Omicron infection appears to be mild, reported by three research teams

Three separate teams of scientists from two continents have found that Omicron infections often cause milder illnesses than early variants of the coronavirus.

Researchers have investigated the course of Omicron through groups in South Africa, Scotland, and the United Kingdom. The results at each setting, although still preliminary, all suggested that variants were less likely to send people to the hospital.

Natalie Dean, a biostatistician at Emory University in Atlanta, said:

Since the discovery of the Omicron subspecies in southern Africa in November, scientists know if it causes more serious illness compared to other variants, and if so, to whom. I’ve been having a hard time.

New studies suggest that this subspecies may have slightly less dangerous biological characteristics than the world-dominant subspecies Delta from summer to the present.

However, it is likely that immunity in these populations also contributed to Omicron’s reduced risk of hospitalization in all three countries. Many infected people already had protection against serious illness, either because of a previous infection or vaccination.

The new study is encouraging, but experts say that the surge that occurs in many countries could flood hospitals with cases of Omicron simply because it spreads much more easily than previous versions of the coronavirus. I warn you that there is.

Christina Ramirez, a biostatistician at the University of California, Los Angeles, said:

Americans need to take a quick test before the holiday event to get together, open windows, and find other ways to improve ventilation, Dr. Ramirez said.

Omicron can cause mild illness on average, but it is still spreading faster than any variant. It is currently the predominant variant in the United States, Europe, and many other parts of the world.

However, promising news arrived from South Africa on Wednesday, suggesting that these surges may not last as long as the previous surges.Omicron is fueling a record number of new cases every day, but officials say report The wave of infection may have peaked on Wednesday.

With the average number of infectious diseases in the United States increasing to 154,000 per day over the past week, federal health officials have added defenses against the heightened threat to hospitals.Food and Drug Administration approved It is the first pill to treat Covid-19 on Wednesday and provides a very effective treatment for severe illness.

Developed by Pfizer and known as Paxrovid, the drug is approved for Covid patients aged 12 years and older at risk of becoming severely ill.Pfizer has that pill Omicron variant..

Three studies from the United Kingdom and South Africa confirm that Americans will gain some protection from vaccination and booster shots against severe illness.is more than 200 million Americans — Over 60% of the population — is now fully vaccinated.

But the United States is lagging behind Other countries, Some of them inoculated more than 80 percent of their population. And only 63 million Americans received the booster. And it provides the strongest protection against both serious illness and infection from Omicron.

South African studies Focused on the surge in Omicron cases since November.. Researchers found that people infected with Omicron had an approximately 70 percent lower risk of hospitalization compared to people infected with other variants of the coronavirus.

The authors speculate that the milder cases may be due in part to the fact that Omicron has successfully re-infected people already infected with Covid-19. Mutants can evade antibodies from previous infections and settle in the body, but may not be able to escape a strong, slow immune response that prevents serious illness.

In South Africa, researchers estimate that about 70 percent of people had a Covid infection before the Omicron wave. About 30 percent are vaccinated. The authors could not distinguish between infection protection and vaccination protection.

They also warned that data were collected in the early stages of the Omicron wave, which has a very low overall infection rate. People infected with relatively mild symptoms may have been more likely to be admitted to the hospital before the ward was full.

of Scotland, Researchers examined Delta and Omicron cases in November and December to find out how many patients with each mutation were admitted to the hospital. Researchers have found that Omicron infection is associated with a two-thirds reduction in the risk of hospitalization compared to the delta type.

Mark Woolhouse, a professor of infectious diseases at the University of Edinburgh and co-author of a new study, said that the dramatic surge in Omicron is still predominant, even if these preliminary results are withheld. People hospitalized very quickly.

Also on Wednesday, a team of researchers at Imperial College London compared Omicron and Delta cases during the first two weeks of December and reported a reduction in hospital visits, albeit less than the reduction found by Scottish colleagues. Did.

Initial estimate Compared to delta mutant cases, individuals infected with Omicron are on average 15-20% less likely to stay overnight or longer in hospitals as a whole, suggesting that they are 40-45% less likely.

The team was able to disperse the consequences of Omicron infections against vaccinated, previously infected, or completely non-immune people. They confirmed the suggestion of South African researchers that acquired immunity helps to reduce ocmicro infections on average.

Differences in English and Scottish study results may also be due in part to differences in what was measured. The team at Imperial College London included people who had just visited the hospital, in addition to those who had to go to bed because of a more serious illness. Scottish researchers only saw hospitalization.

Both teams of scientists warned that their results were still preliminary. For one thing, Omicron has yet to pass through the UK and has not yet made significant progress among older people who may be at high risk of hospitalization.

And even if the individual cases are mild, Omicron still poses a serious risk to the hospital due to the rapid explosion of the cases. “We are not in a place to treat this as a cold,” said Azlagani, co-author of a study at Imperial College London.

William Hanage, an epidemiologist at Harvard TH Chan Public Health School, said the new findings reveal that people who have not been vaccinated and do not yet have Covid are at particularly high risk. rice field.

Omicron is spreading so rapidly that it is likely to become infected in the coming months, he said. If so, they do not have the immunity to slow down the severity of the infection.

“If you haven’t been vaccinated and have never been infected, it’s a bit less severe than Delta,” Dr. Hanage said. “But it’s like saying you’re hitting your head with one hammer instead of two. And the hammer is more likely to hit you now.”

With the flood of new data about Omicron in the last few weeks, there are still many questions about how the next few weeks will evolve and how hospitalization rates will rise.

Chris Robertson, an epidemiologist at the University of Strathclyde and co-author of a Scottish study, warned that the holiday season would delay the collection of data that would require him and others to update their findings. ..

“Usually I do this analysis weekly, but it will take a couple of weeks for other updates to happen,” he said.

Nicholas Reich, a biostatistician and infectious disease modeler at the University of Massachusetts Amherst, said:

But a team of modelers running a project called Covid-19 Scenario Modeling Hub A statement was released Wednesday, revealing that the writing was already on the wall, even if they fine-tuned their predictions.

“The best information we have at this time shows that the threat posed by Omicron is substantive and imminent, and individuals and governments need to be prepared to respond accordingly,” they said. Warned.