SARS-CoV-2 genomic and subgenomic RNAs in diagnostic samples are not an indicator of active replication

Persistent RNA can confound COVID-19 tests

29 March 2021

The presence of certain types of coronavirus RNA in a COVID-19 test does not necessarily indicate an active case of the disease.

Researchers from Deakin University in Australia detected fragments of RNA from the SARS-CoV-2 genome in throat and nasal swabs taken up to 17 days after people first screened positive for COVID-19.

They showed how this RNA is protected from degradation by lipid membranes in cells, allowing it to persist well beyond the time of original synthesis.

The RNA, which encodes various coronavirus proteins, is thus not an accurate indicator of ongoing virus replication and gene expression, but rather a possible relic of earlier RNA production.

To avoid falsely diagnosing someone with active COVID-19, the researchers demonstrate how measuring the relative abundance of RNAs in clinical samples can improve the accuracy of existing tests.

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References

1. Nature Communications 11, 6059 (2020). doi: 10.1038/s41467-020-19883-7