First Choice Neurology

What You Need to Know About the Rapidly Spreading Omicron Variant

Omicron (B.1.1.529) is now in most states and is rapidly increasing the number of COVID-19 cases. The CDC expects that anyone with Omicron infection can spread the virus to others, even if they are vaccinated or don’t have symptoms.

According to the CDC, about 73% of the new COVID cases in the U.S. are caused by the rapidly spreading Omicron variant, up from about 12% the week before. Omicron has some deletions and more than 30 mutations, several of which overlap with those in the Alpha, Beta, Gamma, and Delta. They are known to lead to increased transmissibility, higher viral binding affinity, and higher antibody escape.

There is not enough data to know if Omicron infections, reinfections, and breakthrough cases, cause more severe illness or death than infection with other variants. One study recently conducted in the UK finds no evidence of Omicron having lower severity than Delta. Researchers estimate the risk of reinfection by Omicron is 5.4 times greater than for the Delta.

CDC data showed the most common symptoms so far are cough, fatigue, congestion, and a runny nose. Overall, the symptoms for COVID reported by the CDC include:

  • Fever or chills
  • Cough
  • Shortness of breath or difficulty breathing
  • Fatigue
  • Muscle or body aches
  • Headache
  • New loss of taste or smell
  • Sore throat
  • Congestion or runny nose
  • Nausea or vomiting
  • Diarrhea

Experts are now advising you to upgrade your mask when you’re in public indoor spaces. Preliminary data from scientists at the University of Hong Kong has shown that Omicron multiplies 70 times faster inside human respiratory tract tissue than the Delta variant does. That study also found that omicron reaches higher levels in respiratory tract tissue 48 hours after infection, compared with delta.


Protect Yourself and Others

Protect yourself and others by getting your COVID-19 vaccines and booster, wear a high-filtration mask indoors in an area of high transmission, even if you are fully vaccinated. Remember to social distance, and get tested to prevent the spread of COVID-19.


Rapidly Spreading Omicron VariantVaccines & Boosters

Vaccines protect people from COVID-19, slow transmission, and reduce the likelihood of new variants emerging. They are highly effective at preventing severe illness, hospitalizations, and death. However, breakthrough infections in people who are fully vaccinated are likely to occur.

The CDC recommends that everyone 5 years and older gets fully vaccinated. Everyone 18 years and older should get a booster shot at least two months after their initial J&J/Janssen vaccine or six months after the Pfizer-BioNTech or Moderna series. The CDC has updated its recommendations for COVID-19 vaccines with a preference for people to receive an mRNA COVID-19 vaccine (Pfizer-BioNTech and Moderna).


High-Filtration Masks

The CDC continues to recommend wearing a mask in public indoor settings especially with the omicron variant, regardless of vaccination status. Experts are now advising to wear N95 or high-filtration respirators in public indoor spaces for the best protection.

“Cloth masks are not going to cut it with omicron,” says Linsey Marr, a researcher at Virginia Tech who studies how viruses transmit in the air.

N95, KN95, and KF94 respirators are all made out of material with an electrostatic charge, which pulls particles in as they’re floating around and prevents you from inhaling them. If you can’t get a high-filtration mask, consider topping a surgical mask with a cloth mask to ensure a tighter fit. It won’t offer as much protection as an N95, but it will be a big improvement over a cloth mask alone.


Ventilation and Filtration

Good ventilation, along with other preventive actions, like staying 6 feet apart and wearing masks, can help prevent you from getting and spreading COVID-19. Bringing fresh, outdoor air into your home helps keep virus particles from accumulating inside. Open doors and windows as much as you can. Use fans to move virus particles in the air from inside your home to outside.

In homes where the HVAC fan operation can be controlled by a thermostat, set the fan to the “on” position instead of “auto” when you have visitors. This allows the fan to run continuously, even if heating or air conditioning is not on.  If you don’t have an HVAC system or just want extra filtration, consider using a portable high-efficiency particulate air (HEPA) cleaner. They are the most efficient filters on the market for trapping particles that people exhale when breathing, talking, singing, coughing, and sneezing.  Turn on the exhaust fan in your bathroom and kitchen. Use ceiling fans to help improve airflow in the home whether or not windows are open.

Avoid poorly ventilated spaces. Crowded places like restaurants, bars, fitness centers, or movie theaters put you at higher risk for COVID-19. Avoid indoor spaces that do not offer fresh air from the outdoors as much as possible. If indoors, bring in fresh air by opening windows and doors, if possible.

Virus particles from an infectious person can linger in the air indoors for minutes or even hours after they leave a room in some situations, says Dr. Abraar Karan, an infectious disease physician at Stanford University.



At Home Antigen Test imageUpdated 12/27/21 – Regardless of the test type, a positive test result means that you have an infection and should isolate for 5 days, if asymptomatic, followed by 5 days of wearing a mask when around others. For people who are unvaccinated or are more than six months out from their second mRNA dose (or more than 2 months after the J&J vaccine) and not yet boosted, CDC now recommends quarantine for 5 days followed by strict mask use for an additional 5 days. Alternatively, if a 5-day quarantine is not feasible, it is imperative that an exposed person wear a well-fitting mask at all times when around others for 10 days after exposure. Individuals who have received their booster shot do not need to quarantine the following exposure but should wear a mask for 10 days after the exposure.  For all those exposed, best practice would also include a test for SARS-CoV-2 at day 5 after exposure. If symptoms occur, individuals should immediately quarantine until a negative test confirms symptoms are not attributable to COVID-19.

Tests for SARS-CoV-2 tell you if you have an infection at the time of the test. This type of test is called a “viral” test because it looks for viral infection. Antigen or Nucleic Acid Amplification Tests (NAATs) are viral tests.

Rapid tests for COVID-19 are simple to administer and ready within minutes, but if you don’t use rapid tests in the right way at the right time, they won’t provide accurate results. Rapid tests are designed to yield positive results when your viral load is highest, and it takes at least a few days for it to get to that level. During that time, you may or may not develop prominent symptoms of Omicron, which can include cough, fatigue,  congestion, and a runny nose. But unlike delta, many patients are not losing their taste or smell. The symptoms could depend on vaccination status and underlying health conditions. In the unvaccinated, symptoms may be more severe.



Scientists are working to determine how well existing treatments for COVID-19 work. There are three monoclonal antibody treatments available in the U.S. to keep people infected from becoming seriously ill.

The one monoclonal antibody treatment that has performed well against Omicron in laboratory experiments is also the most recently authorized: sotrovimab, made by GlaxoSmithKline and Vir Biotechnology and cleared in May 2021. Already in high demand even before Omicron arose, the supply of sotrovimab is very limited for now.

Yesterday, the FDA gave emergency authorization for an antiviral produced by Pfizer called Paxlovid – the first monoclonal antibody pill. Paxlovid won’t be immediately available to help people infected with Omicron because current supplies are limited.

Today, the FDA granted emergency use authorization to Merck’s antiviral drug to treat adults with mild to moderate COVID-19 who are at risk for severe disease.

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