Background: Patients admitted to the emergency care setting with COVID-19-infection can suffer from sudden clinical deterioration, but the extent of deviating vital signs in this group is still unclear. Wireless technology monitors patient vital signs continuously and might detect deviations earlier than intermittent measurements. The aim of this study was to determine frequency and duration of vital sign deviations using continuous monitoring compared to manual measurements. A secondary analysis was to compare deviations in patients admitted to ICU or having fatal outcome vs. those that were not. Methods: Two wireless sensors continuously monitored (CM) respiratory rate (RR), heart rate (HR), and peripheral arterial oxygen saturation (SpO₂). Frequency and duration of vital sign deviations were compared with point measurements performed by clinical staff according to regional guidelines, the National Early Warning Score (NEWS). Results: SpO₂ < 92% for more than 60 min was detected in 92% of the patients with CM vs. 40% with NEWS (p <.00001). RR > 24 breaths per minute for more than 5 min were detected in 70% with CM vs. 33% using NEWS (p =.0001). HR ≥ 111 for more than 60 min was seen in 51% with CM and 22% with NEWS (p =.0002). Patients admitted to ICU or having fatal outcome had longer durations of RR > 24 brpm (p =.01), RR > 21 brpm (p =.01), SpO₂ < 80% (p =.01), and SpO₂ < 85% (p =.02) compared to patients that were not. Conclusion: Episodes of desaturation and tachypnea in hospitalized patients with COVID-19 infection are common and often not detected by routine measurements.