Omicron Study in U.K. Bolsters Evidence of Lower Hospital Risks

(Bloomberg) -- Omicron appears to be less severe but more contagious than any other Covid-19 strain to date, a U.K. government study concluded, bolstering research that has shown a lower risk of hospitalization from the fast-spreading variant.

People infected with omicron are 50% to 70% less likely than those with delta to be admitted to hospitals, the U.K. Health Security Agency said Thursday. Omicron patients are also 31% to 45% less likely to arrive at emergency departments than those with delta.

The agency’s data came with an important caveat: While a booster shot improves protection against omicron, its effectiveness starts to wane more rapidly than with delta and is 15% to 25% lower starting 10 weeks after the third dose. The agency also cautioned that the new variant is so infectious that it could still produce significant numbers of severe cases.

The findings build on studies released a day earlier with similar assessments of omicron’s lower hospitalization risk -- rare reassurance regarding a variant whose transmissibility is fast overtaking delta’s. Researchers in Scotland found omicron was associated with a two-thirds lower risk of hospitalization compared to the earlier variant, while a South African study pegged the reduction of hospitalization risk at 80%. 

Another study, from an Imperial College London team working with a larger data set, found that people with omicron were almost half as likely to need an overnight hospital stay.

Separate developments related to prevention and treatment added to the moment of optimism in a pandemic that has killed almost 5.4 million people worldwide and sickened millions more:

• A third dose of AstraZeneca Plc’s Covid vaccine significantly boosted neutralizing antibodies against omicron, according to lab studies at the University of Oxford.
• Merck & Co.’s Covid pill was cleared by U.S. regulators, giving high-risk patients a second at-home treatment just as the omicron variant is causing a surge in cases around the country. The drug, molnupiravir, received emergency authorization on the heels of Pfizer Inc.’s Covid pill being cleared Wednesday. The FDA said Merck’s drug is not recommended for use in pregnant people.

A separate study involving a booster made by China’s Sinovac Biotech Ltd. -- producer of one of the most world’s most widely used Covid vaccines -- didn’t fare as well. That shot didn’t produce sufficient levels of neutralizing antibodies to protect against omicron, according to lab test results published Thursday.

The research suggests that people who’ve received Sinovac’s shot, known as CoronaVac, should seek out a different vaccine for their booster.

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