Multiple site quantification of SARS-CoV-2 RNA in vital organs: Implications for postmortem sampling

SARS-CoV-2 exhibits broad organ tropism, with viral RNA detectable in extrapulmonary tissues after death. However, variation between anatomical sites within the same organ remains poorly characterized and may influence postmortem sampling and interpretation. This study investigated intraorgan SARS-CoV-2 RNA distribution by systematic multisite sampling of vital organs obtained during forensic autopsy of an individual with confirmed COVID-19 caused by the Alpha (B.1.1.7) variant. We collected five samples from distinct locations: the brain, heart, each lung, and each kidney. RNA was analyzed by quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) targeting N and E genes. Viral RNA concentrations were expressed as copies per gram of tissue, and within-organ variability was assessed across sites. Mean concentrations were also multiplied by organ weight to provide descriptive estimates of total organ viral RNA content. Viral RNA concentrations showed limited variation between sites within individual organs, with Ct values and copy numbers generally within the same logarithmic range and no significant outliers. The highest concentrations occurred in pulmonary tissue, while viral RNA was consistently detected in the heart, brain, and kidneys, demonstrating multiorgan distribution. Organ-weight-based extrapolation illustrated differences in estimated absolute viral RNA amounts between organs; however, their biological significance cannot be established from this single case. These findings demonstrate relatively homogeneous intraorgan SARS-CoV-2 RNA distribution and suggest extensive multisite sampling may provide limited additional information for quantitative postmortem assessment. Larger studies are required to determine reproducibility across infection stages, viral variants, and postmortem conditions and establish optimal forensic sampling strategies.