Evidence of delays in seeking care in Paris during the spring 2020 wave:
"We retrospectively examined consecutive COVID-19 patients suffering from ARF who were treated by the Paris Fire Brigade’s basic life-support (BLS) teams in the prehospital setting.
Data were provided from primary home care providers...
...After having measured the SpO2i/RRi values in COVID-19 patients, we compared them to those of non-COVID-19 patients (i.e., patients with other causes of ARF treated by the BLS teams over the previous 3 years in the same period)...
...The median SpO2i/RRi value was significantly higher than that of patients treated in the previous 3 years"
Jouffroy, R., Jost, D. & Prunet, B. Prehospital pulse oximetry: a red flag for early detection of silent hypoxemia in COVID-19 patients. Crit Care 24, 313 (2020).