Posted on 24 March 2020
One of the greatest challenges to predicting and controlling the course of this pandemic has been obtaining accurate data. The current figures on the number of confirmed cases only scratch the surface: we know that the majority of cases are mild or asymptomatic, and so most go undetected.
To help solve this problem, researchers have been racing to develop a test for anti-SARS-Cov-2 antibodies – molecules produced by immune cells to specifically target the novel coronavirus. Developing an antibody test is important, as it can be used not only in COVID-19 testing, but can also determine whether a person has been infected in the past.
A preprint article now reports the development of a blood test that is sensitive and specific for coronavirus antibodies. Researchers created a slightly modified version of the SARS-Cov-2 spike protein – the protein that the virus uses to attach to human cells. They then used this protein as a basis for an ELISA assay – a colour coded test that can be used to determine if an antibody (in this case antibodies from subjects’ plasma) can bind to a protein (the altered spike protein).
The assays are sensitive and specific, allowing for screening and identification of COVID19 seroconverters using human plasma/serum as early as 3 days post symptom onset. Importantly, these assays do not require handling of infectious virus, can be adjusted to detect different antibody types and are amendable to scaling.Amanat, F., Nguyen, T., Chromikova, V., Strohmeier, S., Stadlbauer, D., & Javier, A. et al. (2020). A serological assay to detect SARS-CoV-2 seroconversion in humans. doi: 10.1101/2020.03.17.20037713
Knowing what proportion of the population has acquired immunity to COVID-19 will greatly improve modelling of the virus‘s spread, and will help governments to determine what kind of containment measures are necessary.
A serological assay to detect SARS-CoV-2 seroconversion in humans: https://doi.org/10.1101/2020.03.17.20037713