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Monkeypox DNA levels correlate with virus infectivity in clinical samples, Israel, 2022
Nir Paran1, Yfat Yahalom-Ronen1, Ohad Shifman2
1Department of Infectious Diseases, Israel Institute for Biological Research, Ness-Ziona, Israel.
Summary
Monkeypox virus infectivity in clinical samples strongly correlates with viral DNA levels detected by PCR. A specific PCR threshold (Cq ≥ 35) indicates negative viral cultures, aiding patient risk assessment.
Area of Science:
- Virology
- Infectious Diseases
- Molecular Diagnostics
Background:
- Global spread of monkeypox virus necessitates understanding clinical specimen infectivity.
- Limited data exists on the correlation between diagnostic PCR results and actual virus infectivity.
Purpose of the Study:
- To examine monkeypox virus infectivity in clinical specimens.
- To determine if infectivity correlates with PCR diagnostic results.
- To establish a PCR threshold for predicting negative viral cultures.
Main Methods:
- Correlation analysis between viral DNA quantity in clinical specimens and infectivity assays using BSC-1 cell line.
- Determination of a quantitative PCR (qPCR) threshold cycle (Cq) value.
Main Results:
- A strong correlation was observed between the amount of viral DNA in clinical specimens and virus infectivity.
- A PCR threshold value of Cq ≥ 35 (≤ 4,300 DNA copies/mL) was identified, corresponding to negative viral cultures.
Conclusions:
- PCR testing is a reliable indicator of monkeypox virus infectivity in clinical samples.
- The defined PCR threshold can aid in risk assessment and inform public health guidelines for managing monkeypox patients.
