Preliminary safety evaluation of a diphtheria, tetanus, acellular component pertussis, Sabin inactivated poliovirus and Haemophilus influenzae type b combination vaccine (DTacP-sIPV/Hib)

The DTacP-sIPV/Hib combination vaccine is designed to replace the separate administration of diphtheria, tetanus, acellular pertussis, poliomyelitis, and Haemophilus influenzae type b vaccines. By incorporating Sabin strain inactivated poliovirus, DTacP-sIPV/Hib offers advantages in biosafety and manufacturing cost. This study provides a preliminary evaluation of the preclinical safety of a novel DTacP-sIPV/Hib combination vaccine in three animal models. Sprague-Dawley rats were randomly assigned to receive either DTacP-sIPV/Hib or saline by intramuscular injection and were monitored for 14 days for local reactions, body weight, and food intake, followed by necropsy and histopathological examination. Guinea pigs were allocated to negative control, positive control or vaccine groups and sensitized by three intramuscular injections on alternate days; animals were subsequently challenged and observed for allergic reactions. Japanese white rabbits were used in a bilateral self-controlled design, receiving vaccine in one quadriceps and saline in the contralateral side, with macroscopic and histopathological evaluation at 48 h and 16 days post-injection. The candidate DTacP-sIPV/Hib vaccine induced only mild, transient, and reversible local reactions in SD rats and rabbits, indicating acceptable local tolerability under the conditions tested. No detectable effects on body weight or food intake were observed in rats, and no allergic reactions were induced in guinea pigs, suggesting no apparent systemic safety signals in these models. Overall, these findings provide supportive nonclinical safety evidence for the candidate DTacP-sIPV/Hib vaccine and may inform the design and risk assessment of subsequent clinical studies.