Background After receiving a COVID-19 vaccine, most recipients want to know if they are protected from infection and for how long. Since neutralizing antibodies are a correlate of protection, we developed a lateral flow assay (LFA) that measures levels of neutralizing antibodies from a drop of blood. The LFA is based on the principle that neutralizing antibodies block binding of the receptor-binding domain (RBD) to angiotensin-converting enzyme 2 (ACE2). Methods The ability of the LFA was assessed to correctly measure neutralization of sera, plasma or whole blood from patients with COVID-19 using SARS-CoV-2 microneutralization assays. We also determined if the LFA distinguished patients with seasonal respiratory viruses from patients with COVID-19. To demonstrate the usefulness of the LFA, we tested previously infected and non-infected COVID-19 vaccine recipients at baseline and after first and second vaccine doses. Results The LFA compared favorably with SARS-CoV-2 microneutralization assays with an area under the ROC curve of 98%. Sera obtained from patients with seasonal coronaviruses did not show neutralizing activity in the LFA. After a single mRNA vaccine dose, 87% of previously infected individuals demonstrated high levels of neutralizing antibodies. However, if individuals were not previously infected, only 24% demonstrated high levels of neutralizing antibodies after one vaccine dose. A second dose boosted neutralizing antibody levels just 8% higher in previously infected individuals, but over 63% higher in non-infected individuals. Conclusions A rapid, semi-quantitative, highly portable and inexpensive neutralizing antibody test might be useful for monitoring rise and fall in vaccine-induced neutralizing antibodies to COVID-19.
【저자키워드】 COVID-19, SARS-CoV-2, ACE2, Neutralizing antibodies, lateral flow assay, RBD, 【초록키워드】 neutralizing antibody, COVID-19 vaccine, vaccine doses, mRNA vaccine, neutralization, Infection, angiotensin-converting enzyme 2, vaccine dose, lateral flow, Neutralizing activity, Whole blood, respiratory virus, sera, Patient, plasma, seasonal coronavirus, Blood, binding, microneutralization, dose, ROC Curve, second dose, infected individual, infected individuals, individual, measure, recipient, non-infected, SARS-CoV-2 microneutralization assay, Result, tested, assays, receiving, demonstrated, the receptor-binding domain, individuals, semi-quantitative, baseline, patients with COVID-19, 【제목키워드】 neutralizing antibody, point-of-care, development, measure,