 The study found that patients infected with the Omicron strain of SARS-CoV-2 were less likely to develop severe hypoxemia and have a higher chance of surviving 30 and 60 days after being admitted to the hospital than patients infected with the Delta strain. This was primarily due to the fact that more Omicron patients had been vaccinated with three doses of an mRNA vaccine which provided them with better protection against the virus. This article was authored by COVID-19 Omicron Delta Study Group.