Universidade de São Paulo, Faculdade de Medicina, Departamento de Moléstias Infecciosas e Parasitárias, São Paulo, São Paulo, Brazil.
Universidade de Sao Paulo, Faculdade de Medicina, Laboratorio de Investigação Médica em Virologia (LIM 52), São Paulo, São Paulo, Brazil.
Rev Inst Med Trop Sao Paulo. 2022 Feb 25;64:e19. doi: 10.1590/S1678-9946202264019. eCollection 2022.
Vaccination is a fundamental tool to prevent SARS-CoV-2 infection and to limit the COVID-19 pandemic. The emergence of SARS-CoV-2 variants with multiple mutations has raised serious concerns about the ability of neutralizing antibody responses elicited by prior vaccination to effectively combat these variants. The neutralizing capacity against the Gamma, Delta and Omicron variants of sera from individuals immunized with the CoronaVac vaccine remains incompletely determined. The present study evaluated 41 health care workers at the Faculdade de Medicina of the Universidade de Sao Paulo, in Sao Paulo, Brazil, naive to previous SARS- CoV-2 infection, who were vaccinated with two doses of the CoronaVac SARS-CoV-2 vaccine 28 days apart. Neutralizing antibody levels against the Gamma, Delta, and Omicron variants were measured at 32 and 186 days after the second vaccination. We also measured neutralizing antibodies against Omicron in 34 of these individuals following a subsequent booster immunization with the Pfizer vaccine. Quantification of neutralizing antibodies was performed using the Cytopathic Effect-based Virus Neutralization test. Neutralization antibody activity against the Gamma, Delta and Omicron variants was observed in 78.0%, 65.9% and 58.5% of serum samples, respectively, obtained at a mean of 32 days after the second immunization. This decreased to 17.1%, 24.4% and 2.4% of sera having activity against Delta, Gamma and Omicron, respectively, at 186 days post-vaccination. The median neutralizing antibody titers at 32 days were 1:40, 1:20 and 1:20 against Gamma, Delta and Omicron, respectively, and decreased to an undetectable median level against all variants at the later time. A booster immunization with the Pfizer vaccine elicited neutralizing antibodies against Omicron in 85% of subjects tested 60 days after vaccination. We conclude that two doses of the CoronaVac vaccine results in limited protection of short duration against the Gamma, Delta and Omicron SARS-CoV-2 variants. A booster dose with the Pfizer vaccine induced antibody neutralizing activity against Omicron in most patients which was measurable 60 days after the booster.
接种疫苗是预防 SARS-CoV-2 感染和限制 COVID-19 大流行的基本手段。具有多种突变的 SARS-CoV-2 变体的出现，引起了人们对先前接种疫苗所引起的中和抗体反应有效对抗这些变体的能力的严重关注。CoronaVac 疫苗免疫个体的血清对 Gamma、Delta 和 Omicron 变体的中和能力仍不完全确定。本研究评估了巴西圣保罗大学医学院的 41 名卫生保健工作者，他们以前没有 SARS-CoV-2 感染史，间隔 28 天接种了两剂 CoronaVac SARS-CoV-2 疫苗。在第二次接种后 32 天和 186 天，测量了针对 Gamma、Delta 和 Omicron 变体的中和抗体水平。我们还在这些个体中的 34 人在随后用辉瑞疫苗进行加强免疫后测量了针对 Omicron 的中和抗体。使用基于细胞病变效应的病毒中和试验来定量中和抗体。在第二次免疫后平均 32 天，分别有 78.0%、65.9%和 58.5%的血清样本观察到针对 Gamma、Delta 和 Omicron 变体的中和抗体活性。这一比例在接种后 186 天分别下降至针对 Delta、Gamma 和 Omicron 的 17.1%、24.4%和 2.4%。32 天时的中和抗体滴度中位数分别为 1:40、1:20 和 1:20 ，针对 Gamma、Delta 和 Omicron，在稍后的时间里，所有变体的中和抗体滴度均降至无法检测的中位数水平。辉瑞疫苗的加强免疫在接种后 60 天测试的 85%的受试者中引起了针对 Omicron 的中和抗体。我们得出结论，两剂 CoronaVac 疫苗对 Gamma、Delta 和 Omicron SARS-CoV-2 变体的保护作用有限且持续时间短。辉瑞疫苗的加强剂量在大多数患者中诱导了针对 Omicron 的抗体中和活性，在加强后 60 天可测量到。
