Early Low-Molecular-Weight Heparin Administration is Associated with Shorter Time to SARS-CoV-2 Swab Negativity

Background Antiviral and immune-modulating properties of low-molecular-weight heparin (LMWH) against Coronaviridae have been reported by in vitro studies, but no in vivo evidence is yet available. We sought to know whether the timing of prophylactic doses of LMWH during the course of COVID-19 may affect the time to SARS-CoV-2 nasal-oropharyngeal swab negativization. Methods Retrospective monocentric cross-sectional study on patients requiring sub-intensive ward admission due to first SARS-CoV-2 infection and undergoing early (EH; within 7 days from COVID-19 signs and symptoms onset) versus delayed prophylactic LMWH (DH; after 7 days). SARS-CoV-2 RNA was measured by reverse transcription real-time PCR according to scheduled time points: first swab after 2 weeks from COVID-19 onset, then at 1-week intervals until negativity. Results Time to SARS-CoV-2 swab negativity was shorter in EH (38 patients) compared with DH (55 patients): 22 versus 37 days (P=0.004). The number of confirmative negative swabs in EH was significantly higher compared with DH at week 2 (21.1% versus 3.6%; P=0.017) and 4 (60.0% versus 19.6%; P