COVID-19 breakthrough infections and the omicron variant: What to know now

The number of breakthrough COVID-19 infections continues to climb, both in the United States and around the world. Many are now due to the omicron variant, as opposed to the delta variant, which still accounted for more than 90% of all documented COVID-19 infections in the U.S. as recently as mid-December.

So, what does this mean, from a practical standpoint? Is it okay to send your kids back to school after the holiday break? What should you do if you test positive for the virus now? Should you still get a vaccine booster shot, if you become infected with omicron before you can obtain one?

We checked in with Chief Infection Control Officer Roy Chemaly, M.D. for answers. Here’s what he had to say.

Are breakthrough infections more common with omicron than they were with previous strains?

Yes, I think so. We’re definitely seeing more breakthrough infections with omicron than delta, simply because the efficacy of the vaccines is lower against it.

Why is that? Does it mean the vaccines aren’t working?

No. Every variant is going to be at least slightly different from the ones that came before it. That’s just the nature of evolution. But omicron, in particular, has a lot of mutations that make it more transmissible and able to evade the passive immunity acquired from vaccination. So, the vaccines are not going to be as effective against it as they were against delta or other previous variants.

Is there still any value in getting vaccinated or getting a booster shot now?

Absolutely. Even with something like the flu, the goal is to reduce the overall number of infections, as well as the severity of the infections that still occur.

The existing, FDA-approved COVID-19 vaccines are still very effective at preventing serious illness. And that’s the most important thing. Because the milder your symptoms are, the less likely it is that you’re going to need hospitalization, or die from the underlying infection.

With a booster shot, your chances of getting COVID-19 are much lower than if you’re only fully vaccinated. That’s why it’s also very important for everyone who is eligible to get a booster.

Is omicron causing milder symptoms in people than previous variants did?

Anecdotally, I would say yes. In general, the symptoms people are presenting with appear to be less severe with omicron than with delta.

What are the primary symptoms of people infected with omicron? Do they differ from previous variants?

Most of the infections we’re seeing now are in people who are symptomatic rather than asymptomatic, meaning that infected people are showing symptoms more often than not. Their symptoms are generally flu-like and similar to those of previous variants. But in many cases, the headache, fever and coughing are milder.

The loss of taste and smell may also be much less prevalent with omicron than it was with delta. But again, this is all strictly anecdotal, not based on formal study.

What should someone do if they develop a breakthrough infection now?

If you’re asymptomatic, stay home for 5 days, then wear a mask for 5 days, per the Centers for Disease Control’s new quarantine guidelines.

If it’s a mild infection, quarantine yourself for 5 days. If your symptoms are resolving or you’re asymptomatic and/or back to your normal baseline after that, you can leave your house, but wear a mask for another 5 days. It is always recommended to wear a mask in the community and at any gathering.

If it’s a severe infection, monitor yourself carefully. And if you’re getting progressively worse instead of better, seek help. This is particularly true if you start experiencing shortness of breath, a severe cough, breathing problems, or other concerning symptoms of COVID-19.

If you’re an MD Anderson patient, I’d also suggest checking with your doctor for guidance that’s specific to you. We can use the FDA-approved anti-viral drug veklury (Remdesivir) or steroids in cancer patients who are sick enough to be hospitalized, whether it’s due to pneumonia, low oxygen levels, or some other issue.

But the two anti-viral drugs recently granted emergency use authorization by the Food and Drug Administration for use against COVID-19 are not available yet. And most available monoclonal antibodies don’t work against omicron, except for one kind called sotrovimab, which is very hard to get right now.

If someone develops a breakthrough infection after being fully vaccinated, but before receiving the booster shot, should they still try to get one?

Yes. My recommendation is to get a booster shot, even if you’ve already been infected. You’ll have to wait until you get better, of course, and be out of quarantine and not symptomatic. But I still recommend getting a booster as soon as you’re eligible, because natural immunity is not going to be as effective as what you’ll have if you get boosted.

Are there any special measures cancer patients or immunocompromised people should be taking to protect themselves right now?

Other than getting boosted or an additional dose, no. Talk to your doctor to be sure, of course, but generally speaking, cancer patients and other immunocompromised people should be taking the same public health measures right now that we’ve all been following to some degree for the past two years:

• masking all the time
• avoiding large gatherings
• practicing social distancing.

What guidance do you have for parents about sending their kids back to school after the holidays?

First, if your children are eligible, get them vaccinated. If they are 16 or older, get them boosted as soon as they are eligible. I would also have them keep wearing masks at school, especially during the first month of 2022, because we really don’t know how this pandemic is going to evolve. Will there be a sharp decline in cases or will this variant linger for months?

Based on what’s happening in South Africa, it may not linger very long. It may get better more quickly than it did with delta. But that’s impossible to predict, so I would still take all precautions until we know more.

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