COVID-19’s omicron variant: What we know now

The omicron variant of the SARS-CoV-2 virus that causes COVID-19 was first identified in South Africa in late November and has since become the dominant coronavirus strain there.

Omicron has also been named a “variant of concern” by the World Health Organization and has been identified in COVID-19 cases around the world, including many cities around the United States. But as with every new COVID-19 variant that’s cropped up, scientists are racing to understand it.

We asked infectious diseases specialist and head of Internal Medicine David Tweardy, M.D., to share details about this latest mutation.

What do we know about the omicron variant?

The truth is, not very much. Early indicators can give us some idea of where things might go, but it’s really too soon in this saga to tell. We won’t actually know until we have more data.

The three biggest questions on everyone’s mind right now are:

• Is this strain more transmissible?
• Does it cause more severe infection?
• Will immunity derived from a previous infection or a vaccine protect me from it?

Whether we get a true surge from omicron hangs on the answer to that first question, in particular.

So, is omicron more transmissible than other COVID-19 variants?

Early indicators suggest that omicron may be more transmissible. But that is still conjecture at this point, so I wouldn’t take it to the bank. The mu variant kind of took over Columbia, too, but then it petered out. And the delta variant is still causing more than 99% of all infections in this country and around the world, except for South Africa. So, we’ll have to see what omicron does here and in other countries first.

Does omicron cause more severe infections?

Early data suggests that omicron may actually cause milder disease, as there has not been as much of a corresponding jump in hospital admissions as there was with spikes in infections caused by earlier variants.

Many of the South African patients testing positive for it did not even come into the hospital for COVID-19. They came in for other reasons, then got tested and were found to be positive. So far, the main symptoms being reported have also been milder: severe fatigue, body aches, and headaches.

Do the COVID-19 vaccines and/or antibodies from previous infection protect against omicron?

No vaccine or previous infection is going to be entirely protective against any new variant. But will those provide some protection against omicron? I’d say yes. It may not be as good as it was against delta or alpha, but that’s not really surprising. Viruses change over time, and about 30 mutations have already been identified in omicron’s spike proteins, which are the portion of the virus that actually attaches to cells.

If you still haven’t gotten vaccinated, though — or you haven’t gotten your COVID-19 booster and are eligible to do so — it’s important to go ahead and get vaccinated. We’re going to continue facing new variants, and even if protection declines a little against new variants, the protection provided by vaccines is still better than nothing at all. And these vaccines continue to work well against the delta variant, which is still the dominant strain in the United States.

One study reported that omicron is three times more likely to cause reinfection than delta. What does that mean?

It means that if you had a previous infection caused by the delta variant and you recovered from it, you are three times more likely to develop another case of COVID-19 if you’re exposed to omicron than you are if you’re re-exposed to delta.

Previous infection confers some immunity, but it’s looking like omicron is able to overcome resistance derived from both that and vaccination. The protection appears to be not as effective against omicron as it was against delta.

Not enough data is available yet to make a firm assertion about fully vaccinated people. But being vaccinated is still going to make you up to five times less likely to be infected with any strain of the virus than you would be if you remained unvaccinated. So, it’s still very worthwhile to get vaccinated.

What do you make of the reports that say omicron may have spread through hallway air among quarantined people in a Hong Kong hotel?

Those types of exposures actually wouldn’t surprise me. If an infected individual expelled some virus from their mouth, aerosol particles could have gotten through the duct work and even infected someone in another room.

But that’s been true of previous strains, too, so I don’t think that necessarily makes omicron more transmissible. It also depends on how carefully any other possibilities were ruled out.

How can people protect themselves against omicron?

Get vaccinated immediately, if you haven’t been already. And don’t delay your booster shots. Get them as soon as you’re eligible. The best protection you can get is still to have the highest level of immunity possible, and that only comes with full vaccination.

It’s also very important to continue masking up indoors if you’re in an area of high transmission and/or you don’t know the vaccination status of those around you. This is especially important as we enter the holiday season.

You should also continue to guard against the coronavirus and other viruses and infections, by:

• Maintaining physical distancing
• Getting vaccinated against the flu
• Practing good hand hygiene
  

Any special guidance for cancer patients or immunocompromised people?

No. Just make sure you consult your care team about the best time to get vaccinated. And get your third dose as soon as possible, if you haven’t already done so.

Also, stay alert for any new guidance related to the need for additional boosters. Pfizer has indicated that a fourth dose might be necessary to confer maximum protection, and many vaccine companies are already working to develop vaccines that also target omicron.

Anything else you want people to know about the omicron variant?

I am very excited about the two new antiviral medications being developed right now. Both of them should be effective against omicron, and both are close to receiving emergency use authorization from the Food and Drug Administration (FDA).

Schedule a COVID-19 vaccine appointment at MD Anderson. Appointments are open to patients, caregivers and the general public.

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