Viral infection neutralization tests: A focus on severe acute respiratory syndrome-coronavirus-2 with implications for convalescent plasma therapy

Viral neutralization tests (VNTs) have long been considered old-fashioned tricks in the armamentarium of fundamental virology, with laboratory implementation for a limited array of viruses only. Nevertheless, they represent the most reliable surrogate of potency for passive immunotherapies, such as monoclonal or polyclonal antibody therapy. The recent interest around therapy with convalescent plasma or monoclonal antibodies for the Covid-19 pandemic has paralleled the revival of VNTs. We review here the available methods by dissecting variations for each fundamental component of the VNT (i.e., virus type and dose, replication-competent cell line, serum, and detection system).

Automated summary

Viral neutralization tests have traditionally been seen as essential tools in fundamental virology, particularly for evaluating passive immunotherapies. The recent resurgence of interest in therapy using convalescent plasma or monoclonal antibodies for Covid-19 has led to a renewed focus on VNTs as reliable surrogates for treatment efficacy. This review explores the various methods available for VNTs, dissecting the key components that contribute to their effectiveness.