A practical approach to SARS-CoV-2 testing in a pre and post-vaccination era

Abstract

As countries globally are in the process of planning, introducing or implementing mass vaccination strategies while continuing to deal with the ongoing SARS-CoV-2 pandemic, an evolution in testing strategies may be required to minimize spread in mixed vaccinated and non-vaccinated populations. This mini-review explores the key public health questions associated with the widely varying efficacy of commercially available vaccines and their persistence of protection in the context of a growing number of variant virus strains. A new strategy for SARS-CoV-2 testing that accommodates the current and evolving pandemic paradigm is proposed.

Fig. 1

cPass Design and Description. A. cPass Design. The test consists of purified RBD-HRP conjugate (brown) in solution and ELISA plates coated with hACE2 receptor (green) which form a strong complex. When mixed with a sample containing proteins, small molecules or antibodies that block the interaction between the RBD and hACE2 receptor, a low OD450 will be measured after incubation with TMB and stop solution. B. Performing cPass. Sample dilutions are initially mixed with the RBD-HRP solution with incubation for 30 min at 37 °C to permit binding of components to the RBD. If the sample does not contain constituents that bind and block the RBD-hACE2 interaction after a 15 min incubation at 37 °C (bottom four wells) the RBD-HRP will bind to the hACE2-coated wells giving a yellow color after incubation with TMB for 15 min at 37 °C followed by stop solution. If the sample does contain blocking constituents, they will bind to the RBD during the initial 30 min and inhibit the interaction with hACE (top four wells) giving a light yellow or clear color after addition of stop solution. (Fig. 1: is from our recently published, open access article (Taylor, S. C. et al. A New SARS CoV-2 Dual Purpose Serology Test: Highly Accurate Infection Tracing and Neutralizing Antibody Response Detection. J Clin Microbiol, doi:10.1128/jcm.02438–20 (2021)) .

Fig. 1

cPass Design and Description. A. cPass Design. The test consists of purified RBD-HRP conjugate (brown) in solution and ELISA plates coated with hACE2 receptor (green) which form a strong complex. When mixed with a sample containing proteins, small molecules or antibodies that block the interaction between the RBD and hACE2 receptor, a low OD450 will be measured after incubation with TMB and stop solution. B. Performing cPass. Sample dilutions are initially mixed with the RBD-HRP solution with incubation for 30 min at 37 °C to permit binding of components to the RBD. If the sample does not contain constituents that bind and block the RBD-hACE2 interaction after a 15 min incubation at 37 °C (bottom four wells) the RBD-HRP will bind to the hACE2-coated wells giving a yellow color after incubation with TMB for 15 min at 37 °C followed by stop solution. If the sample does contain blocking constituents, they will bind to the RBD during the initial 30 min and inhibit the interaction with hACE (top four wells) giving a light yellow or clear color after addition of stop solution. (Fig. 1: is from our recently published, open access article (Taylor, S. C. et al. A New SARS CoV-2 Dual Purpose Serology Test: Highly Accurate Infection Tracing and Neutralizing Antibody Response Detection. J Clin Microbiol, doi:10.1128/jcm.02438–20 (2021)) .