新冠灭活疫苗接种对Delta与Alpha变异株感染者临床表现和血清学对比

目的 探讨接种新冠灭活疫苗对SARS-CoV-2 Delta与Alpha变异株感染者的临床表现和血清学反应,为评价疫苗接种对控制新型冠状病毒肺炎（COVID-19）提供科学依据。 方法 收集2021年5月1日—9月30日广州医科大学附属市八医院确诊SARS-CoV-2感染者341例,依据病毒株和依据新冠疫苗接种史分为Delta变异株组、Alpha变异株组和接种组、未接种组。对比Delta和Alpha变异株组及接种组和未接种组的临床表现和血清学反应。结果 Delta变异株组253例（接种组103例和未接种组150例）,Alpha变异株组88例（接种组21例和未接种组67例）。Delta变异株组无症状感染者比例低于Alpha。 Delta变异株组新冠疫苗接种率和疫苗突破性感染率分别为40.7%（103/253）和22.9%（58/253）,均高于Alpha变异株组的23.9%（21/88）和8.0%（7/88）,差异有统计学意义（χ²=8.009,9.484,P<0.01）。Delta变异株组咳嗽、发热比例和病毒峰值载量高于Alpha变异株组(P均<0.001),病毒持续时间长于Alpha变异株组（P<0.001）,SAA、CRP及IFN水平高于Alpha变异株组（P均<0.05）,CD4⁺T细胞计数低于Alpha变异株组（P<0.05）,IgG及IgM水平低于Alpha变异株组（P均<0.001）。两种变异株接种组普通型COVID-19比例低于未接种组（P均<0.01）,病毒峰值载量低于未接种组（P均<0.01）,病毒持续时间短于未接种组（P均<0.01）,SAA、CRP、IL-6水平低于未接种组（P均<0.05）,CD4⁺T细胞水平高于未接种组（P均<0.05）,IgG及IgM水平高于未接种组（P均<0.05）。结论 Delta变异株可引起更高的病毒载量和更严重病程,与疫苗突破性感染相关。新冠灭活疫苗可能通过体液和细胞免疫机制,降低病毒载量、缩短病程和减轻炎症反应,从而减少重症和死亡。

A comparative study of vaccination with inactivated SARS-COV-2 vaccine on the clinical manifestations and serological responses of COVID-19 patients infected by Delta and Alpha variants

Objective To investigate the impacts of vaccination with inactivated SARS-COV-2 vaccine on the clinical manifestations and serological responses of COVID-19 patients infected by Delta and Alpha variants. Methods Clinical and experimental data of 341 confirmed SARS-COV-2 patients were collected from The Eighth Affiliated Hospital of Guangzhou Medical University May 1- September 30, 2021. The subjects were divided into Delta and Alpha variant group according to virus variants, and were divided into vaccinated group and unvaccinated group according to whether they had received inactivated COVID-19 vaccine or not. The clinical manifestations and serological responses of patients with Delta and Alpha variant, and vaccinated and unvaccinated patients with Delta and Alpha variants were compared. Results Totally 253 patients were infected with Delta variant (103 vaccinated and 150 unvaccinated patients), and 88 patients were infected with Alpha variant (21 vaccinated and 67 unvaccinated patients). The proportion of asymptomatic infection in Delta variants group was significantly lower than that in Alpha variants group (P<0.01). Delta variant group of vaccination rates and vaccine breakthrough infection rate was 40.7% (103/253) and 22.9% (58/253), were higher than Alpha variant group was 23.9% (21/88) and 8.0% (7/88), difference was statistically significant (χ²= 8.009, 9.484, P<0.01). The proportion of cough and fever in Delta variant group was higher than that in Alpha variant group (both P<0.01), the peak viral load was higher than that of Alpha variant group (P<0.01), the virus duration was longer than that of Alpha variant group (P<0.01), the levels of SAA, CRP and IFN were higher than those of Alpha variant group (all P<0.05), CD4⁺T cell count was lower than that of Alpha variant group (P<0.05), IgG and IgM levels were lower than those of Alpha variant group (both P<0.01). The proportion of moderate COVID-19 in the vaccinated group was lower than that in the unvaccinated group (P<0.01). In these two variants, the peak viral load of vaccinated group was lower than that of the unvaccinated group (both P<0.01), the duration of virus was shorter than that of unvaccinated group (both P<0.01). The levels of SAA, CRP and IL-6 in the vaccinated group were lower than those in the unvaccinated group (all P<0.05), CD4⁺T cell level was higher than that of unvaccinated group (both P<0.05), IgG and IgM level were higher than those in unvaccinated group (both P<0.05). Conclusions Delta variant can lead to higher viral load and more severe disease course, which is associated with vaccine breakthrough infection. Inactivated vaccines for COVID-19 can reduce severe illness and death by reducing viral load, disease duration and inflammatory response through humoral and cellular immune mechanisms.