Comparative trial to assess the reactogenicity of the diphtheria-tetanus-acellular pertussis (DTPa) vaccine plus Haemophilus influenzae type B (Hib) conjugate vaccine and that of the diphtheria-tetanus-whole cell pertussis (DTPw) vaccine plus Hib conjugate vaccine, administered in single injection a

Abstract

Background: The diphtheria-tetanus-whole-cell pertussis (DTPw) vaccine is being replaced in Western countries,and in several Spanish Autonomous Communities, by the diphtheria-tetanus-acellular pertussis (DTPa) vaccine. Although the administration of booster doses of DTPw or DTPa and Haemophilus influenzae type b conjugate (Hib) vaccines to toddlers is a current practice ina number of countries, there are few data comparing the reactogenicity profiles of their administration as a single injection.

Subjects and method: An open,prospective, randomised, multicentre trial was conducted to compare the reactogenicity profile of a single injection of DTPa and Hib vaccines (DTPa/Hib) with that of a single injection of DTPw and Hib vaccines (DTPw/Hib) as booster doses to toddlers--previously primed with DTPw and Hib vaccines. 200 children (15.1 +/-1.0 months-old) were randomised to receive DTPa/Hib (group 1;n = 101) or DTPw/Hib (group 2; n = 99) and followed up to 30 days post-vaccination. All subjects received the oral polio vaccine concomitantly. Local and general symptoms were recorded by parents on diary cards.

Results: Incidences of any local reaction and any general symptom <<probably related>>/<<suspected>>to vaccination were reported more frequently in group 2 than in group 1 (p < 0.0001). Pain at the injection site was reported by 29% and 66% of subjects in groups 1 and 2, respectively (p< 0.0001). Pain such that the child cried when limb was moved was also more frequently recorded in group 2 (15%) than in group 1 (1%) (p < 0.0001). Differences in prevalence of any swelling(16% in group 1, 30% in group 2) and swelling > 20 mm reached statistical significance (p (3/4) 0.012). Fever (rectal temperature>= 38 degrees C) was reported by 17% and 41 % in groups 1 and 2 subjects, respectively (p < 0.0001). Fussiness, loss of appetite and restlessness were also more frequently reported in DTPw/Hib subjects and reached statistical significance (at least p = 0.015).Analgesics/antipyretics were prescribed as a prophylactic treatment in only 14% of cases (9 and 19 subjects in groups 1 and 2, respectively;p = 0.0424). Antipyretic treatment after vaccination was significantly more prescribed in group 2 (27 cases) than in group 1 (8) (p <0.015).

Conclusion: The administration of DTPa/Hib as a single injection leads to a better reactogenicity profile than the administration of DTPw/Hib, also as a single injection, as booster doses to toddlers primed with DTPw and Hib vaccines.