A new study of nearly 70,000 Covid patients in California demonstrates that Omicron causes less severe disease than other coronavirus variants, results that align with similar findings from South Africa, Britain and Denmark, as well as a host of experiments on animals.

Compared with Delta, Omicron infections were half as likely to send people to the hospital. Out of more than 52,000 Omicron patients identified from electronic medical records of Kaiser Permanente of Southern California, a large health system, the researchers found that not a single patient went on a ventilator during that time.

“It’s truly a viral factor that accounts for reduced severity,” said Dr. Lewnard, an epidemiologist at the University of California, Berkeley who was an author of the study, which was posted online on Tuesday and has not yet been published in a scientific journal.

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First identified in Botswana and South Africa in November, the Omicron variant has surged around the world over the past few weeks, faster than any previously known form of the coronavirus. While there’s a lot that scientists have yet to understand about Omicron, the variant is already causing a rise in new cases that may push some hospital systems to the breaking point.

Continue reading “Omicron: What We Know About the New Coronavirus Variant” →

A spate of new studies on lab animals and human tissues are providing the first indication of why the Omicron variant causes milder disease than previous versions of the coronavirus.

In studies on mice and hamsters, Omicron produced less damaging infections, often limited largely to the upper airway: the nose, throat and windpipe. The variant did much less harm to the lungs, where previous variants would often cause scarring and serious breathing difficulty.

“It’s fair to say that the idea of a disease that manifests itself primarily in the upper respiratory system is emerging,” said Roland Eils, a computational biologist at the Berlin Institute of Health, who has studied how coronaviruses infect the airway.

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A Johnson & Johnson booster shot provided strong protection against the Omicron variant, greatly reducing the risk of hospitalization, according to a clinical trial in South Africa.

The study, which compared more than 69,000 boosted health care workers with a corresponding group of unvaccinated South Africans, found that two shots of the vaccine reduced the risk of hospitalization from Omicron by about 85 percent. In comparison, another study in South Africa found that two shots of the Pfizer-BioNTech vaccine reduced the risk of hospitalization by about 70 percent.

Continue reading “J&J’s booster shot provides strong protection against severe disease from Omicron, a study says.” →