A total of 4.48 lakh children under the age of five under the old limits of the Chennai Corporation were covered in the second phase of pulse polio vaccination held here on Sunday. Over 4,500 staff and volunteers participated in the drive. A total of 4,95,512 children below the age of five had been enumerated by volunteers and staff. In the first phase, 4.41 lakh children (89 per cent) were covered . In phase II so far, the coverage has been 90.5 per cent.