CDC-backed study shows differences between Delta and Omicron

While a study out of southern California shows the Omicron variant of the coronavirus is much milder than the Delta, US health authorities continue to insist on vaccination, boosters and masking due to “strained” hospitals.

Centers for Disease Control and Prevention (CDC) director Rochelle Walensky shared on Wednesday the results of the latest study backed by the agency, showing the disparity between the two variants of the SARS-CoV-2 virus.

A team of scientists from the University of California, Berkeley, healthcare provider Kaiser Permanente and the CDC analyzed data from almost 70,000 people in southern California and plugged it into their models. The pre-print results of their study were published on MedRXiv on Tuesday.

Walensky tweeted that the study showed Omicron represented 53% less risk of symptomatic hospitalization, 74% less risk of intensive care admission, and 91% less risk of death, with zero patients requiring ventilators.

This is based on the study that analyzed 52,297 people who tested positive for Omicron and 16,982 with Delta between November 30, 2021 and January 1, 2022. Of those, 235 (0.5%) were hospitalized with Omicron and 222 (1.3%) with Delta infections. 

During a period of both variants circulating, presumed Omicron infections “were associated with substantially reduced risk of severe clinical endpoints and shorter durations of hospital stay,” according to the study.

Walensky wasn’t quite taking a victory lap, however, warning in a follow-up tweet that Omicron may be less severe, but is “much more transmissible.”

“We are seeing the unprecedented impact,” the CDC director said, pointing to over a million positive tests in a single day and “99% of counties with high transmission [and] strained healthcare systems.”

“Protect against Covid-19: get vaccinated + boosted, wear a mask & stay home if sick,” she added.

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