Establishment of national standards of SARS-CoV-2 variants in Taiwan

Objectives: In response to the pandemic, the Taiwan Food and Drug Administration (TFDA) established an initial SARS-CoV-2 RNA national standard based on the original Wuhan strain. However, with the depletion of the first national standard and continued mutation of the virus, the establishment of new national standards was imminent.

Methods: Hence, new candidate national standards were established by heat-inactivation for 30 min for six representative strains of SARS-CoV-2, comprising the original strain and five variants with anticipated concentrations of 7.70 Log₁₀ international units (IU)/mL each. To enhance the credibility of these national standards, the TFDA extended invitations to both domestic and international institutions to participate in a collaborative study. A total of eight participants contributed eleven datasets, incorporating two methods and targeting four distinct genes.

Results: Based on these collective findings, the quantified viral RNA concentrations for each SARS-CoV-2 national standard strain are 7.69, 7.70, 7.69, 7.44, 7.52, and 7.29 Log₁₀ IU/mL with Wuhan, alpha, beta, gamma, delta, and omicron strain, respectively.

Conclusions: These newly established national standards will continue to be made available to the industry, serving as a fundamental reference for the development and quality control of nucleic acid in vitro diagnostic (IVD) reagents in Taiwan.