Abstract
A study was performed to compare adverse events and antibody response in term and preterm children vaccinated with diphtheria, tetanus, and pertussis vaccine at 2, 3, and 4 months of age. A total of 124 children were recruited and grouped according to gestational age: 37 weeks or more (n = 52), 34 to 36 weeks (n = 40), and less than 34 weeks (n = 32). Study nurses followed up children 24 hours after each vaccination to record temperature, redness, and swelling at the injection site and any systemic symptoms. Proportions of children experiencing adverse events did not differ between groups. Blood samples were obtained six weeks after the vaccination course at which time all children had protective levels of diphtheria and tetanus antitoxins. Geometric mean antibody titres (95% confidence interval) to pertussis toxin were 2754 (2042 to 3715), 5495 (4074 to 7413), and 3690 (2951 to 4677), to filamentous haemagglutinin were 541 (282 to 1023), 951 (537 to 1698), and 614 (426 to 1023), and to agglutinogens 2 and 3 were 12,106 (6918 to 21,380), 21,330 (13,183 to 34,674), and 22,387 (15,136 to 33,113) in children born at a gestational age of less than 34 weeks, 34 to 36 weeks, and 37 weeks or more respectively. These findings support the current recommendations that preterm children are vaccinated at chronological age according to the national schedule.