A STUDY of 80,000 patients with Covid during December 2021 at the Kaiser Permanente Southern California healthcare system comprised a mixture of Delta (16,982) and Omicron (52,297) patients. Hospital admissions were 222 for Delta (1.3 per cent) and 235 for Omicron (0.5 per cent). Rates of ICU admission among Omicron patients were one quarter that of Delta. No Omicron patients required ventilation and they had shorter hospital stays by 3.4 days (70 per cent less than Delta). There were 14 Delta deaths (99.92 per cent recovered) and one Omicron death (99.998 per cent recovered).
The most interesting breakdown of the study statistics is between vaccinated and unvaccinated. Fifty per cent of Delta cases were unvaccinated but only 27 per cent of Omicron cases were unvaccinated. Crucially, unvaccinated individuals face an eightfold reduced risk of infection from Omicron and a sixfold reduced risk of hospitalisation from Delta.
The results support the prevalent view that Omicron is a mild illness affecting the upper respiratory tract, but it is still not an illness that you would deliberately set out to catch as it can become serious in a very small number of cases.
You can view a 30-minute detailed summary of the results here.