[Safety evaluation of tetravalent meningococcal conjugate vaccine in combination with the inactivated poliomyelitis vaccine and diphtheria-tetanus-acellular pertussis vaccine for infants].

<b>Objective:</b> To investigate the safety of the tetravalent meningococcal conjugate vaccine (MPCV-ACYW) in combination with the inactivated poliomyelitis (IPV) vaccine and diphtheria-tetanus-acellular pertussis (DTaP) vaccine for infants aged 3-5 months and provide real-world evidence for the immunization strategy of vaccine combination. <b>Methods:</b> From June to October 2023, a total of 600 3-month-old infants were selected and divided into three groups: control group, mono-vaccination group and combined vaccination group. They were simultaneously or individually vaccinated with MPCV-ACYW, IPV and DTaP vaccines at 3, 4, and 5 months of age, respectively. The incidence rate of adverse reactions within 30 days after each dose was observed. <b>Results:</b> All 600 infants completed at least one vaccination and entered the safety data analysis. The age of the control group (100 infants), the mono-vaccination group (250 infants), and the combination group (250 infants) was (101.20±7.88), (102.26±7.94), and (102.35±7.76) days, respectively. The body lengths were (63.00±3.02), (62.55±3.06), and (63.14±4.02) cm, respectively. The body weights were (6.90±0.77), (6.86±0.94), and (6.99±0.95) kg, respectively. Boys accounted for 49%, 50.4%, and 52.4%, respectively, with no statistically significant differences (all <i>P</i>>0.05). The overall incidence rates of adverse reactions in the control group, mono-vaccination group, and combined vaccination group were 4.00%, 2.80%, and 3.20%, respectively, with systemic adverse reaction rates of 3.00%, 2.40%, and 2.00%. The incidence rates of local adverse reactions were 1.00%, 0.40%, and 1.20%, with no statistically significant differences (all <i>P</i>>0.05). Adverse reactions were mainly grade 1, with incidence rates of grade 1 adverse reactions of 3.00%, 2.00%, and 1.60% in the three groups, and incidence rates of grade 2 adverse reactions of 1.00%, 0.80%, and 1.60%, respectively. No grade 3 or 4 serious adverse reactions occurred, and the differences were not statistically significant (all <i>P</i>>0.05). The adverse reaction symptoms of the three groups were mainly systemic reactions, among which fever and diarrhea symptoms were reported in individual cases in each group, with no statistically significant differences in the incidence rate (all <i>P</i>>0.05). The symptoms of adverse reactions were mostly transient and self-relieved, all of which were cured. <b>Conclusion:</b> The combination of MPCV-ACYW and IPV or DTaP vaccines is safe for infants aged 3-5 months.