Objective: To evaluate the immunogenicity, safety, and immune persistence of the sequential booster with the recombinant protein-based COVID-19 vaccine (CHO cell) in healthy people aged 18-84 years. Methods: An open-label, multi-center trial was conducted in October 2021. The eligible healthy individuals, aged 18-84 years who had completed primary immunization with the inactivated COVID-19 vaccine 3 to 9 months before, were recruited from Shangyu district of Shaoxing and Kaihua county of Quzhou, Zhejiang province. All participants were divided into three groups based on the differences in prime-boost intervals: Group A (3-4 months), Group B (5-6 months) and Group C (7-9 months), with 320 persons per group. All participants received the recombinant COVID-19 vaccine (CHO cell). Blood samples were collected before the vaccination and after receiving the booster at 14 days, 30 days, and 180 days for analysis of GMTs, antibody positivity rates, and seroconversion rates. All adverse events were collected within one month and serious adverse events were collected within six months. The incidences of adverse reactions were analyzed after the booster. Results: The age of 960 participants was (52.3±11.5) years old, and 47.4% were males (455). The GMTs of Groups B and C were 65.26 (54.51-78.12) and 60.97 (50.61-73.45) at 14 days after the booster, both higher than Group A's 44.79 (36.94-54.30) (P value<0.05). The GMTs of Groups B and C were 23.95 (20.18-28.42) and 27.98 (23.45-33.39) at 30 days after the booster, both higher than Group A's 15.71 (13.24-18.63) (P value <0.05). At 14 days after the booster, the antibody positivity rates in Groups A, B, and C were 91.69% (276/301), 94.38% (302/320), and 93.95% (295/314), respectively. The seroconversion rates in the three groups were 90.37% (272/301), 93.75% (300/320), and 93.31% (293/314), respectively. There was no significant difference among these rates in the three groups (all P values >0.05). At 30 days after the booster, antibody positivity rates in Groups A, B, and C were 79.60% (238/299), 87.74% (279/318), and 90.48% (285/315), respectively. The seroconversion rates in the three groups were 76.92% (230/299), 85.85% (273/318), and 88.25% (278/315), respectively. There was a significant difference among these rates in the three groups (all P values <0.001). During the sequential booster immunization, the incidence of adverse events in 960 participants was 15.31% (147/960), with rates of about 14.38% (46/320), 17.50% (56/320), and 14.06% (45/320) in Groups A, B, and C, respectively. The incidence of adverse reactions was 8.02% (77/960), with rates of about 7.50% (24/320), 6.88% (22/320), and 9.69% (31/320) in Groups A, B, and C, respectively. No serious adverse events related to the booster were reported. Conclusion: Healthy individuals aged 18-84 years, who had completed primary immunization with the inactivated COVID-19 vaccine 3 to 9 months before, have good immunogenicity and safety profiles following the sequential booster with the recombinant COVID-19 vaccine (CHO cell).
目的： 评价重组新型冠状病毒（新冠病毒）蛋白疫苗（CHO细胞）在18~84岁人群中异源序贯加强免疫的免疫原性、安全性和持久性。 方法： 采用多中心开放性试验设计，于2021年10月在浙江绍兴市上虞区和衢州市开化县2个研究现场，招募已完成2剂次新冠病毒灭活疫苗（Vero细胞）基础免疫3~9个月的18~84岁健康成年人为受试者；根据接种间隔时间分为A（3~4个月）、B（5~6个月）、C（7~9个月）3组，每组各320例，三组受试者均接种重组新冠病毒蛋白疫苗（CHO细胞）。在加强接种前、接种后14、30、180 d采集血液样本，分析比较不同组间的抗体几何平均滴度（GMT）、抗体阳性率和阳转率。收集接种后1个月内不良事件和6个月内的严重不良事件，分析不良反应发生率。 结果： 960例受试者年龄为（52.3±11.5）岁，男性占47.4%（455例）。加强接种14 d后B组和C组受试者GMT（95%CI）分别为65.26（54.51~78.12）和60.97（50.61~73.45），均高于A组受试者［GMT（95%CI）：44.79（36.94~54.30）］；加强接种30 d后B组和C组受试者的GMT（95%CI）分别为23.95（20.18~28.42）和27.98（23.45~33.39），均高于A组受试者［GMT（95%CI）：15.71（13.24~18.63）］，差异均具有统计学意义（均P<0.05）。加强接种14 d后，A、B、C三组受试者抗体阳性率分别为91.69%（276/301）、94.38%（302/320）、93.95%（295/314），抗体阳转率分别为90.37%（272/301）、93.75%（300/320）、93.31%（293/314），差异均无统计学意义（均P>0.05）；加强接种30 d后，抗体阳性率分别为79.60%（238/299）、87.74%（279/318）、90.48%（285/315），抗体阳转率分别为76.92%（230/299）、85.85%（273/318）、88.25%（278/315），差异均有统计学意义（均P<0.001）。960名受试者序贯加强免疫期间的不良事件发生率为15.31%（147/960），A、B、C三组分别为14.38%（46/320）、17.50%（56/320）、14.06%（45/320）；不良反应发生率为8.02%（77/960），三组分别为7.50%（24/320）、6.88%（22/320）、9.69%（31/320），未发生与接种疫苗有关严重不良事件。 结论： 完成新冠病毒灭活疫苗基础免疫3~9个月的18~84岁健康成年人序贯免疫接种重组新冠病毒蛋白疫苗的免疫原性和安全性均较好。.