Cheng Yandong, Jiang Lei, Ni Jun, Wei Hongxia, Zheng Yaning, Zhang Yingwei, Zhang Zhaoping, Zhou Yi-Hua, Shen Ping
Department of Endocrinology, Nanjing Drum Tower Hospital, Nanjing University Medical School, Nanjing, China.
Department of Laboratory Medicine, Nanjing Drum Tower Hospital, Nanjing University Medical School, Nanjing, China.
Hum Vaccin Immunother. 2025 Dec;21(1):2518654. doi: 10.1080/21645515.2025.2518654. Epub 2025 Jun 18.
China encountered a COVID-19 pandemic shortly after lifting the zero-COVID-19 policy in December 2022. We prospectively investigated the immune responses to SARS-CoV-2 before and after symptom onset of breakthrough infection in individuals vaccinated with inactivated COVID-19 vaccines. Blood samples from 35 vaccinated participants were collected from December 16 to 20, 2022 when they had no symptoms and a second blood sample was collected from each participant from January 4 to 6, 2023. SARS-CoV-2 RNA, anti-SARS-CoV-2 IgG and IgM, interleukin-6 (IL-6), and C-reactive protein (CRP) were measured with commercially available kits respectively. During a period of average 17.0 (±1.6) days, 30 (85.7%) of 35 participants developed toxemia and respiratory symptoms and 34 (97.1%) were defined with SARS-CoV-2 infection based on positive SARS-CoV-2 RNA in pharyngeal swabs (32) and rising titers of anti-SARS-CoV-2 IgG (34). Before symptom onset, 16 (47.1%), 13 (38.2%), and 5 (14.7%) of the infected individuals already had relatively high anti-SARS-CoV-2 IgG titers, elevated IL-6 and CRP respectively. After 17.0 (±1.6) days, the median anti-SARS-CoV-2 IgG level was significantly increased (46.85 vs 359.45 AU/mL, < .001), whereas the proportions of elevated IL-6 and CRP were each remarkably reduced. None of the participants infected with SARS-CoV-2 had detectable anti-SARS-CoV-2 IgM. In vaccinated individuals infected with SARS-CoV-2, specific anamnestic immune responses may initiate before symptom onset and robust immune response may develop in very early phase, which should be a critical mechanism to lessen the severity of COVID-19 and reduce the mortality by COVID-19 vaccination.
2022年12月中国解除新冠疫情防控“动态清零”政策后不久便遭遇了新冠疫情。我们对接种过新冠灭活疫苗的个体在突破性感染症状出现前后对严重急性呼吸综合征冠状病毒2（SARS-CoV-2）的免疫反应进行了前瞻性研究。2022年12月16日至20日，在35名接种疫苗的参与者无症状时采集血样，2023年1月4日至6日从每名参与者采集第二份血样。分别使用市售试剂盒检测SARS-CoV-2核糖核酸（RNA）、抗SARS-CoV-2免疫球蛋白G（IgG）和免疫球蛋白M（IgM）、白细胞介素-6（IL-6）以及C反应蛋白（CRP）。在平均17.0（±1.6）天的时间段内，35名参与者中有30名（85.7%）出现毒血症和呼吸道症状，34名（97.1%）根据咽拭子中SARS-CoV-2 RNA呈阳性（32名）以及抗SARS-CoV-2 IgG滴度升高（34名）被判定为感染了SARS-CoV-2。在症状出现前，16名（47.1%）、13名（38.2%）和5名（14.7%）受感染个体的抗SARS-CoV-2 IgG滴度、IL-6和CRP已分别相对较高。17.0（±1.6）天后，抗SARS-CoV-2 IgG水平中位数显著升高（46.85对359.45任意单位/毫升，P<0.001），而IL-6和CRP升高的比例均显著降低。感染SARS-CoV-2的参与者中无一检测到抗SARS-CoV-2 IgM。在感染SARS-CoV-2的接种疫苗个体中，特异性回忆免疫反应可能在症状出现前就已启动，并且在非常早期阶段可能就会产生强大的免疫反应，这应该是减轻新冠病毒疾病严重程度以及通过接种新冠疫苗降低新冠病毒疾病死亡率的关键机制。
