Grupo de Pesquisa em Biologia e Imunologia de Doenças Infecciosas e Parasitárias, Instituto René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais, Brazil.
Grupo de Imunologia de Doenças Virais, Instituto René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais, Brazil.
Front Immunol. 2023 Jul 14;14:1220600. doi: 10.3389/fimmu.2023.1220600. eCollection 2023.
The pandemic caused by SARS-CoV-2 has had a major impact on health systems. Vaccines have been shown to be effective in improving the clinical outcome of COVID-19, but they are not able to fully prevent infection and reinfection, especially that caused by new variants.
Here, we tracked for 450 days the humoral immune response and reinfection in 52 healthcare workers from Brazil. Infection and reinfection were confirmed by RT-qPCR, while IgM and IgG antibody levels were monitored by rapid test.
Of the 52 participants, 19 (36%) got reinfected during the follow-up period, all presenting mild symptoms. For all participants, IgM levels dropped sharply, with over 47% of them becoming seronegative by the 60th day. For IgG, 90% of the participants became seropositive within the first 30 days of follow-up. IgG antibodies also dropped after this period reaching the lowest level on day 270 (68.5 ± 72.3, p<0.0001). Booster dose and reinfection increased the levels of both antibodies, with the interaction between them resulting in an increase in IgG levels of 130.3 arbitrary units.
Overall, our data indicate that acquired humoral immunity declines over time and suggests that IgM and IgG antibody levels are not associated with the prevention of reinfection.
由 SARS-CoV-2 引起的大流行对卫生系统产生了重大影响。疫苗已被证明能有效改善 COVID-19 的临床结果，但它们不能完全预防感染和再次感染，尤其是新变体引起的感染和再次感染。
在这里，我们跟踪了来自巴西的 52 名医护人员 450 天的体液免疫反应和再次感染情况。通过 RT-qPCR 确认感染和再次感染，通过快速检测监测 IgM 和 IgG 抗体水平。
在随访期间，52 名参与者中有 19 名（36%）再次感染，所有再次感染的参与者均表现出轻微症状。对于所有参与者，IgM 水平急剧下降，超过 47%的人在第 60 天呈血清阴性。对于 IgG，90%的参与者在随访的前 30 天内呈血清阳性。在此期间之后，IgG 抗体也下降，在第 270 天达到最低水平（68.5 ± 72.3，p<0.0001）。加强剂量和再次感染增加了两种抗体的水平，它们之间的相互作用导致 IgG 水平增加了 130.3 个单位。
总体而言，我们的数据表明，获得的体液免疫随时间推移而下降，并表明 IgM 和 IgG 抗体水平与预防再次感染无关。
