Nag Deb Sanjay, Chaudhry Rajan, Mishra Minakshi, Rai Sudhir, Gupta Minakshi
Anaesthesiology, Tata Main Hospital, Jamshedpur, IND.
Medical Services, Tata Main Hospital, Jamshedpur, IND.
Cureus. 2020 Dec 2;12(12):e11845. doi: 10.7759/cureus.11845.
Background COVID-19 immunoglobulin G (IgG) antibodies have been considered to provide protective immunity and its immunoassays have been widely used for serosurveillance. In our serosurveillance on an industrial workforce of randomly selected 3296 subjects, COVID-19 IgG antibody positivity was reported in 7.37% (243) subjects. However, when 30 days later, eight of the 243 COVID-19 IgG antibody-positive individuals complained of symptoms suggestive of COVID-19 infection and were confirmed as COVID-19 infection by reverse transcription-polymerase chain reaction (RT-PCR), their COVID-19 IgG antibodies were retested. Seven of the eight previously IgG positive individuals had lost their protective antibodies. Methods Subsequently, a prospective clinical trial was planned by repeating the test for IgG antibodies on the remaining earlier positive 235 individuals at 45-65 days after their initial test. Only 201 of the 235 individuals consented and participated in the non-randomized single-arm observational trial. Results Only 28.36% (57/201) retained their IgG antibodies and 70.15% (141/201) had lost their IgG antibodies. Three cases reported equivocal results on retesting. Conclusions Our findings show that the protective COVID-19 IgG antibodies rapidly decline over one to three months. Further studies are needed with a quantitative assay over a period with neutralizing antibodies to establish if its decay can potentially lead to reinfections. Rapidly decaying protective IgG antibodies would impact herd immunity and vaccine durability. It is critical for the potential vaccines to generate both protective T- and B-cell immune responses in a sustained manner.
背景 新型冠状病毒肺炎免疫球蛋白G（IgG）抗体被认为可提供保护性免疫，其免疫测定已广泛用于血清学监测。在我们对随机选取的3296名产业工人进行的血清学监测中，报告新型冠状病毒肺炎IgG抗体阳性率为7.37%（243名）。然而，30天后，243名新型冠状病毒肺炎IgG抗体阳性个体中有8人出现新型冠状病毒肺炎感染症状，并经逆转录-聚合酶链反应（RT-PCR）确诊为新型冠状病毒肺炎感染，随后对他们的新型冠状病毒肺炎IgG抗体进行了重新检测。8名先前IgG阳性个体中有7人失去了保护性抗体。方法 随后，计划进行一项前瞻性临床试验，在最初检测后的45至65天，对其余235名早期阳性个体重复检测IgG抗体。235名个体中只有201名同意并参与了这项非随机单臂观察性试验。结果 只有28.36%（57/201）的个体保留了IgG抗体，70.15%（141/201）的个体失去了IgG抗体。3例重新检测结果不明确。结论 我们的研究结果表明，新型冠状病毒肺炎保护性IgG抗体在1至3个月内迅速下降。需要进一步进行研究，采用定量检测方法，在一段时间内检测中和抗体，以确定其衰减是否可能导致再次感染。保护性IgG抗体的快速衰减将影响群体免疫和疫苗持久性。对于潜在的疫苗来说，持续产生保护性T细胞和B细胞免疫反应至关重要。
