. (ClinicalTrials.gov number, NCT00260312 [ClinicalTrials.gov].).
D000914:Antibodies, Viral / Q000097:blood; D016667:Bacterial Capsules; D003462:Cuba; D015721:Diphtheria-Tetanus-Pertussis Vaccine; D005243:Feces / Q000821:virology; D018073:Haemophilus Vaccines; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D011051:Poliomyelitis / Q000276:immunology* / Q000517:prevention & control; D017955:Poliovirus / Q000276:immunology* / Q000302:isolation & purification; D011054:Poliovirus Vaccine, Inactivated / Q000008:administration & dosage / Q000276:immunology*; D011135:Polysaccharides, Bacterial; D017778:Vaccines, Combined
D000914:Antibodies, Viral; D015721:Diphtheria-Tetanus-Pertussis Vaccine; D018073:Haemophilus Vaccines; C044237:Haemophilus influenzae type b polysaccharide vaccine; D011054:Poliovirus Vaccine, Inactivated; D011135:Polysaccharides, Bacterial; D017778:Vaccines, Combined