The terminology of viruses

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The coronavirus SARS-CoV-2 which causes COVID-19 will change over time and often terminology is inadvertantly misquoted in non-authoritative sources.  SARS-CoV-2 replicates itself by invading a new cell and fusing its genetic material termed RNA (or ribonucleic acid) into the new host. As the RNA is then duplicated, the new copy may not be an exact replica of the original virus.

In understanding the development of the virus changing into different forms, its worth distinguishing between the terms used to describe new versions of viruses generally -

• when an error occurs in duplicating viral RNA these changes are called mutations
• the viruses containing these mutations are termed variants (variants can have a single or many such mutations)
• when a variant virus shows distinct physical difference from the original parent virus, this is termed a strain. All strains are variants but not all variants are strains.