A growing body of data further strengthened the case for Omicron being a less severe variant than Delta, said Anthony Fauci, MD, chief medical advisor to President Biden, during a White House COVID-19 Response Team phone briefing on Wednesday.
Given certain caveats, “all indications point to a lesser severity of Omicron versus Delta,” Fauci said.
However, he also stressed that the latest data are still “preliminary,” and gleaned from patients in South Africa and the U.K., which may not directly translate to the “demographically diverse” U.S. population.
Fauci highlighted a study published in the International Journal of Infectious Diseases, which compared COVID-19 hospital admissions at a large hospital in the city of Tshwane in the Gauteng Province of South Africa from Nov. 14, 2021 and on (Omicron period) versus prior admissions starting in May 4, 2020 (pre-Omicron period).
Of the 466 cases during the recent Omicron-led wave, 4.5% of patients died compared with 21.3% of the 3,976 cases in previous waves. ICU admissions occurred among 1% versus 4.3%, respectively, and length of hospital stay was 4.0 days versus 8.8 days. Mean age of patients dropped to 39 years from 49 years.
Only 45% of patients in the recent wave required supplemental oxygen compared with 99.5% in the first wave, Fauci noted.
This “decoupling” in the rate of cases, hospitalizations, and deaths in comparison to previous waves “corroborat[es] the clinical findings of milder omicron disease in the hospital,” the authors wrote.