Persistence of protective anti-poliovirus antibody levels in 4-year-old children previously primed with Picovax®, a trivalent, aluminium-adjuvanted reduced dose inactivated polio vaccine (NCT04448132)
IPV-Al (Picovax®) is a reduced dose, aluminium hydroxide (Al(OH)3)-adjuvanted IPV vaccine developed to meet the demand for effective and affordable inactivated polio vaccines (IPVs). IPV-Al contains one-tenth of the standard dose of IPV. The trial was a phase 4, open-label, multicentre extension trial with healthy subjects who had previously been vaccinated with IPV-Al at 2, 4, 6 months of age in the primary trial (NCT03025750), and again at 15-18 months of age in the first extension trial (NCT03671616). In this trial (NCT04448132), levels of antibodies against poliovirus types 1, 2 and 3 after immunisation with IPV-Al were measured in the trial subjects at the age of 4 years. An additional IPV-Al dose (investigational vaccine) and doses of concomitant vaccines (DTwP/TdaP, DTP/Hib and Varicella, in line with the national vaccination program) were administered and the booster response to IPV-Al was investigated one month after administration. The primary objectives: To describe the seroprotection in 4-year-old children previously immunised with IPV-Al by measuring the response to an additional dose of IPV-Al. The secondary objectives: - To describe the persistence of antibodies against poliovirus types 1, 2 and 3 in subjects previously immunised with IPV-Al measured in blood samples before administration of an additional IPV-Al AJV dose - To describe the booster effect of an additional IPV-Al AJV dose in subjects previously immunised with IPV-Al - To describe the levels of antibodies against poliovirus types 1, 2 and 3 in subjects previously immunised with IPV-Al measured before and after administration of an additional IPV-Al dose - To describe the safety profile of an additional IPV-Al AJV dose given at 4 years of age to subjects previously immunised with IPV-Al Trial population: 163 healthy 4-year-old children of either sex previously immunised with IPV-Al AJV in the primary and the first extension trial. The data available are the core data from the second extension trial, with healthy 4-year old subjects vaccinated with an additional dose of IPV-Al.