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The omicron variant has now been detected in at least 39 states, and the new strain has caused COVID-19 cases to rise considerably throughout the US and the world. On Friday, the surge in COVID cases and outbreaks among players led the NFL to postpone multiple games for Week 15. 

On Thursday, New York state experienced its highest ever one-day number of positive cases. On Friday, the World Health Organization warned that COVID-19 cases double every 1.5 to 3 days in areas affected by the omicron variant.

Saturday morning, New York City Mayor Bill DeBlasio tweeted that the city posted a remarkable 5,263 new cases, and the mayor of London declared a "major incident" due to 26,418 new cases being reported in the past 24 hours.

In its press briefing Friday, the US Centers for Disease Control and Prevention again stressed the necessity of COVID-19 vaccine boosters. Dr. Anthony Fauci, chief medical adviser to President Joe Biden, presented several studies showing decreased effectiveness of primary COVID-19 vaccinations against Omicron, as well as evidence showing increased neutralization from booster shots. A third booster shot is urged by the CDC, and may eventually affect the definition of "fully vaccinated."

Scientists are still piecing together a picture of how easily the virus can pass from one person to another and evade protection provided by the primary vaccine doses of Pfizer, Moderna and J&J. Looking at the latest data, Fauci said on Wednesday that omicron can bypass much of the protection given by two shots of the mRNA Moderna and Pfizer vaccines: "The omicron variant undoubtably compromised the effects of a two-dose mRNA vaccine-induced antibodies and reduces the overall protection." More promising, Fauci said, is that boosters appear to restore the level of protection needed to guard against the omicron variant.

In the US, Biden is doubling down on urging vaccines and booster shots until more information on the new variant becomes available. As a result, the US administered 12.5 million shots in the first week of December, according to Jeff Zients, the White House coronavirus response coordinator. That's the highest number of weekly shots since May. Seven million of those were booster shots, Zients said.

So far, the COVID-19 vaccines have proven to be highly effective in preventing hospitalization and death, with people who are unvaccinated being over 10 times more likely to be hospitalized if infected. A CDC panel on Thursday recommended that those looking for a safe and effective vaccine should choose an mRNA option (Pfizer or Moderna) -- and not Johnson and Johnson's.

Here are 11 important things to know about omicron today. For more on COVID-19 boosters, here's a trick to easily get an appointment and a free ride. Here's how you'll soon get a COVID-19 test kit for free and details on mixing and matching vaccines.

Which NFL games have been postponed?

The NFL decided on Friday to postpone three games for Week 15. The game between the Las Vegas Raiders and Cleveland Browns, originally scheduled for Saturday, December 18, has been rescheduled for Monday, December 20.

Originally scheduled for Sunday, December 19, the Seattle Seahawks-Los Angeles Rams and Washington Football Team-Philadelphia Eagles games will now be played on Tuesday, December 21. The Browns, Rams, and Washington all have more than 20 players in COVID protocol because of positive tests.

On Friday, NFL commissioner Roger Goodell communicated with all 32 teams about the league's shift in policy. Goodell noted, "The emergence of the Omicron variant is precisely the kind of change that warrants a flexible response. Based on medical advice, we have instituted additional protocols as well as revised testing protocols for reinstating players and staff who have tested positive. We have also considered whether certain games should be rescheduled in light of current conditions."

A COVID vaccine booster is needed to guard against omicron

Early studies indicate a booster can guard against omicron. "Boosters ... enhance the vaccine protection against omicron," Fauci said on Wednesday. "Our booster vaccine regimens work against omicron."

"Individuals who have received two vaccines will most likely not have significant prevention from infection or any type of disease [from the new variant]," BioNTech CEO Uğur Şahin said last week. (Comirnaty, the brand name of the Pfizer vaccine, is manufactured by Pfizer and BioNTech.) Şahin said more information is needed to confirm the company's initial laboratory findings that indicate a third Pfizer vaccine dose is important to guard against the variant.

Why did the CDC panel recommend the Pfizer and Moderna vaccines over the one from Johnson & Johnson?

On Thursday, a CDC advisory panel voted to recommend that those looking for a safe vaccine pick either Moderna's or Pfizer's because of the risk of a potentially fatal blood clot issue associated with the Johnson & Johnson vaccine. Dr. Rochelle Walensky, director of the CDC, is expected to decide as soon as today whether to accept that panel's vote.

Is an omicron-specific vaccine needed?

Pfizer-BioNTech, Moderna and Johnson & Johnson have all said they are gearing up to create a vaccine specifically designed to combat omicron if it's needed.

Fauci on Wednesday said that there is no need for a variant-specific booster at this point. The current boosters appear to be effective against omicron.

So far, the omicron virus is producing mild symptoms

According to Fauci, preliminary information seems to indicate omicron may produce less serious symptoms than initially feared: "We're getting anecdotal information ... that the level of severity appears to be maybe a bit less than in the delta," he said Sunday.

Some hopeful news on omicron came recently from South Africa. At a press briefing Thursday, Minister of Health Dr. Joe Phaahla noted that hospitalizations are "definitely much lower" than during the country's third wave, in June 2021. Only 1.7% of COVID-19 cases in this fourth wave's second week of infections involved hospitalization, compared with 19% during the second week of the third wave.

The new COVID variant may spread more easily than delta

It could still be two or three weeks till we know more about how easily omicron can be passed between people and how resistant the mutated virus is against the current crop of vaccines, but Fauci on Tuesday at a White House briefing said that early data also suggests omicron could be more infectious than the delta variant and is replacing delta as the dominant COVID-19 strain in South Africa.

Omicron confirmed in 39 US states

It makes up 3% of the cases in the US. In New York and New Jersey, however, it could make up 13% of new infections.

The variant has been detected in 39 states across the country, from Washington to Mississippi and Texas to Utah. The US and other countries were already bracing for an increased caseload as colder weather and holiday gatherings brought more people indoors together. Now, projections of a winter surge of the dominant delta variant join concerns about omicron's spread.

Add an increasing number of flu infections, and experts worry about a "twindemic" of the two illnesses.

Omicron could become the dominant COVID variant in Europe within months

In Europe, omicron could become the most common COVID-19 variant in months, according to the European Centre for Disease Prevention and Control.

"Mathematical modeling indicates that the Omicron VOC is expected to cause over half of all SARS-CoV-2 infections in the EU/EEA within the next few months" due to early understandings of the omicron variant's high transmissibility between people, the body said in a Dec. 2 briefing (PDF). 

Scientists studying the omicron variant in South Africa, where it was first reported to the World Health Organization, have said it's spreading more than twice as fast as the delta variant, according to reporting from the New York Times. But what isn't yet known is whether the spread is hastened because the mutations make it easier to spread among people, if vaccines are less effective against this strain or for some other reason. The study cited by NYT has not yet been published or peer-reviewed.

Omicron has similarities to the delta variant's mutation

COVID latches onto cells using a spike protein in its structure. Omicron has more mutations than the delta variant, which is considered at least twice as contagious as previous strains. While it isn't clear yet whether omicron is more or less contagious than delta, the presence of those mutations is one cause of concern. 

That may be one reason numerous have banned travel from some countries in southern Africa and increased travel restrictions to include a negative COVID-19 test 24 hours before travel, regardless of vaccination status.

COVID PCR tests can identify the omicron variant

Most PCR tests to identify the presence of COVID-19 in the body are free (COVID-19 tests for international travel are the main exception). So it's good news that the existing nasal swab test has been found to detect the omicron variant; a blood test or other procedure is so far unnecessary.

"Fortunately for us, the PCRs that we mostly use would pick up this very unusual variant that has a real large constellation of mutations," Fauci said in a Nov. 29 press briefing.

Booster shots and vaccines are urged to help prevent omicron's spread

On Dec. 2, Biden announced a plan to help protect the US against the omicron variant this winter. It includes:

• Outreach programs to contact people eligible to receive booster shots.
  
• Making at-home COVID-19 tests "free" for everyone.
• Tighter travel restrictions that require a negative COVID-19 test 24 hours before departure.
• Paid time off for federal workers to get booster shots.
• Securing antiviral pills as a treatment for people who become infected with COVID-19 (these are recommended but not yet FDA-approved).
• Sending 200 million more doses of COVID-19 vaccine to international countries in the next 100 days (280 million have already been sent).

For additional COVID-19 guidance, here's what to know about new travel restrictions, how to store your vaccine card on your phone and what to do if you lose your vaccine card.

The information contained in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified health provider regarding any questions you may have about a medical condition or health objectives.