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How Omicron Is Different Than Delta - The New York Times

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In less than two months, the Omicron variant of the coronavirus has spread around the globe and caused a staggering number of new infections.

Omicron now accounts for more than 99.5 percent of new infections in the United States, according to estimates from the Centers for Disease Control and Prevention. The nation reported as many as 800,000 new cases a day in mid-January, more than three times as many as at any previous point in the pandemic.

Scientists have been working overtime to study Omicron. Many questions remain unanswered, but here’s what they’ve learned so far.

Omicron moves fast. It spreads swiftly through populations, and infections develop quickly in individuals.

The time that elapses between when someone is first exposed to the virus and when they develop symptoms is known as the incubation period.

average incubation period

average

incubation period

Research suggests that the original version of the coronavirus and early variants had an incubation period of about five days, on average. The Delta variant seems to move faster, with an average incubation period of about four days. Omicron is swifter still, with an incubation period of roughly three days, according to a recent C.D.C. study.

The amount of virus that builds up in someone’s body is known as viral load. In general, people are thought to be most infectious when their viral loads are high.

In a recent study of the Alpha and Delta variants, researchers found that people tended to reach their peak viral loads about three days after infection and clear the virus about six days after that, on average.

Whether Omicron follows the same pattern remains to be seen. In one preliminary study, researchers found that Omicron infections were about a day shorter than Delta infections and resulted in slightly lower peak viral loads, on average. But the difference might be due to higher rates of pre-existing immunity — as a result of vaccination or prior infection — among the people who were infected with Omicron. Another research team found that among vaccinated people with breakthrough infections, Omicron and Delta produced similar levels of infectious virus.

Other data suggest that Omicron may not act like previous variants. Animal and laboratory studies indicate that it may not be as good at infecting the lungs as Delta, but that it may replicate more quickly in the upper respiratory tract.

The variant may have other unique characteristics, too. One small study found that antibodies produced after an Omicron infection seem to protect against Delta, but Delta infections offer little protection against Omicron. If the finding holds up, it means that Delta may soon have trouble finding hospitable hosts — and that Omicron is likely to replace Delta rather than co-exist with it.

Omicron appears to cause less severe disease than Delta. In one recent study, researchers found that people with Omicron infections were less likely to be hospitalized, end up in the I.C.U. or require mechanical ventilation than those with Delta infections.

One possible explanation is that Omicron is less likely to damage the lungs than previous variants. A variant that proliferates primarily in the upper respiratory tract may cause less severe disease in most people. One indication of reduced severity is that unvaccinated people seem less likely to be hospitalized with Omicron than with Delta.

But Omicron’s apparent mildness may also stem from the fact that it is infecting far more vaccinated people than Delta did. Omicron is skilled at evading the antibodies produced after vaccination, which is leading to more breakthrough infections, but vaccinated people are still protected from the most severe disease. Booster shots of mRNA vaccines are 90 percent effective against hospitalization with Omicron, according to the C.D.C.

Still, doctors cautioned, although the variant may be milder on average, some patients, especially those who are unvaccinated or have compromised immune systems, may become severely ill from Omicron infections. And it’s too early to know whether breakthrough cases of Omicron might result in long Covid.

Because Omicron replicates so fast and the incubation period is so short, there is a narrower window in which to catch infections before people begin to transmit the virus.

Earlier in the pandemic, people were advised to use a rapid test five to seven days after a potential exposure to the virus. Given Omicron’s shorter incubation period, many experts now recommend taking a rapid test two to four days after a potential exposure. (They also recommend taking at least two rapid tests, about a day apart, in order to increase the odds of detecting an infection.)

People who are testing to reduce the risk of transmitting the virus to others, for example at an upcoming gathering, should test as close as possible to the event itself, experts said.

There is still debate over whether rapid antigen tests might be less sensitive to Omicron than other variants. P.C.R. tests are more sensitive than rapid tests, which means they are likely to detect the virus earlier in the course of infection, but they take longer to return results.

The C.D.C. recently loosened its isolation guidelines for people who are infected with the virus. Previously, the agency recommended that people who test positive for the virus remain isolated for 10 days.

The new guidelines say that infected people can leave isolation after five days if they are asymptomatic or their symptoms are resolving and they are fever-free. People should wear well-fitting masks for an additional five days when around other people.

avoid travel,

wear a mask

The agency said these changes were prompted by data suggesting that transmission of the virus is most likely in the day or two before symptoms appear and the two or three days after.

But scientists have noted that some people may be infectious for longer than that, and some criticized the agency for not recommending that people receive a negative result on a rapid test before ending their isolation periods.

The agency subsequently updated its guidelines to note that people who wanted to test should take a rapid antigen test “towards the end” of the five-day isolation period but stopped short of formally recommending it.

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Quiz: Is Pluto a Planet? What Makes a Planet a Planet, Anyway? - The New York Times

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This debate about the icy world that used to be the ninth planet of the solar system is as much linguistics as science, and it is not a question with simple answers.

But it is a fascinating story about an ancient word with shifting meanings, humanity’s evolving views of its place in the cosmos and the process of scientific discovery, which like all human endeavors, can be messy and contentious.

Are you open to changing your mind about Pluto? Let’s ask a few questions to see where you stand on this question of planetary importance.

Do you think Pluto should be considered a planet?

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Play mini golf on a course made of unusual congressional districts

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How COVID cases and symptoms compare to 2021 surge as omicron rages

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Here are some shocking stats and numbers about the COVID-19 pandemic in 2021

From vaccinations to variants, here are some of the most shocking pandemic stats from 2021.

Staff video, USA TODAY

Amid another holiday season in the COVID-19 pandemic, Americans are once again trying to figure out how to safely gather and travel.

The latest threat is the omicron variant, which accounts for more than 73% of new COVID-19 infections in the nation and has been canceling major events as well as forcing schools to go virtual. 

Most of the U.S. is in the red, showing high rates of transmission. Northern states such as New York, Illinois, Wisconsin as well as Florida, Georgia, Alabama are among areas hardest hit. Areas reporting lower transmission include underpopulated areas such as Wheeler County, Oregon, Trinity, Country, California and Wayne County, Mississippi. 

Vaccination efforts also vary by area. Vermont, Puerto Rico, Rhode Island, Maine and Connecticut continue to report the highest COVID-19 vaccination rates while Idaho, Alabama and Wyoming report the lowest.

Need a COVID booster?: A guide to mixing and matching Pfizer, Moderna, J&J booster shots

New COVID treatments are coming: Will they help combat the omicron onslaught

The U.S. has recorded more than 52.7 million confirmed COVID-19 cases and more than 818,000 deaths, according to Johns Hopkins University data. Global totals total more than 281.5 million cases and 5.4 million deaths. More than 205 million Americans – 61.8% –  are fully vaccinated, according to the CDC.

As the omicron coronavirus variant accounts for the majority of new cases, the CDC is altering their medications and defense against the virus. The Food and Drug Administration authorized on Dec. 22 the use of Pfizer's Paxlovid, a series of pills, taken at home that prevent nearly 90% of severe COVID-19 among those at high risk.

And on Dec. 23, the FDA authorized use of a second antiviral, molnupiravir, which appears to prevent progression to severe disease about 30% of the time.

"As we face omicron, the nation's medicine cabinet of treatments gives us more options to protect the American people," said Jeff Zients, the White House Coronavirus Response Coordinator. "We have tools to keep people safe and we will continue to use them.

The demand of molnupiravir is coming from all states, including Texas where supplies are already low. The Texas Department of State Health Services announced on Dec. 27 that its regional infusion centers in Austin, El Paso, Fort Worth, San Antonio and The Woodlands have run out of the monoclonal antibody sotrovimab.

CDC continues to recommend wearing a mask in public indoor settings in areas of high community transmission, regardless of vaccination status.

Here's how the ratings break down overall by county:

The Centers for Disease Control and Prevention on Dec. 27 decreased the time it recommends people should isolate after testing positive for COVID-19 and quarantine after coming into contact with someone who tests positive. 

The new recommendations are for:

Isolation: For those who are infected with COVID-19, isolation starts the day a person tests positive. The CDC now recommends isolating for five days and going back to normal activities if a person is not showing any symptoms after that period. Originally, the isolation period was 10 days. 

Quarantine: For those who come in close contact with someone who tests positive for COVID-19.  The CDC is now recommending those who are vaccinated and received a booster shot can skip quarantining if they wear a face mask for at least 10 days. If a person is vaccinated and has not gotten a booster, or if they are partly vaccinated or not vaccinated at all, the CDC recommends a five-day quarantine, then wearing a mask in public for an additional five days.

Learn more: Changes to CDC quarantine guidelines

SOURCE USA TODAY Network reporting and research; Centers for Disease Control and Prevention; Kaiser Health News; Associated Press; <a href="http://nature.com" rel="nofollow">nature.com</a>

Contributed: Karen Weintraub, Janie Haseman, Mitchel Thorson, Javier Zarracina and Ramon Padilla USA TODAY,

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Novak Djokovic and Fellow Star Vaccine Skeptics Are Increasingly Scorned https://www.nytimes.com/2022/01/06/sports/djokovic-rodgers-irving-coronavirus.html

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2021 Map technology in review

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December 23, 2021

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